title: Shyam Singha Roy

text: In West Bengal in 1969, Shyam Singha Roy is an influential social reformer and revolutionary writer with communist ideologies, who comes from a conservative family. As his family disapproves of his methods, he decides to leave but stumbles upon Maitreyi, a devadasi from Bangladesh who dances in the temple during the Navaratri. Despite being an atheist, Shyam visits the temple every night to see Maitreyi. One night, he asks her to sneak out of the temple with him and she reluctantly agrees. Shyam and Maitreyi fall for each other, and Shyam renames Maitreyi as Rosie. They decide to elope, however, on that night, the temple's high priest Mahant, who sexually preys on devadasis, selects a young girl to sleep with, to which Rosie opposes. Mahant abuses Rosie in anger and disrespects her by urinating on her. Upon discovering this, an enraged Shyam attacks Mahant in the temple. He punishes him by severing off his penis and throwing him onto burning coal, killing him and removing the necklace on Rosie, implying discontinuing her duties as Devadasi.


title: Shyam Singha Roy

text: Shyam and Rosie move to Calcutta where he starts working in a printing press. By 1977, Shyam becomes an accomplished yet controversial writer of his time. On Rosie's suggestion, Shyam opens up a trust to rehabilitate devadasis. Shyam's brother, Manoj, requests him to visit their village to see their ailing elder brother. However, upon their arrival, his two elder brothers send Manoj to bring tender coconuts, which turns out to be a ploy to murder Shyam for bringing disrepute to their family by killing Mahant at the temple and marrying Rosie, who is not of their caste. Manoj arrives but is unable to save Shyam, who dies in front of him. The two elder brothers are killed in an accident a few years later and Shyam's nephews now run SR Publications, Singha Roy's publishing house.


title: Shyam Singha Roy

text: In the present, Vasu visits the printing press in Kolkata where Shyam worked. However, he is told that Shyam and Rosie died decades ago, Rosie having left to find Shyam. Padmavathi submits Vasu's hypnosis report as evidence in the court that Shyam Singha Roy is reincarnated as Vasu. However, the prosecution lawyer objects, stating there is no scientific evidence of reincarnation. While the court is about to give its judgment, an 85-year-old Manoj visits the court and declares Vasu to be Shyam's reincarnation. Upon being asked for proof, Manoj explains that Vasu adapted Shyam's short story "Varna" as his short film Varnam, but that story was never published in the public domain. Manoj submits Shyam's hand-written manuscript of the story as proof and withdraws the case as the chairman of SR Publications. Vasu is acquitted of all charges.


title: Shyam Singha Roy

text: Manoj reveals to Vasu that Rosie is alive and waiting for him. Vasu then visits an aged Rosie, who now runs a dance school named after Shyam. Upon meeting Vasu, both have an emotional reunion and as per her wish, Rosie dies peacefully in his arms.


title: Shyam Singha Roy

text: On 18 December 2019, Rahul Sankrityan narrated a script to Nani, which was considered to be an "innovative story". The project was initially reported to be produced under Suryadevara Naga Vamsi's Sithara Entertainments banner, who initially worked with Nani in "Jersey" (2019). The film was announced in February 2020, with the title "Shyam Singha Roy", and was expected to go on floors in May 2020, although the launch was delayed due to the COVID-19 pandemic in India. During March 2020, A. R. Rahman was approached to compose music for the film, and Nirav Shah was in charge of handling the cinematography. Later Anirudh Ravichander was announced as the composer as Rahman apparently did not accept the offer. The film was meant to be Anirudh's third collaboration with Nani after "Jersey" and "Nani's Gang Leader".


title: Shyam Singha Roy

text: The film was expected to be made on a huge scale, marking the most expensive film in Nani's career. However, producer Naga Vamsi wanted to cut down the budget citing the pandemic, as the estimated cost was much higher; Vamsi wanted to shelve the project, while Nani was completing the shoot of "Tuck Jagadish". Due to differences of opinion between Nani and Vamsi, the production was handed over to Venkat Boyanapalli, who would be producing the film under his newly established banner Niharika Entertainment.


title: Shyam Singha Roy

text: On 25 October 2020, a new poster was launched coinciding with Dusshera, with the inclusion of composer Mickey J. Meyer, cinematographer Sanu John Varghese and editor Naveen Nooli. Director Sankrityan revealed that the film is based on the theme of reincarnation and partially set against the backdrop of Kolkata.


title: Shyam Singha Roy

text: Sai Pallavi, who also collaborated with Nani in "Middle Class Abbayi", was cast in the film. It was reported that Rashmika Mandanna was approached for a lead role, although Krithi Shetty was finalized later. Madonna Sebastian was also confirmed as a lead, marking her come back to the Telugu cinema after "Premam" (2016). Murali Sharma, Abhinav Gomatam, and Rahul Ravindran were later included in the cast. In March 2021, Bengali actor Jisshu Sengupta was signed to play an important role in the film. This also marked the Telugu debut for Bharatanatyam dancer, Leela Samson.


title: Shyam Singha Roy

text: The film was launched at a private ceremony in Hyderabad on 11 December 2020, in the presence of the cast and crew, and Nani's father gave the muhurat shot for the film. Principal photography began on 21 December 2020 in Hyderabad, India. A Kolkata-themed street along with the Kalighat Kali Temple was constructed on a budget of 6 crores. In February 2021, the team began filming crucial scenes in Kolkata. Filming was briefly halted due to COVID-19 lockdown in India and was resumed in July 2021. The Kolkata set in Hyderabad was damaged due to heavy rains and was restored by art director Avinash Kolla. Filming was completed on 26 July 2021 and post-production began.


title: Shyam Singha Roy

text: The soundtrack album is composed by Mickey J. Meyer and the audio rights were acquired by Saregama. The song "Pranavalaya" is based on the Carnatic Raga "Udayaravichandrika" or "Shuddha Dhanyasi" (known as Raag "Dhani" in Hindustani Music).


title: Shyam Singha Roy

text: The film was originally scheduled for release on 24 December 2020, coinciding with Christmas, but was eventually postponed as filming was delayed due to the COVID-19 pandemic. The film was released on 24 December 2021. Apart from Telugu, the film was dubbed and released in Tamil, Malayalam, and Kannada languages.


title: Shyam Singha Roy

text: Gemini TV acquired the satellite rights of the film in Telugu, while Netflix acquired the digital rights in Telugu, Tamil, and Malayalam. The film began streaming through Netflix on 21 January 2022.


title: Shyam Singha Roy

text: "Shyam Singha Roy" received mixed to positive reviews with critics praising the performances while criticizing the screenplay. Sangeetha Devi Dundoo of "The Hindu" opnied that "This isn’t to say that this is a sub par film. But with a little more thought, it could have been way smarter. Despite these niggles, there’s plenty going for "Shyam Singha Roy"". Giving a rating of 3.5 out of 5, Neeshita Nyayapati of "The Times of India" wrote: ""Shyam Singha Roy" might not have a story that’s completely out of the box but the staging does have the potential to bowl you over. Barring the underwhelming aspects, give this one a chance this weekend if you’re longing for something that’s well-made and backed by a stellar cast", appreciating the acting performances of Nani and Sai Pallavi, and the story. Calling it "engrossing", "The News Minute"'s Sowmya Rajendran too gave a rating of 3.5 out of 5. She has praised the screenplay, story, direction and acting by the ensemble cast, commenting that "Sai Pallavi is the show-stealer, performing a role that's tailor-made for her".


title: Shyam Singha Roy

text: Manoj Kumar R of "The Indian Express" called the film "a revolutionary romantic tale". He finally wrote: "To director-writer Rahul Sankrityan’s credit, the film’s hero lives and fights by the pen, instead of resorting to violence. The period portions of the film is a sight for sore eyes. The retro look of Nani and Sai Pallavi oozes charm. Pallavi’s classical dance performance draped in a red saree is a sight to behold. Just her presence on the screen elevates a scene to another level". "Firstpost"'s Sankeertana Varma praised the technical department of the film stating: "Navin Nooli's editing, too, helps intertwine the two timelines to give the viewer a glimpse into Vasu's psyche—what he is seeing and how unclear it all is. Sanu John Varughese's cinematography and Kolla Avinash's production design shoulder the film as well. While Sanu's camera daftly manoeuvres between the two timelines—the way Sai Pallavi's introduction song is shot, choreographed, and cut needs special mention, Avinash's period detailing does transport the viewer to a time gone by". Writing for "India Today", Janani K said that "Cinematographer Sanu John Varghese’s visuals, especially in the period portions, are exceptional. Music by Mickey J Meyer tugs at our heartstrings. Shyam Singha Roy could have been a taut and crisp story about reincarnation. Since it takes a familiar route, the overall effect takes a dip". Prakash Pecheti of "Telangana Today" felt that the film falls short of becoming a masterpiece. He further wrote: "‘Shyam Singha Roy’ would’ve been an engaging one if characters had some depth in establishing them. One might even think that a realistic approach might have fetched the story well".


title: Shyam Singha Roy

text: Movie overall Business valued at 22 crores and it collected 9.60Cr in Nizam,10 crore in Andhra Pradesh and in both telugu states it collected 20 crores distributor share of gross 33.50 crores. Total Worldwide it collected share of 26.5 crores and declared as Super Hit.


title: Gallbladder

text: In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath the liver, although the structure and position of the gallbladder can vary significantly among animal species. It receives and stores bile, produced by the liver, via the common hepatic duct, and releases it via the common bile duct into the duodenum, where the bile helps in the digestion of fats.


title: Gallbladder

text: The gallbladder can be affected by gallstones, formed by material that cannot be dissolved – usually cholesterol or bilirubin, a product of haemoglobin breakdown. These may cause significant pain, particularly in the upper-right corner of the abdomen, and are often treated with removal of the gallbladder (called a cholecystectomy). Cholecystitis, inflammation of the gallbladder, has a wide range of causes, including result from the impaction of gallstones, infection, and autoimmune disease.


title: Gallbladder

text: The gallbladder is a hollow organ that sits in a shallow depression below the right lobe of the liver, which is grey-blue in life. In adults, the gallbladder measures approximately in length and in diameter when fully distended. The gallbladder has a capacity of about .


title: Gallbladder

text: The gallbladder is shaped like a pear, with its tip opening into the cystic duct. The gallbladder is divided into three sections: the "fundus", "body", and "neck". The "fundus" is the rounded base, angled so that it faces the abdominal wall. The "body" lies in a depression in the surface of the lower liver. The "neck" tapers and is continuous with the cystic duct, part of the biliary tree. The gallbladder fossa, against which the fundus and body of the gallbladder lie, is found beneath the junction of hepatic segments IVB and V. The cystic duct unites with the common hepatic duct to become the common bile duct. At the junction of the neck of the gallbladder and the cystic duct, there is an out-pouching of the gallbladder wall forming a mucosal fold known as "Hartmann's pouch".


title: Gallbladder

text: Lymphatic drainage of the gallbladder follows the cystic node, which is located between the cystic duct and the common hepatic duct. Lymphatics from the lower part of the organ drain into lower hepatic lymph nodes. All the lymph finally drains into celiac lymph nodes.


title: Gallbladder

text: The gallbladder wall is composed of a number of layers. The innermost surface of the gallbladder wall is lined by a single layer of columnar cells with a brush border of microvilli, very similar to intestinal absorptive cells. Underneath the epithelium is an underlying lamina propria, a muscular layer, an outer perimuscular layer and serosa. Unlike elsewhere in the intestinal tract, the gallbladder does not have a muscularis mucosae, and the muscular fibres are not arranged in distinct layers.


title: Gallbladder

text: The mucosa, the inner portion of the gallbladder wall, consists of a lining of a single layer of columnar cells, with cells possessing small hair-like attachments called microvilli. This sits on a thin layer of connective tissue, the lamina propria. The mucosa is curved and collected into tiny outpouchings called "rugae".


title: Gallbladder

text: A muscular layer sits beneath the mucosa. This is formed by smooth muscle, with fibres that lie in longitudinal, oblique and transverse directions, and are not arranged in separate layers. The muscle fibres here contract to expel bile from the gallbladder. A distinctive feature of the gallbladder is the presence of "Rokitansky–Aschoff sinuses", deep outpouchings of the mucosa that can extend through the muscular layer, and which indicate adenomyomatosis. The muscular layer is surrounded by a layer of connective and fat tissue.


title: Gallbladder

text: The outer layer of the fundus of gallbladder, and the surfaces not in contact with the liver, are covered by a thick serosa, which is exposed to the peritoneum. The serosa contains blood vessels and lymphatics. The surfaces in contact with the liver are covered in connective tissue.


title: Gallbladder

text: The gallbladder varies in size, shape, and position between different people. Rarely, two or even three gallbladders may coexist, either as separate bladders draining into the cystic duct, or sharing a common branch that drains into the cystic duct. Additionally, the gallbladder may fail to form at all. Gallbladders with two lobes separated by a septum may also exist. These abnormalities are not likely to affect function and are generally asymptomatic.


title: Gallbladder

text: The location of the gallbladder in relation to the liver may also vary, with documented variants including gallbladders found within, above, on the left side of, behind, and detached or suspended from the liver. Such variants are very rare: from 1886 to 1998, only 110 cases of left-lying liver, or less than one per year, were reported in scientific literature.


title: Gallbladder

text: An anatomical variation can occur, known as a Phrygian cap, which is an innocuous fold in the fundus, named after its resemblance to the Phrygian cap.


title: Gallbladder

text: The gallbladder develops from an endodermal outpouching of the embryonic gut tube. Early in development, the human embryo has three germ layers and abuts an embryonic yolk sac. During the second week of embryogenesis, as the embryo grows, it begins to surround and envelop portions of this sac. The enveloped portions form the basis for the adult gastrointestinal tract. Sections of this foregut begin to differentiate into the organs of the gastrointestinal tract, such as the esophagus, stomach, and intestines.


title: Gallbladder

text: During the fourth week of embryological development, the stomach rotates. The stomach, originally lying in the midline of the embryo, rotates so that its body is on the left. This rotation also affects the part of the gastrointestinal tube immediately below the stomach, which will go on to become the duodenum. By the end of the fourth week, the developing duodenum begins to spout a small outpouching on its right side, the hepatic diverticulum, which will go on to become the biliary tree. Just below this is a second outpouching, known as the "cystic diverticulum", that will eventually develop into the gallbladder.


title: Gallbladder

text: The main functions of the gallbladder are to store and concentrate bile, also called gall, needed for the digestion of fats in food. Produced by the liver, bile flows through small vessels into the larger hepatic ducts and ultimately through the cystic duct (parts of the biliary tree) into the gallbladder, where it is stored. At any one time, of bile is stored within the gallbladder.


title: Gallbladder

text: When food containing fat enters the digestive tract, it stimulates the secretion of cholecystokinin (CCK) from I cells of the duodenum and jejunum. In response to cholecystokinin, the gallbladder rhythmically contracts and releases its contents into the common bile duct, eventually draining into the duodenum. The bile emulsifies fats in partly digested food, thereby assisting their absorption. Bile consists primarily of water and bile salts, and also acts as a means of eliminating bilirubin, a product of hemoglobin metabolism, from the body.


title: Gallbladder

text: The bile that is secreted by the liver and stored in the gallbladder is not the same as the bile that is secreted by the gallbladder. During gallbladder storage of bile, it is concentrated 3-10 fold by removal of some water and electrolytes. This is through the active transport of sodium and chloride ions across the epithelium of the gallbladder, which creates an osmotic pressure that also causes water and other electrolytes to be reabsorbed.


title: Gallbladder

text: Gallstones form when the bile is saturated, usually with either cholesterol or bilirubin. Most gallstones do not cause symptoms, with stones either remaining in the gallbladder or passed along the biliary system. When symptoms occur, severe "colicky" pain in the upper right part of the abdomen is often felt. If the stone blocks the gallbladder, inflammation known as cholecystitis may result. If the stone lodges in the biliary system, jaundice may occur; if the stone blocks the pancreatic duct, pancreatitis may occur. Gallstones are diagnosed using ultrasound. When a symptomatic gallstone occurs, it is often managed by waiting for it to be passed naturally. Given the likelihood of recurrent gallstones, surgery to remove the gallbladder is often considered. Some medication, such as ursodeoxycholic acid, may be used; lithotripsy, a non-invasive mechanical procedure used to break down the stones, may also be used.


title: Gallbladder

text: Known as cholecystitis, inflammation of the gallbladder is commonly caused by obstruction of the duct with gallstones, which is known as cholelithiasis. Blocked bile accumulates, and pressure on the gallbladder wall may lead to the release of substances that cause inflammation, such as phospholipase. There is also the risk of bacterial infection. An inflamed gallbladder is likely to cause sharp and localised pain, fever, and tenderness in the upper, right corner of the abdomen, and may have a positive Murphy's sign. Cholecystitis is often managed with rest and antibiotics, particularly cephalosporins and, in severe cases, metronidazole. Additionally the gallbladder may need to be removed surgically if inflammation has progressed far enough.


title: Gallbladder

text: A cholecystectomy is a procedure in which the gallbladder is removed. It may be removed because of recurrent gallstones and is considered an elective procedure. A cholecystectomy may be an open procedure, or a laparoscopic one. In the surgery, the gallbladder is removed from the neck to the fundus, and so bile will drain directly from the liver into the biliary tree. About 30 percent of patients may experience some degree of indigestion following the procedure, although severe complications are much rarer. About 10 percent of surgeries lead to a chronic condition of postcholecystectomy syndrome.


title: Gallbladder

text: Biliary injury (bile duct injury) is the traumatic damage of the bile ducts. It is most commonly an iatrogenic complication of cholecystectomy — surgical removal of gall bladder, but can also be caused by other operations or by major trauma. The risk of biliary injury is more during laparoscopic cholecystectomy than during open cholecystectomy. Biliary injury may lead to several complications and may even cause death if not diagnosed in time and managed properly. Ideally biliary injury should be managed at a center with facilities and expertise in endoscopy, radiology and surgery.


title: Gallbladder

text: Biloma is collection of bile within the abdominal cavity. It happens when there is a bile leak, for example after surgery for removing the gallbladder (laparoscopic cholecystectomy), with an incidence of 0.3–2%. Other causes are biliary surgery, liver biopsy, abdominal trauma, and, rarely, spontaneous perforation.


title: Gallbladder

text: Cancer of the gallbladder is uncommon and mostly occurs in later life. When cancer occurs, it is mostly of the glands lining the surface of the gallbladder (adenocarcinoma). Gallstones are thought to be linked to the formation of cancer. Other risk factors include large (>1 cm) gallbladder polyps and having a highly calcified "porcelain" gallbladder.


title: Gallbladder

text: Cancer of the gallbladder can cause attacks of biliary pain, yellowing of the skin (jaundice), and weight loss. A large gallbladder may be able to be felt in the abdomen. Liver function tests may be elevated, particularly involving GGT and ALP, with ultrasound and CT scans being considered medical imaging investigations of choice. Cancer of the gallbladder is managed by removing the gallbladder, however, the prognosis remains poor.


title: Gallbladder

text: Cancer of the gallbladder may also be found incidentally after surgical removal of the gallbladder, with 1–3% of cancers identified in this way. Gallbladder polyps are mostly benign growths or lesions resembling growths that form in the gallbladder wall, and are only associated with cancer when they are larger in size (>1 cm). Cholesterol polyps, often associated with cholesterolosis ("strawberry gallbladder", a change in the gallbladder wall due to excess cholesterol), often cause no symptoms and are thus often detected in this way.


title: Gallbladder

text: Tests used to investigate for gallbladder disease include blood tests and medical imaging. A full blood count may reveal an increased white cell count suggestive of inflammation or infection. Tests such as bilirubin and liver function tests may reveal if there is inflammation linked to the biliary tree or gallbladder, and whether this is associated with inflammation of the liver, and a lipase or amylase may be elevated if there is pancreatitis. Bilirubin may rise when there is obstruction of the flow of bile. A CA 19-9 level may be taken to investigate for cholangiocarcinoma.


title: Gallbladder

text: An ultrasound is often the first medical imaging test performed when gallbladder disease such as gallstones are suspected. An abdominal X-ray or CT scan is another form of imaging that may be used to examine the gallbladder and surrounding organs. Other imaging options include MRCP (magnetic resonance cholangiopancreatography), ERCP and percutaneous or intraoperative cholangiography. A cholescintigraphy scan is a nuclear imaging procedure used to assess the condition of the gallbladder.


title: Gallbladder

text: Most vertebrates have gallbladders, but the form and arrangement of the bile ducts may vary considerably. In many species, for example, there are several separate ducts running to the intestine, rather than the single common bile duct found in humans. Several species of mammals (including horses, deer, rats, and laminoids), several species of birds (such as pigeons and some psittacine species), lampreys and all invertebrates do not have a gallbladder.


title: Gallbladder

text: The bile from several species of bears is used in traditional Chinese medicine; bile bears are kept alive in captivity while their bile is extracted, in an industry characterized by animal cruelty.


title: Gallbladder

text: Depictions of the gallbladder and biliary tree are found in Babylonian models found from 2000 BCE, and in ancient Etruscan model from 200 BCE, with models associated with divine worship.


title: Gallbladder

text: Diseases of the gallbladder are known to have existed in humans since antiquity, with gallstones found in the mummy of Princess Amenen of Thebes dating to 1500 BCE. Some historians believe the death of Alexander the Great may have been associated with an acute episode of cholecystitis. The existence of the gallbladder has been noted since the 5th century, but it is only relatively recently that the function and the diseases of the gallbladder has been documented, particularly in the last two centuries.


title: Gallbladder

text: The first descriptions of gallstones appear to have been in the Renaissance, perhaps because of the low incidence of gallstones in earlier times owing to a diet with more cereals and vegetables and less meat. Anthonius Benevinius in 1506 was the first to draw a connection between symptoms and the presence of gallstones. Ludwig Georg Courvoisier, after examining a number of cases in 1890 that gave rise to the eponymous Courvoisier's law, stated that in an enlarged, nontender gallbladder, the cause of jaundice is unlikely to be gallstones.


title: Gallbladder

text: The first surgical removal of a gallstone (cholecystolithotomy) was in 1676 by physician Joenisius, who removed the stones from a spontaneously occurring biliary fistula. Stough Hobbs in 1867 performed the first recorded cholecystotomy, although such an operation was in fact described earlier by French surgeon Jean Louis Petit in the mid eighteenth century. German surgeon Carl Langenbuch performed the first cholecystectomy in 1882 for a sufferer of cholelithiasis. Before this, surgery had focused on creating a fistula for drainage of gallstones. Langenbuch reasoned that given several other species of mammal have no gallbladder, humans could survive without one.


title: Gallbladder

text: The debate whether surgical removal of the gallbladder or simply gallstones was preferred was settled in the 1920s, with the consensus that removal of the gallbladder was preferred. It was only in the mid and late parts of the twentieth century that medical imaging techniques such as use of contrast medium and CT scans were used to view the gallbladder. The first laparoscopic cholecystectomy performed by Erich Mühe of Germany in 1985, although French surgeons Phillipe Mouret and Francois Dubois are often credited for their operations in 1987 and 1988 respectively.


title: Gallbladder

text: To have "gall" is associated with bold behaviour, whereas to have "bile" is associated with bitterness.


title: Gallbladder

text: In the Chinese language, the gallbladder () is associated with courage and a myriad of related idioms, including using terms such as "a body completely [of] gall" () to describe a brave person, and "single gallbladder hero" () to describe a lone hero.


title: Gallbladder

text: In the Zangfu theory of Chinese medicine, the gallbladder not only has a digestive role, but is seen as the seat of decision-making.


title: Wellerman

text: "Soon May the Wellerman Come", also known as "Wellerman" or "The Wellerman", is a sea ballad from New Zealand first documented in the 1960s. The song refers to the "wellermen", pointing to supply ships owned by the Weller brothers, who were amongst the earliest European settlers of Otago.


title: Wellerman

text: In early 2021, a cover by Scottish singer Nathan Evans became a viral hit on the social media site TikTok, leading to a "social media craze" around sea shanties and maritime songs.


title: Wellerman

text: The history of whaling in New Zealand stretches from the late eighteenth century to 1965. In 1831, the British-born Weller brothers Edward, George and Joseph, who had emigrated to Sydney in 1829, founded a whaling station at Otakou near modern Dunedin in the South Island of New Zealand, seventeen years before Dunedin was established. Speaking at centennial celebrations in 1931, New Zealand's Governor General Lord Bledisloe recalled how the Weller brothers had on their voyage to New Zealand "brought in the 'Lucy Ann' (the Weller brothers' barque) a good deal of rum and a good deal of gunpowder...and some at least were rum characters". From 1833, the Weller brothers sold provisions to whalers in New Zealand from their base at Otakou, which they had named "Otago" in approximation of the local Māori pronunciation. Their employees became known as "wellermen". Unlike whaling in the Atlantic and northern Pacific, whalers in New Zealand practised shore-based whaling which required them to process the whale carcasses on land. The industry drew whalers to New Zealand from a diverse range of backgrounds encompassing not just the British Isles but also Indigenous peoples of the Americas, Pacific Islanders and Indigenous Australians. The whalers depended on good relations with the local Māori people and the whaling industry integrated Māori into the global economy and produced hundreds of intermarriages between whalers and local Māori, including Edward Weller himself, who was twice married to Māori women, thus linking the Wellers to one of the most prominent local Māori families, the Ellisons.


title: Wellerman

text: At its peak in 1834, the Otakou station was producing 310 tons of whale oil a year and became the centre of a network of seven stations that formed a highly profitable enterprise for the Wellers, employing as many as 85 people at Otago alone. From the Otakou base the Wellers branched out into industries as diverse as "timber, spars, flax, potatoes, dried fish, Māori artefacts, and even tattooed Māori heads which were in keen demand in Sydney". However, given that the Colony of New Zealand would not be declared until 1840, the Wellers were treated as foreign traders and were affected by protectionist British import tariffs on whale oil. By 1835, the year that Joseph Weller died in Otago, the brothers became convinced of the need to abandon the station even as they branched out into massive land purchases in New Zealand, which amounted to nearly by 1840. The Weller brothers' success in the whaling industry was fleeting, and they were declared bankrupt in 1840 after failed attempts at large-scale land purchase in New South Wales. The Otakou station closed in 1841. In 1841, the Court of Claims in New South Wales ruled that the Weller brothers' purchases of land in New Zealand were legally invalid, after which the Wellers "slipped unobtrusively out of the pages of New Zealand history". Commercial whaling in New Zealand continued until the 1960s.


title: Wellerman

text: The song's lyrics describe a whaling ship called the "Billy o' Tea" and its hunt for a right whale. The song describes how the ship's crew hope for a "wellerman" to arrive and bring them supplies of luxuries. According to the song's listing on the website "New Zealand Folk Song", "the workers at these bay-whaling stations (shore whalers) were not paid wages, they were paid in slops (ready made clothing), spirits and tobacco." The chorus continues with the crew singing of their confidence that the "tonguin'" will be the last step of their plight. Tonguing in this context refers to the practice of cutting strips of whale blubber to render into oil. Subsequent verses detail the captain's determination to bring in the whale in question, even as time passes and the quartet of whaling boats is lost in the fight. In the last verse, the narrator conveys how the "Billy o' Tea" is still considered locked in an ongoing struggle with the whale, with the wellerman making "his regular call" to strengthen the captain and crew.


title: Wellerman

text: New Zealand-based music teacher and folk music compiler Neil Colquhoun claimed to have collected the song around 1966 from one F. R. Woods. Woods, who was in his 80s at the time, had allegedly heard the song, as well as the song "John Smith A.B.", from his uncle. The song "John Smith A.B." was printed in a 1904 issue of "The Bulletin", where it was attributed to one D.H. Rogers. David Hunter Rogers was a first-generation Scottish immigrant who worked in the Union Company beginning in 1880; Wellerman does not resemble "John Smith A.B." or his other published poems. In 1973, "Soon May the Wellerman Come" was included in Colquhoun's book of New Zealand folk songs, "New Zealand Folksongs: Songs of a Young Country".


title: Wellerman

text: The song has been frequently performed and remixed, with over 10 recorded renditions between 1971 and 2005. In 1990, the New England-based folk trio of Gordon Bok, Ann Mayo Muir, and Ed Trickett recorded and released a version on their studio album "And So Will We Yet," produced by Folk-Legacy Records of Sharon, Connecticut. In 2013, the Wellington Sea Shanty Society released a version of the song on their album "Now That's What I Call Sea Shanties Vol. 1". A particularly well-known rendition of the song was made by the Bristol-based a cappella musical group the Longest Johns on their collection of nautical songs "Between Wind and Water" in 2018. In the wake of the "ShantyTok" social media sensation in 2021, Wellington Sea Shanty Society member Lake Davineer remarked that their recording had experienced a new burst of popularity.


title: Wellerman

text: The version of the song recorded by English folk group the Longest Johns (under the name "Wellerman") was not well known. The song features as the third track on the group's second studio album, "Between Wind and Water" (2018). A remix of the song was released on January 12, 2021.


title: Wellerman

text: A version by Scottish musician Nathan Evans further increased the song's exposure. Popularized as a sea shanty despite being more accurately described as a ballad, there was a surge in interest in sea shanties and a multitude of remixes and new versions. Evans's version has been praised for its "authentic sense of stoic forbearance" that has appealed to young people in lockdown during the COVID-19 pandemic, who like 19th-century whalers "are similarly marking time". In the "Rolling Stone" article discussing his success, Evans cited The Albany Shantymen version of the song as inspiration.  Because of its origins on TikTok, the trend of performing sea shanties like "Soon May the Wellerman Come" on social media has been called "ShantyTok". The song, jointly credited to Nathan Evans and remixers 220 Kid and Billen Ted by the Official Charts Company (OCC), reached number one on the UK Singles Chart. A new version of "Wellerman" with German folk band Santiano was released as a single on 19 February 2021. This version was included on the track listing of Santiano's EP "Sea Shanties – Wellerman", which was released digitally on 26 February 2021.


title: Wellerman

text: In February 2021, Evans, 220 Kid, and Billen Ted performed the song for the CBBC television programme "Blue Peter". In March 2021, Evans performed the song for the "End of the Show Show" segment on "Ant & Dec's Saturday Night Takeaway" Soon When the Saturday Come along with the programme's presenters. The performance included altered lyrics for the occasion and was accompanied by video footage of sing-alongs by celebrities, including Joan Collins, Josh Groban, Laura Whitmore and Dermot O'Leary. Crew members of the Royal National Lifeboat Institution, including those from Portishead and Sheringham, also submitted video for the performance, and Queen guitarist Brian May provided a guitar solo. In the seven countries where the remix has reached the top of the record charts, 200 non-fungible tokens were sold, which each include a new dance track, digital art, and a password redeemable for a future asset, with part of their proceeds going to the Royal National Lifeboat Institution and a scholarship by 220 Kid.


title: Wellerman

text: The version sparked multiple parodies, both on and off TikTok, including a Taylor Swift hit sung to the tune of Evans' version of "Wellerman" performed by the United States Navy Band, a Roman Catholic priest who changed the shanty's lyrics to explain Ash Wednesday, and a parody called "Waiting for the Vaccine" by Rainer Hersch.


title: Wellerman

text: In April 2022, Evans helped publicise the "Doctor Who" story "Legend of the Sea Devils" with an adaptation of "Wellerman".


title: Dichen Lachman

text: Dichen Lachman (; born 22 February 1982) is an Australian actress. She earned recognition starring as Katya Kinski in the soap opera "Neighbours" (2005–2007) and as Sierra in Joss Whedon's science fiction drama series "Dollhouse" (2009–2010).


title: Dichen Lachman

text: Lachman went on to portray Suren in the supernatural comedy-drama series "Being Human" (2012), Tani Tumrenjack in the military action-drama series "Last Resort" (2012–2013), Jiaying in the superhero drama series "Agents of S.H.I.E.L.D." (2014–2020), Reileen Kawahara in the cyberpunk drama series "Altered Carbon" (2018–2020), Frankie in the crime drama series "Animal Kingdom" (2018–present), and Ms. Casey in the thriller series "Severance" (2022–present).


title: Dichen Lachman

text: Lachman has appeared in numerous films, such as "Aquamarine" (2006), "Bled" (2009), "Lust for Love" (2014), "Too Late" (2015), "Bad Therapy" (2020), and "Jurassic World Dominion" (2022).


title: Dichen Lachman

text: Lachman was born in Kathmandu, Nepal. She moved to Adelaide, Australia, in the early 1990s with her family.


title: Dichen Lachman

text: Her mother is Tibetan, and her Australian father is of German descent. She attended West Lakes Primary School, Gilles Street Primary School, Norwood Morialta High School, St Mary's College, Adelaide, Annesley College and the University of Adelaide. She moved to Los Angeles shortly after she finished with the Australian TV drama "Neighbours" in 2007.


title: Dichen Lachman

text: Lachman first filmed an ad in Australia for Wanadoo, which aired in the United Kingdom. In 2005, she joined the cast of the Australian soap opera "Neighbours" as Katya Kinski. She had auditioned for the role of Elle Robinson, but the producers decided to create the part of Katya for her.


title: Dichen Lachman

text: Lachman played a small role in the feature film "Aquamarine". After she finished shooting the role of Aaren in the film "Bled", Lachman joined the cast of the film "Aztec Rex" in Hawaii. In an interview with "The Soap Show", Lachman said she had appeared on the BBC television show "Ready Steady Cook" while visiting England in late 2006. In the interview, she explained that she was in Los Angeles to advance her acting career, but said she would love to work in the UK and Australia.


title: Dichen Lachman

text: On 26 March 2008, it was announced that Lachman would portray Sierra in the television series "Dollhouse", created by Joss Whedon.


title: Dichen Lachman

text: In an interview with ScifiNow in 2009, Lachman responded to the rumor that she would star in an upcoming television show based on "Star Wars" by saying, "I am a huge George Lucas fan. I love those movies and it would be a dream come true—I'd love to do it, it would be incredible." She was named one of the 100 hottest women on screen for 2009, by the lesbian media site AfterEllen.com. "What a privilege to be there," she said.


title: Dichen Lachman

text: She guest starred as an insurance agent/street racer on "". She also appeared as Amy Hanamoa, the widow of a murdered police officer, in an episode of "Hawaii Five-0". Lachman made a guest appearance in an episode of the "Doctor Who" spin-off "Torchwood", for its fourth series "". Additionally, in 2011 it was announced in "Variety" that Lachman would be joining the cast of "Being Human" as a series regular. Lachman also made a brief appearance in the web-series "The Guild" during Season 5, episode 8 as a party guest during a gaming convention.


title: Dichen Lachman

text: In 2012, it was announced Lachman would be joining the Shawn Ryan–driven pilot "Last Resort" for ABC, and she subsequently appeared as a main character during the show's 13-episode run. She also guest starred in the second season of the Jane Espenson scripted web series, "Husbands".


title: Dichen Lachman

text: Between 2010 and 2013, while working on other productions, Lachman and her close friend Anton King produced "Lust for Love". King wrote the script in 2010 and used Kickstarter to raise funds to make the movie. The initial goal was to raise US$70,000; however, when the deadline was reached on 11 November 2011 more than 1,500 people had pledged money, with a final figure of US$101,030. To complete the movie, additional funds were raised through friends and family. British filmmaker Jack Wylson came on board as a producer, Australian actor Adam J. Yeend as co-producer, and Adam Bricker as director of photography. Alessandro Ongaro of Luna Pictures Entertainment also made major contributions during post production.


title: Dichen Lachman

text: In 2014, Lachman began shooting in Canada, where she joined the cast of "The 100" in the role of Anya and had a recurring role on ABC's "Agents of S.H.I.E.L.D."


title: Dichen Lachman

text: On 11 June 2015, a new movie called "Too Late", starring Lachman, was released during the Los Angeles Film Festival. On 22 October 2015, it was announced that Lachman landed a recurring role on the third season of Michael Bay's action-adventure TNT series "The Last Ship". Lachman had been cast as Jesse, a helicopter pilot who lives off-the-grid. She starred as Reileen Kawahara in Netflix's original television series, "Altered Carbon", an adaptation of the 2002 novel of the same name by Richard K. Morgan. The first season was released on 2 February 2018. Also, starting in 2018, Lachman began a recurring role as Frankie on "Animal Kingdom" during its third season.


title: Dichen Lachman

text: In 2020, she returned for small story arcs on "Agents of S.H.I.E.L.D." and "Altered Carbon", and she also appeared in the film "Bad Therapy". In 2022, Lachman joined the main cast of "Severance", which premiered on Apple TV+. She appeared as Ms. Casey, a wellness counselor. The series received acclaim from critics and audiences, with Lachman being nominated for Best Supporting Actress in a Streaming Series, Drama at the 2nd Hollywood Critics Association TV Awards. Soon after she appeared as antagonist Soyona Santos in the film "Jurassic World Dominion". Lachman was then announced as the titular character in Steven Brand's noir thriller "Joe Baby".


title: Dichen Lachman

text: She has been married to Austrian-born American actor Maximilian Osinski since January 2015, and gave birth to their daughter that May.


title: Thermonuclear weapon

text: A thermonuclear weapon, fusion weapon or hydrogen bomb (H bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lower mass, or a combination of these benefits. Characteristics of nuclear fusion reactions make possible the use of non-fissile depleted uranium as the weapon's main fuel, thus allowing more efficient use of scarce fissile material such as uranium-235 () or plutonium-239 (). The first full-scale thermonuclear test was carried out by the United States in 1952; the concept has since been employed by most of the world's nuclear powers in the design of their weapons.


title: Thermonuclear weapon

text: Modern fusion weapons consist essentially of two main components: a nuclear fission primary stage (fueled by or ) and a separate nuclear fusion secondary stage containing thermonuclear fuel: the heavy hydrogen isotopes deuterium and tritium, or in modern weapons lithium deuteride. For this reason, thermonuclear weapons are often colloquially called hydrogen bombs or H-bombs.


title: Thermonuclear weapon

text: A fusion explosion begins with the detonation of the fission primary stage. Its temperature soars past approximately 100 million kelvin, causing it to glow intensely with thermal X-rays. These X-rays flood the void (the "radiation channel" often filled with polystyrene foam) between the primary and secondary assemblies placed within an enclosure called a radiation case, which confines the X-ray energy and resists its outward pressure. The distance separating the two assemblies ensures that debris fragments from the fission primary (which move much more slowly than X-ray photons) cannot disassemble the secondary before the fusion explosion runs to completion.


title: Thermonuclear weapon

text: The secondary fusion stage—consisting of outer pusher/tamper, fusion fuel filler and central plutonium spark plug—is imploded by the X-ray energy impinging on its pusher/tamper. This compresses the entire secondary stage and drives up the density of the plutonium spark plug. The density of the plutonium fuel rises to such an extent that the spark plug is driven into a supercritical state, and it begins a nuclear fission chain reaction. The fission products of this chain reaction heat the highly compressed, and thus super dense, thermonuclear fuel surrounding the spark plug to around 300 million kelvin, igniting fusion reactions between fusion fuel nuclei. In modern weapons fueled by lithium deuteride, the fissioning plutonium spark plug also emits free neutrons which collide with lithium nuclei and supply the tritium component of the thermonuclear fuel.


title: Thermonuclear weapon

text: The secondary's relatively massive tamper (which resists outward expansion as the explosion proceeds) also serves as a thermal barrier to keep the fusion fuel filler from becoming too hot, which would spoil the compression. If made of uranium, enriched uranium or plutonium, the tamper captures fast fusion neutrons and undergoes fission itself, increasing the overall explosive yield. Additionally, in most designs the radiation case is also constructed of a fissile material that undergoes fission driven by fast thermonuclear neutrons. Such bombs are classified as two stage weapons, and most current Teller–Ulam designs are such fission-fusion-fission weapons. Fast fission of the tamper and radiation case is the main contribution to the total yield and is the dominant process that produces radioactive fission product fallout.


title: Thermonuclear weapon

text: Before Ivy Mike, Operation Greenhouse of 1951 was the first American nuclear test series to test principles that led to the development of thermonuclear weapons. Sufficient fission was achieved to boost the associated fusion device, and enough was learned to achieve a full-scale device within a year. The design of all modern thermonuclear weapons in the United States is known as the "Teller–Ulam configuration" for its two chief contributors, Edward Teller and Stanislaw Ulam, who developed it in 1951 for the United States, with certain concepts developed with the contribution of physicist John von Neumann. Similar devices were developed by the Soviet Union, United Kingdom, France, and China. The thermonuclear Tsar Bomba was the most powerful bomb ever tested.


title: Thermonuclear weapon

text: As thermonuclear weapons represent the most efficient design for weapon energy yield in weapons with yields above , virtually all the nuclear weapons of this size deployed by the five nuclear-weapon states under the Non-Proliferation Treaty today are thermonuclear weapons using the Teller–Ulam design.


title: Thermonuclear weapon

text: Detailed knowledge of fission and fusion weapons is classified to some degree in virtually every industrialized nation. In the United States, such knowledge can by default be classified as "Restricted Data", even if it is created by persons who are not government employees or associated with weapons programs, in a legal doctrine known as "born secret" (though the constitutional standing of the doctrine has been at times called into question; see "United States v. Progressive, Inc."). Born secret is rarely invoked for cases of private speculation. The official policy of the United States Department of Energy has been not to acknowledge the leaking of design information, as such acknowledgment would potentially validate the information as accurate. In a small number of prior cases, the U.S. government has attempted to censor weapons information in the public press, with limited success. According to the "New York Times", physicist Kenneth W. Ford defied government orders to remove classified information from his book, "Building the H Bomb: A Personal History". Ford claims he used only pre-existing information and even submitted a manuscript to the government, which wanted to remove entire sections of the book for concern that foreign nations could use the information.


title: Thermonuclear weapon

text: Though large quantities of vague data have been officially released, and larger quantities of vague data have been unofficially leaked by former bomb designers, most public descriptions of nuclear weapon design details rely to some degree on speculation, reverse engineering from known information, or comparison with similar fields of physics (inertial confinement fusion is the primary example). Such processes have resulted in a body of unclassified knowledge about nuclear bombs that is generally consistent with official unclassified information releases, related physics, and is thought to be internally consistent, though there are some points of interpretation that are still considered open. The state of public knowledge about the Teller–Ulam design has been mostly shaped from a few specific incidents outlined in a section below.


title: Thermonuclear weapon

text: The basic principle of the Teller–Ulam configuration is the idea that different parts of a thermonuclear weapon can be chained together in "stages", with the detonation of each stage providing the energy to ignite the next stage. At a bare minimum, this implies a "primary" section that consists of an implosion-type fission bomb (a "trigger"), and a "secondary" section that consists of fusion fuel. The energy released by the "primary" compresses the "secondary" through a process called "radiation implosion", at which point it is heated and undergoes nuclear fusion. This process could be continued, with energy from the secondary igniting a third fusion stage; Russia's AN602 "Tsar Bomba" is thought to have been a three-stage fission-fusion-fusion device. Theoretically by continuing this process thermonuclear weapons with arbitrarily high yield could be constructed. This contrasts with fission weapons which are limited in yield because only so much fission fuel can be amassed in one place before the danger of its accidentally becoming supercritical becomes too great.


title: Thermonuclear weapon

text: Surrounding the other components is a hohlraum or "radiation case", a container that traps the first stage or primary's energy inside temporarily. The outside of this radiation case, which is also normally the outside casing of the bomb, is the only direct visual evidence publicly available of any thermonuclear bomb component's configuration. Numerous photographs of various thermonuclear bomb exteriors have been declassified.


title: Thermonuclear weapon

text: The primary is thought to be a standard implosion method fission bomb, though likely with a core boosted by small amounts of fusion fuel (usually 50/50% deuterium/tritium gas) for extra efficiency; the fusion fuel releases excess neutrons when heated and compressed, inducing additional fission. When fired, the or core would be compressed to a smaller sphere by special layers of conventional high explosives arranged around it in an explosive lens pattern, initiating the nuclear chain reaction that powers the conventional "atomic bomb".


title: Thermonuclear weapon

text: The secondary is usually shown as a column of fusion fuel and other components wrapped in many layers. Around the column is first a "pusher-tamper", a heavy layer of uranium-238 () or lead that helps compress the fusion fuel (and, in the case of uranium, may eventually undergo fission itself). Inside this is the fusion fuel itself, usually a form of lithium deuteride, which is used because it is easier to weaponize than liquefied tritium/deuterium gas. This dry fuel, when bombarded by neutrons, produces tritium, a heavy isotope of hydrogen which can undergo nuclear fusion, along with the deuterium present in the mixture. (See the article on nuclear fusion for a more detailed technical discussion of fusion reactions.) Inside the layer of fuel is the "spark plug", a hollow column of fissile material ( or ) often boosted by deuterium gas. The spark plug, when compressed, can itself undergo nuclear fission (because of the shape, it is not a critical mass without compression). The tertiary, if one is present, would be set below the secondary and probably be made of the same materials.


title: Thermonuclear weapon

text: Separating the secondary from the primary is the interstage. The fissioning primary produces four types of energy: 1) expanding hot gases from high explosive charges that implode the primary; 2) superheated plasma that was originally the bomb's fissile material and its tamper; 3) the electromagnetic radiation; and 4) the neutrons from the primary's nuclear detonation. The interstage is responsible for accurately modulating the transfer of energy from the primary to the secondary. It must direct the hot gases, plasma, electromagnetic radiation and neutrons toward the right place at the right time. Less than optimal interstage designs have resulted in the secondary failing to work entirely on multiple shots, known as a "fissile fizzle". The Castle Koon shot of Operation Castle is a good example; a small flaw allowed the neutron flux from the primary to prematurely begin heating the secondary, weakening the compression enough to prevent any fusion.


title: Thermonuclear weapon

text: There is very little detailed information in the open literature about the mechanism of the interstage. One of the best sources is a simplified diagram of a British thermonuclear weapon similar to the American W80 warhead. It was released by Greenpeace in a report titled ""Dual Use Nuclear Technology"". The major components and their arrangement are in the diagram, though details are almost absent; what scattered details it does include likely have intentional omissions or inaccuracies. They are labeled "End-cap and Neutron Focus Lens" and "Reflector Wrap"; the former channels neutrons to the / Spark Plug while the latter refers to an X-ray reflector; typically a cylinder made of an X-ray opaque material such as uranium with the primary and secondary at either end. It does not reflect like a mirror; instead, it gets heated to a high temperature by the X-ray flux from the primary, then it emits more evenly spread X-rays that travel to the secondary, causing what is known as radiation implosion. In Ivy Mike, gold was used as a coating over the uranium to enhance the blackbody effect. Next comes the "Reflector/Neutron Gun Carriage". The reflector seals the gap between the Neutron Focus Lens (in the center) and the outer casing near the primary. It separates the primary from the secondary and performs the same function as the previous reflector. There are about six neutron guns (seen here from Sandia National Laboratories) each protruding through the outer edge of the reflector with one end in each section; all are clamped to the carriage and arranged more or less evenly around the casing's circumference. The neutron guns are tilted so the neutron emitting end of each gun end is pointed towards the central axis of the bomb. Neutrons from each neutron gun pass through and are focused by the neutron focus lens towards the centre of primary in order to boost the initial fissioning of the plutonium. A "polystyrene Polarizer/Plasma Source" is also shown (see below).


title: Thermonuclear weapon

text: The first U.S. government document to mention the interstage was only recently released to the public promoting the 2004 initiation of the Reliable Replacement Warhead Program. A graphic includes blurbs describing the potential advantage of a RRW on a part by part level, with the interstage blurb saying a new design would replace "toxic, brittle material" and "expensive 'special' material... [which require] unique facilities". The "toxic, brittle material" is widely assumed to be beryllium which fits that description and would also moderate the neutron flux from the primary. Some material to absorb and re-radiate the X-rays in a particular manner may also be used.


title: Thermonuclear weapon

text: Candidates for the "special material" are polystyrene and a substance called "Fogbank", an unclassified codename. Fogbank's composition is classified, though aerogel has been suggested as a possibility. It was first used in thermonuclear weapons with the W76 thermonuclear warhead, and produced at a plant in the Y-12 Complex at Oak Ridge, Tennessee, for use in the W76. Production of Fogbank lapsed after the W76 production run ended. The W76 Life Extension Program required more Fogbank to be made. This was complicated by the fact that the original Fogbank's properties were not fully documented, so a massive effort was mounted to re-invent the process. An impurity crucial to the properties of the old Fogbank was omitted during the new process. Only close analysis of new and old batches revealed the nature of that impurity. The manufacturing process used acetonitrile as a solvent, which led to at least three evacuations of the Fogbank plant in 2006. Widely used in the petroleum and pharmaceutical industries, acetonitrile is flammable and toxic. Y-12 is the sole producer of Fogbank.


title: Thermonuclear weapon

text: The basic idea of the Teller–Ulam configuration is that each "stage" would undergo fission or fusion (or both) and release energy, much of which would be transferred to another stage to trigger it. How exactly the energy is "transported" from the "primary" to the "secondary" has been the subject of some disagreement in the open press, but is thought to be transmitted through the X-rays and Gamma rays that are emitted from the fissioning "primary". This energy is then used to compress the "secondary". The crucial detail of "how" the X-rays create the pressure is the main remaining disputed point in the unclassified press. There are three proposed theories:


title: Thermonuclear weapon

text: The radiation pressure exerted by the large quantity of X-ray photons inside the closed casing might be enough to compress the secondary. Electromagnetic radiation such as X-rays or light carries momentum and exerts a force on any surface it strikes. The pressure of radiation at the intensities seen in everyday life, such as sunlight striking a surface, is usually imperceptible, but at the extreme intensities found in a thermonuclear bomb the pressure is enormous.


title: Thermonuclear weapon

text: For two thermonuclear bombs for which the general size and primary characteristics are well understood, the Ivy Mike test bomb and the modern W-80 cruise missile warhead variant of the W-61 design, the radiation pressure was calculated to be for the Ivy Mike design and for the W-80.


title: Thermonuclear weapon

text: Foam plasma pressure is the concept that Chuck Hansen introduced during the Progressive case, based on research that located declassified documents listing special foams as liner components within the radiation case of thermonuclear weapons.


title: Thermonuclear weapon

text: This would complete the fission-fusion-fission sequence. Fusion, unlike fission, is relatively "clean"—it releases energy but no harmful radioactive products or large amounts of nuclear fallout. The fission reactions though, especially the last fission reactions, release a tremendous amount of fission products and fallout. If the last fission stage is omitted, by replacing the uranium tamper with one made of lead, for example, the overall explosive force is reduced by approximately half but the amount of fallout is relatively low. The neutron bomb is a hydrogen bomb with an intentionally thin tamper, allowing as many of the fast fusion neutrons as possible to escape.


title: Thermonuclear weapon

text: Current technical criticisms of the idea of "foam plasma pressure" focus on unclassified analysis from similar high energy physics fields that indicate that the pressure produced by such a plasma would only be a "small multiplier" of the basic photon pressure within the radiation case, and also that the known foam materials intrinsically have a very low absorption efficiency of the gamma ray and X-ray radiation from the primary. Most of the energy produced would be absorbed by either the walls of the radiation case or the tamper around the secondary. Analyzing the effects of that absorbed energy led to the third mechanism: ablation.


title: Thermonuclear weapon

text: The outer casing of the secondary assembly is called the "tamper-pusher". The purpose of a tamper in an implosion bomb is to delay the expansion of the reacting fuel supply (which is very hot dense plasma) until the fuel is fully consumed and the explosion runs to completion. The same tamper material serves also as a pusher in that it is the medium by which the outside pressure (force acting on the surface area of the secondary) is transferred to the mass of fusion fuel.


title: Thermonuclear weapon

text: The proposed tamper-pusher ablation mechanism posits that the outer layers of the thermonuclear secondary's tamper-pusher are heated so extremely by the primary's X-ray flux that they expand violently and ablate away (fly off). Because total momentum is conserved, this mass of high velocity ejecta impels the rest of the tamper-pusher to recoil inwards with tremendous force, crushing the fusion fuel and the spark plug. The tamper-pusher is built robustly enough to insulate the fusion fuel from the extreme heat outside; otherwise the compression would be spoiled.


title: Thermonuclear weapon

text: Rough calculations for the basic ablation effect are relatively simple: the energy from the primary is distributed evenly onto all of the surfaces within the outer radiation case, with the components coming to a thermal equilibrium, and the effects of that thermal energy are then analyzed. The energy is mostly deposited within about one X-ray optical thickness of the tamper/pusher outer surface, and the temperature of that layer can then be calculated. The velocity at which the surface then expands outwards is calculated and, from a basic Newtonian momentum balance, the velocity at which the rest of the tamper implodes inwards.


title: Thermonuclear weapon

text: Applying the more detailed form of those calculations to the Ivy Mike device yields vaporized pusher gas expansion velocity of and an implosion velocity of perhaps if of the total tamper/pusher mass is ablated off, the most energy efficient proportion. For the W-80 the gas expansion velocity is roughly and the implosion velocity . The pressure due to the ablating material is calculated to be in the Ivy Mike device and in the W-80 device.


title: Thermonuclear weapon

text: The calculated ablation pressure is one order of magnitude greater than the higher proposed plasma pressures and nearly two orders of magnitude greater than calculated radiation pressure. No mechanism to avoid the absorption of energy into the radiation case wall and the secondary tamper has been suggested, making ablation apparently unavoidable. The other mechanisms appear to be unneeded.


title: Thermonuclear weapon

text: United States Department of Defense official declassification reports indicate that foamed plastic materials are or may be used in radiation case liners, and despite the low direct plasma pressure they may be of use in delaying the ablation until energy has distributed evenly and a sufficient fraction has reached the secondary's tamper/pusher.


title: Thermonuclear weapon

text: Richard Rhodes' book "Dark Sun" stated that a layer of plastic foam was fixed to the lead liner of the inside of the Ivy Mike steel casing using copper nails. Rhodes quotes several designers of that bomb explaining that the plastic foam layer inside the outer case is to delay ablation and thus recoil of the outer case: if the foam were not there, metal would ablate from the inside of the outer case with a large impulse, causing the casing to recoil outwards rapidly. The purpose of the casing is to contain the explosion for as long as possible, allowing as much X-ray ablation of the metallic surface of the secondary stage as possible, so it compresses the secondary efficiently, maximizing the fusion yield. Plastic foam has a low density, so causes a smaller impulse when it ablates than metal does.


title: Thermonuclear weapon

text: Two special variations exist that will be discussed in a subsequent section: the cryogenically cooled liquid deuterium device used for the Ivy Mike test, and the putative design of the W88 nuclear warhead—a small, MIRVed version of the Teller–Ulam configuration with a prolate (egg or watermelon shaped) primary and an elliptical secondary.


title: Thermonuclear weapon

text: Most bombs do not apparently have tertiary "stages"—that is, third compression stage(s), which are additional fusion stages compressed by a previous fusion stage. (The fissioning of the last blanket of uranium, which provides about half the yield in large bombs, does not count as a "stage" in this terminology.)


title: Thermonuclear weapon

text: The U.S. tested three-stage bombs in several explosions (see Operation Redwing) but is thought to have fielded only one such tertiary model, i.e., a bomb in which a fission stage, followed by a fusion stage, finally compresses yet another fusion stage. This U.S. design was the heavy but highly efficient (i.e., nuclear weapon yield per unit bomb weight) B41 nuclear bomb. The Soviet Union is thought to have used multiple stages (including more than one tertiary fusion stage) in their ( in intended use) Tsar Bomba (however, as with other bombs, the fissionable jacket could be replaced with lead in such a bomb, and in this one, for demonstration, it was). If any hydrogen bombs have been made from configurations other than those based on the Teller–Ulam design, the fact of it is not publicly known. (A possible exception to this is the Soviet early "Sloika" design.)


title: Thermonuclear weapon

text: In essence, the Teller–Ulam configuration relies on at least two instances of implosion occurring: first, the conventional (chemical) explosives in the primary would compress the fissile core, resulting in a fission explosion many times more powerful than that which chemical explosives could achieve alone (first stage). Second, the radiation from the fissioning of the primary would be used to compress and ignite the secondary fusion stage, resulting in a fusion explosion many times more powerful than the fission explosion alone. This chain of compression could conceivably be continued with an arbitrary number of tertiary fusion stages, each igniting more fusion fuel in the next stage although this is debated (see more: Arbitrarily large yield debate). Finally, efficient bombs (but not so-called neutron bombs) end with the fissioning of the final natural uranium tamper, something that could not normally be achieved without the neutron flux provided by the fusion reactions in secondary or tertiary stages. Such designs are suggested to be capable of being scaled up to an arbitrary large yield (with apparently as many fusion stages as desired), potentially to the level of a "doomsday device." However, usually such weapons were not more than a dozen megatons, which was generally considered enough to destroy even the most hardened practical targets (for example, a control facility such as the Cheyenne Mountain Complex). Even such large bombs have been replaced by smaller-yield bunker buster type nuclear bombs (see more: nuclear bunker buster).


title: Thermonuclear weapon

text: As discussed above, for destruction of cities and non-hardened targets, breaking the mass of a single missile payload down into smaller MIRV bombs, in order to spread the energy of the explosions into a "pancake" area, is far more efficient in terms of area-destruction per unit of bomb energy. This also applies to single bombs deliverable by cruise missile or other system, such as a bomber, resulting in most operational warheads in the U.S. program having yields of less than .


title: Thermonuclear weapon

text: The idea of a thermonuclear fusion bomb ignited by a smaller fission bomb was first proposed by Enrico Fermi to his colleague Edward Teller when they were talking at Columbia University in September 1941, at the start of what would become the Manhattan Project. Teller spent much of the Manhattan Project attempting to figure out how to make the design work, preferring it to work on the atomic bomb, and over the last year of the project was assigned exclusively to the task. However once World War II ended, there was little impetus to devote many resources to the "Super", as it was then known.


title: Thermonuclear weapon

text: The first atomic bomb test by the Soviet Union in August 1949 came earlier than expected by Americans, and over the next several months there was an intense debate within the U.S. government, military, and scientific communities regarding whether to proceed with development of the far more powerful Super. The debate covered matters that were alternatively strategic, pragmatic, and moral. In their "Report of the General Advisory Committee," Robert Oppenheimer and colleagues concluded that "[t]he extreme danger to mankind inherent in the proposal [to develop thermonuclear weapons] wholly outweighs any military advantage." Despite the objections raised, on 31 January 1950, President Harry S. Truman made the decision to go forward with the development of the new weapon.


title: Thermonuclear weapon

text: But deciding to do it did not make it a reality, and Teller and other U.S. physicists struggled to find a workable design. Stanislaw Ulam, a co-worker of Teller, made the first key conceptual leaps towards a workable fusion design. Ulam's two innovations that rendered the fusion bomb practical were that compression of the thermonuclear fuel before extreme heating was a practical path towards the conditions needed for fusion, and the idea of staging or placing a separate thermonuclear component outside a fission primary component, and somehow using the primary to compress the secondary. Teller then realized that the gamma and X-ray radiation produced in the primary could transfer enough energy into the secondary to create a successful implosion and fusion burn, if the whole assembly was wrapped in a "hohlraum" or radiation case. Teller and his various proponents and detractors later disputed the degree to which Ulam had contributed to the theories underlying this mechanism. Indeed, shortly before his death, and in a last-ditch effort to discredit Ulam's contributions, Teller claimed that one of his own "graduate students" had proposed the mechanism.


title: Thermonuclear weapon

text: The "George" shot of Operation Greenhouse of 9 May 1951 tested the basic concept for the first time on a very small scale. As the first successful (uncontrolled) release of nuclear fusion energy, which made up a small fraction of the total yield, it raised expectations to a near certainty that the concept would work.


title: Thermonuclear weapon

text: On 1 November 1952, the Teller–Ulam configuration was tested at full scale in the "Ivy Mike" shot at an island in the Enewetak Atoll, with a yield of (over 450 times more powerful than the bomb dropped on Nagasaki during World War II). The device, dubbed the "Sausage", used an extra-large fission bomb as a "trigger" and liquid deuterium—kept in its liquid state by of cryogenic equipment—as its fusion fuel, and weighed around altogether.


title: Thermonuclear weapon

text: The liquid deuterium fuel of Ivy Mike was impractical for a deployable weapon, and the next advance was to use a solid lithium deuteride fusion fuel instead. In 1954 this was tested in the "Castle Bravo" shot (the device was code-named "Shrimp"), which had a yield of (2.5 times expected) and is the largest U.S. bomb ever tested.


title: Thermonuclear weapon

text: Efforts in the United States soon shifted towards developing miniaturized Teller–Ulam weapons that could fit into intercontinental ballistic missiles and submarine-launched ballistic missiles. By 1960, with the W47 warhead deployed on Polaris ballistic missile submarines, megaton-class warheads were as small as in diameter and in weight. Further innovation in miniaturizing warheads was accomplished by the mid-1970s, when versions of the Teller–Ulam design were created that could fit ten or more warheads on the end of a small MIRVed missile (see the section on the W88 below).


title: Thermonuclear weapon

text: The first Soviet fusion design, developed by Andrei Sakharov and Vitaly Ginzburg in 1949 (before the Soviets had a working fission bomb), was dubbed the "Sloika", after a Russian layer cake, and was not of the Teller–Ulam configuration. It used alternating layers of fissile material and lithium deuteride fusion fuel spiked with tritium (this was later dubbed Sakharov's "First Idea"). Though nuclear fusion might have been technically achievable, it did not have the scaling property of a "staged" weapon. Thus, such a design could not produce thermonuclear weapons whose explosive yields could be made arbitrarily large (unlike U.S. designs at that time). The fusion layer wrapped around the fission core could only moderately multiply the fission energy (modern Teller–Ulam designs can multiply it 30-fold). Additionally, the whole fusion stage had to be imploded by conventional explosives, along with the fission core, substantially multiplying the amount of chemical explosives needed.


title: Thermonuclear weapon

text: The first Sloika design test, RDS-6s, was detonated in 1953 with a yield equivalent to ( from fusion). Attempts to use a "Sloika" design to achieve megaton-range results proved unfeasible. After the United States tested the "Ivy Mike" thermonuclear device in November 1952, proving that a multimegaton bomb could be created, the Soviets searched for an alternative design. The "Second Idea", as Sakharov referred to it in his memoirs, was a previous proposal by Ginzburg in November 1948 to use lithium deuteride in the bomb, which would, in the course of being bombarded by neutrons, produce tritium and free deuterium. In late 1953 physicist Viktor Davidenko achieved the first breakthrough, that of keeping the "primary" and "secondary" parts of the bombs in separate pieces ("staging"). The next breakthrough was discovered and developed by Sakharov and Yakov Zel'dovich, that of using the X-rays from the fission bomb to compress the "secondary" before fusion ("radiation implosion"), in early 1954. Sakharov's "Third Idea", as the Teller–Ulam design was known in the USSR, was tested in the shot "RDS-37" in November 1955 with a yield of .


title: Thermonuclear weapon

text: The Soviets demonstrated the power of the "staging" concept in October 1961, when they detonated the massive and unwieldy "Tsar Bomba", a hydrogen bomb that derived almost of its energy from fusion. It was the largest nuclear weapon developed and tested by any country.


title: Thermonuclear weapon

text: In 1954 work began at Aldermaston to develop the British fusion bomb, with Sir William Penney in charge of the project. British knowledge on how to make a thermonuclear fusion bomb was rudimentary, and at the time the United States was not exchanging any nuclear knowledge because of the Atomic Energy Act of 1946. However, the British were allowed to observe the U.S. Castle tests and used sampling aircraft in the mushroom clouds, providing them with clear, direct evidence of the compression produced in the secondary stages by radiation implosion.


title: Thermonuclear weapon

text: Because of these difficulties, in 1955 British prime minister Anthony Eden agreed to a secret plan, whereby if the Aldermaston scientists failed or were greatly delayed in developing the fusion bomb, it would be replaced by an extremely large fission bomb.


title: Thermonuclear weapon

text: In 1957 the Operation Grapple tests were carried out. The first test, Green Granite, was a prototype fusion bomb, but failed to produce equivalent yields compared to the U.S. and Soviets, achieving only approximately . The second test Orange Herald was the modified fission bomb and produced —making it the largest fission explosion ever. At the time almost everyone (including the pilots of the plane that dropped it) thought that this was a fusion bomb. This bomb was put into service in 1958. A second prototype fusion bomb, Purple Granite, was used in the third test, but only produced approximately .


title: Thermonuclear weapon

text: A second set of tests was scheduled, with testing recommencing in September 1957. The first test was based on a "… new simpler design. A two stage thermonuclear bomb that had a much more powerful trigger". This test Grapple X Round C was exploded on 8 November and yielded approximately . On 28 April 1958 a bomb was dropped that yielded —Britain's most powerful test. Two final air burst tests on 2 September – 11 September 1958, dropped smaller bombs that yielded around each.


title: Thermonuclear weapon

text: American observers had been invited to these kinds of tests. After Britain's successful detonation of a megaton-range device (and thus demonstrating a practical understanding of the Teller–Ulam design "secret"), the United States agreed to exchange some of its nuclear designs with the United Kingdom, leading to the 1958 US–UK Mutual Defence Agreement. Instead of continuing with its own design, the British were given access to the design of the smaller American Mk 28 warhead and were able to manufacture copies.


title: Thermonuclear weapon

text: The United Kingdom had worked closely with the Americans on the Manhattan Project. British access to nuclear weapons information was cut off by the United States at one point due to concerns about Soviet espionage. Full cooperation was not reestablished until an agreement governing the handling of secret information and other issues was signed.


title: Thermonuclear weapon

text: Mao Zedong decided to begin a Chinese nuclear-weapons program during the First Taiwan Strait Crisis of 1954–1955. The People's Republic of China detonated its first hydrogen (thermonuclear) bomb on 17 June 1967, 32 months after detonating its first fission weapon, with a yield of 3.31 Mt. It took place in the Lop Nor Test Site, in northwest China. China had received extensive technical help from the Soviet Union to jump-start their nuclear program, but by 1960, the rift between the Soviet Union and China had become so great that the Soviet Union ceased all assistance to China.


title: Thermonuclear weapon

text: A story in "The New York Times" by William Broad reported that in 1995, a supposed Chinese double agent delivered information indicating that China knew secret details of the U.S. W88 warhead, supposedly through espionage. (This line of investigation eventually resulted in the abortive trial of Wen Ho Lee.)


title: Thermonuclear weapon

text: The French nuclear testing site was moved to the unpopulated French atolls in the Pacific Ocean. The first test conducted at these new sites was the "Canopus" test in the Fangataufa atoll in French Polynesia on 24 August 1968, the country's first multistage thermonuclear weapon test. The bomb was detonated from a balloon at a height of . The result of this test was significant atmospheric contamination. Very little is known about France's development of the Teller–Ulam design, beyond the fact that France detonated a device in the "Canopus" test. France reportedly had great difficulty with its initial development of the Teller-Ulam design, but it later overcame these, and is believed to have nuclear weapons equal in sophistication to the other major nuclear powers.


title: Thermonuclear weapon

text: France and China did not sign or ratify the Partial Nuclear Test Ban Treaty of 1963, which banned nuclear test explosions in the atmosphere, underwater, or in outer space. Between 1966 and 1996 France carried out more than 190 nuclear tests. France's final nuclear test took place on 27 January 1996, and then the country dismantled its Polynesian test sites. France signed the Comprehensive Nuclear-Test-Ban Treaty that same year, and then ratified the Treaty within two years.


title: Thermonuclear weapon

text: France confirmed that its nuclear arsenal contains about 300 warheads, carried by submarine-launched ballistic missiles (SLBMs) and fighter-bombers in 2015. France has four Triomphant-class ballistic missile submarines. One ballistic missile submarine is deployed in the deep ocean, but a total of three must be in operational use at all times. The three older submarines are armed with 16 M45 missiles. The newest submarine, "Le Terrible", was commissioned in 2010, and it has M51 missiles capable of carrying TN 75 thermonuclear warheads. The air fleet is four squadrons at four different bases. In total, there are 23 Mirage 2000N aircraft and 20 Rafales capable of carrying nuclear warheads. The M51.1 missiles are intended to be replaced with the new M51.2 warhead beginning in 2016, which has a greater range than the M51.1.


title: Thermonuclear weapon

text: France also has about 60 air-launched missiles tipped with TN 80/TN 81 warheads with a yield of about each. France's nuclear program has been carefully designed to ensure that these weapons remain usable decades into the future. Currently, France is no longer deliberately producing critical mass materials such as plutonium and enriched uranium, but it still relies on nuclear energy for electricity, with as a byproduct.


title: Thermonuclear weapon

text: On 11 May 1998, India announced that it had detonated a thermonuclear bomb in its Operation Shakti tests ("Shakti-I", specifically, in Hindi the word 'Shakti' means power). Dr. Samar Mubarakmand, a Pakistani nuclear physicist, asserted that if Shakti-I had been a thermonuclear test, the device had failed to fire. However, Dr. Harold M. Agnew, former director of the Los Alamos National Laboratory, said that India's assertion of having detonated a staged thermonuclear bomb was believable. India says that their thermonuclear device was tested at a controlled yield of because of the close proximity of the Khetolai village at about , to ensure that the houses in that village do not suffer significant damage. Another cited reason was that radioactivity released from yields significantly more than 45 Kilotons might not have been contained fully. After the Pokhran-II tests, Dr. Rajagopal Chidambaram, former chairman of the Atomic Energy Commission of India said that India has the capability to build thermonuclear bombs of any yield at will.


title: Thermonuclear weapon

text: The yield of India's hydrogen bomb test remains highly debatable among the Indian science community and the international scholars. The question of politicisation and disputes between Indian scientists further complicated the matter.


title: Thermonuclear weapon

text: In an interview in August 2009, the director for the 1998 test site preparations, Dr. K. Santhanam claimed that the yield of the thermonuclear explosion was lower than expected and that India should therefore not rush into signing the CTBT. Other Indian scientists involved in the test have disputed Dr. K. Santhanam's claim, arguing that Santhanam's claims are unscientific. British seismologist Roger Clarke argued that the magnitudes suggested a combined yield of up to , consistent with the Indian announced total yield of . U.S. seismologist Jack Evernden has argued that for correct estimation of yields, one should ‘account properly for geological and seismological differences between test sites’.


title: Thermonuclear weapon

text: India officially maintains that it can build thermonuclear weapons of various yields up to around on the basis of the Shakti-1 thermonuclear test.


title: Thermonuclear weapon

text: Israel is alleged to possess thermonuclear weapons of the Teller–Ulam design, but it is not known to have tested any nuclear devices, although it is widely speculated that the Vela incident of 1979 may have been a joint Israeli–South African nuclear test.


title: Thermonuclear weapon

text: It is well established that Edward Teller advised and guided the Israeli establishment on general nuclear matters for some twenty years. Between 1964 and 1967, Teller made six visits to Israel where he lectured at the Tel Aviv University on general topics in theoretical physics. It took him a year to convince the CIA about Israel's capability and finally in 1976, Carl Duckett of the CIA testified to the U.S. Congress, after receiving credible information from an "American scientist" (Teller), on Israel's nuclear capability. During the 1990s, Teller eventually confirmed speculations in the media that it was during his visits in the 1960s that he concluded that Israel was in possession of nuclear weapons. After he conveyed the matter to the higher level of the U.S. government, Teller reportedly said: "They [Israel] have it, and they were clever enough to trust their research and not to test, they know that to test would get them into trouble."


title: Thermonuclear weapon

text: According to the scientific data received and published by PAEC, the Corps of Engineers, and Kahuta Research Laboratories (KRL), in May 1998, Pakistan carried out six underground nuclear tests in Chagai Hills and Kharan Desert in Balochistan Province (see the code-names of the tests, "Chagai-I" and "Chagai-II"). None of these boosted fission devices was the thermonuclear weapon design, according to KRL and PAEC.


title: Thermonuclear weapon

text: North Korea claimed to have tested its miniaturised thermonuclear bomb on 6 January 2016. North Korea's first three nuclear tests (2006, 2009 and 2013) were relatively low yield and do not appear to have been of a thermonuclear weapon design. In 2013, the South Korean Defense Ministry speculated that North Korea may be trying to develop a "hydrogen bomb" and such a device may be North Korea's next weapons test. In January 2016, North Korea claimed to have successfully tested a hydrogen bomb, although only a magnitude 5.1 seismic event was detected at the time of the test, a similar magnitude to the 2013 test of a atomic bomb. These seismic recordings cast doubt upon North Korea's claim that a hydrogen bomb was tested and suggest it was a non-fusion nuclear test.


title: Thermonuclear weapon

text: On 3 September 2017, the country's state media reported that a hydrogen bomb test was conducted which resulted in "perfect success". According to the U.S. Geological Survey (USGS), the blast resulted in an earthquake with a magnitude of 6.3, 10 times more powerful than previous nuclear tests conducted by North Korea. U.S. Intelligence released an early assessment that the yield estimate was , with an uncertainty range of .


title: Thermonuclear weapon

text: On 12 September, NORSAR revised its estimate of the earthquake magnitude upward to 6.1, matching that of the CTBTO, but less powerful than the USGS estimate of 6.3. Its yield estimate was revised to , while noting the estimate had some uncertainty and an undisclosed margin of error.


title: Thermonuclear weapon

text: On 13 September, an analysis of before and after synthetic-aperture radar satellite imagery of the test site was published suggesting the test occurred under of rock and the yield "could have been in excess of 300 kilotons".


title: Thermonuclear weapon

text: The Teller–Ulam design was for many years considered one of the top nuclear secrets, and even today it is not discussed in any detail by official publications with origins "behind the fence" of classification. United States Department of Energy (DOE) policy has been, and continues to be, that they do not acknowledge when "leaks" occur, because doing so would acknowledge the accuracy of the supposed leaked information. Aside from images of the warhead casing, most information in the public domain about this design is relegated to a few terse statements by the DOE and the work of a few individual investigators.


title: Thermonuclear weapon

text: In 1972 the United States government declassified a document stating "[I]n thermonuclear (TN) weapons, a fission 'primary' is used to trigger a TN reaction in thermonuclear fuel referred to as a 'secondary'", and in 1979 added, "[I]n thermonuclear weapons, radiation from a fission explosive can be contained and used to transfer energy to compress and ignite a physically separate component containing thermonuclear fuel." To this latter sentence the US government specified that ""Any elaboration of this statement will be classified"." The only information that may pertain to the "spark plug" was declassified in 1991: "Fact that fissile or fissionable materials are present in some secondaries, material unidentified, location unspecified, use unspecified, and weapons undesignated." In 1998 the DOE declassified the statement that "The fact that materials may be present in channels and the term 'channel filler,' with no elaboration", which may refer to the polystyrene foam (or an analogous substance).


title: Thermonuclear weapon

text: Whether these statements vindicate some or all of the models presented above is up for interpretation, and official U.S. government releases about the technical details of nuclear weapons have been purposely equivocating in the past (see, e.g., Smyth Report). Other information, such as the types of fuel used in some of the early weapons, has been declassified, though precise technical information has not been.


title: Thermonuclear weapon

text: Most of the current ideas on the workings of the Teller–Ulam design came into public awareness after the Department of Energy (DOE) attempted to censor a magazine article by U.S. antiweapons activist Howard Morland in 1979 on the "secret of the hydrogen bomb". In 1978, Morland had decided that discovering and exposing this "last remaining secret" would focus attention onto the arms race and allow citizens to feel empowered to question official statements on the importance of nuclear weapons and nuclear secrecy. Most of Morland's ideas about how the weapon worked were compiled from highly accessible sources—the drawings that most inspired his approach came from none other than the "Encyclopedia Americana". Morland also interviewed (often informally) many former Los Alamos scientists (including Teller and Ulam, though neither gave him any useful information), and used a variety of interpersonal strategies to encourage informative responses from them (i.e., asking questions such as "Do they still use spark plugs?" even if he was not aware what the latter term specifically referred to).


title: Thermonuclear weapon

text: Morland eventually concluded that the "secret" was that the "primary" and "secondary" were kept separate and that radiation pressure from the "primary" compressed the "secondary" before igniting it. When an early draft of the article, to be published in "The Progressive" magazine, was sent to the DOE after falling into the hands of a professor who was opposed to Morland's goal, the DOE requested that the article not be published, and pressed for a temporary injunction. The DOE argued that Morland's information was (1) likely derived from classified sources, (2) if not derived from classified sources, itself counted as "secret" information under the "born secret" clause of the 1954 Atomic Energy Act, and (3) was dangerous and would encourage nuclear proliferation.


title: Thermonuclear weapon

text: Morland and his lawyers disagreed on all points, but the injunction was granted, as the judge in the case felt that it was safer to grant the injunction and allow Morland, et al., to appeal, which they did in "United States v. The Progressive" (1979).


title: Thermonuclear weapon

text: Through a variety of more complicated circumstances, the DOE case began to wane as it became clear that some of the data they were attempting to claim as "secret" had been published in a students' encyclopedia a few years earlier. After another H-bomb speculator, Chuck Hansen, had his own ideas about the "secret" (quite different from Morland's) published in a Wisconsin newspaper, the DOE claimed that "The Progressive" case was moot, dropped its suit, and allowed the magazine to publish its article, which it did in November 1979. Morland had by then, however, changed his opinion of how the bomb worked, suggesting that a foam medium (the polystyrene) rather than radiation pressure was used to compress the "secondary", and that in the "secondary" there was a "spark plug" of fissile material as well. He published these changes, based in part on the proceedings of the appeals trial, as a short erratum in "The Progressive" a month later. In 1981, Morland published a book about his experience, describing in detail the train of thought that led him to his conclusions about the "secret".


title: Thermonuclear weapon

text: Morland's work is interpreted as being at least partially correct because the DOE had sought to censor it, one of the few times they violated their usual approach of not acknowledging "secret" material that had been released; however, to what degree it lacks information, or has incorrect information, is not known with any confidence. The difficulty that a number of nations had in developing the Teller–Ulam design (even when they apparently understood the design, such as with the United Kingdom), makes it somewhat unlikely that this simple information alone is what provides the ability to manufacture thermonuclear weapons. Nevertheless, the ideas put forward by Morland in 1979 have been the basis for all the current speculation on the Teller–Ulam design.


title: Thermonuclear weapon

text: In January 1986, Soviet leader Mikhail Gorbachev publicly proposed a three-stage program for abolishing the world's nuclear weapons by the end of the 20th century. Two years before his death in 1989, Andrei Sakharov's comments at a scientists’ forum helped begin the process for the elimination of thousands of nuclear ballistic missiles from the US and Soviet arsenals. Sakharov (1921–89) was recruited into the Soviet Union's nuclear weapons program in 1948, a year after he completed his doctorate. In 1949 the US detected the first Soviet test of a fission bomb, and the two countries embarked on a desperate race to design a thermonuclear hydrogen bomb that was a thousand times more powerful. Like his US counterparts, Sakharov justified his H-bomb work by pointing to the danger of the other country's achieving a monopoly. But also like some of the US scientists who had worked on the Manhattan Project, he felt a responsibility to inform his nation's leadership and then the world about the dangers from nuclear weapons. Sakharov's first attempt to influence policy was brought about by his concern about possible genetic damage from long-lived radioactive carbon-14 created in the atmosphere from nitrogen-14 by the enormous fluxes of neutrons released in H-bomb tests. In 1968, a friend suggested that Sakharov write an essay about the role of the intelligentsia in world affairs. Self-publishing was the method at the time for spreading unapproved manuscripts in the Soviet Union. Many readers would create multiple copies by typing with multiple sheets of paper interleaved with carbon paper. One copy of Sakharov's essay, "Reflections on Progress, Peaceful Coexistence, and Intellectual Freedom", was smuggled out of the Soviet Union and published by the New York Times. More than 18 million reprints were produced during 1968–69. After the essay was published, Sakharov was barred from returning to work in the nuclear weapons program and took a research position in Moscow. In 1980, after an interview with the New York Times in which he denounced the Soviet invasion of Afghanistan, the government put him beyond the reach of Western media by exiling him and his wife to Gorky. In March 1985, Gorbachev became general secretary of the Soviet Communist Party. More than a year and a half later, he persuaded the Politburo, the party's executive committee, to allow Sakharov and Bonner to return to Moscow. Sakharov was elected as an opposition member to the Soviet Congress of People's Deputies in 1989. Later that year he had a cardiac arrhythmia and died in his apartment. He left behind a draft of a new Soviet constitution that emphasized democracy and human rights.


title: Thermonuclear weapon

text: On 5 February 1958, during a training mission flown by a B-47, a Mark 15 nuclear bomb, also known as the Tybee Bomb, was lost off the coast of Tybee Island near Savannah, Georgia. The bomb was thought by the Department of Energy to lie buried under several feet of silt at the bottom of Wassaw Sound.


title: Thermonuclear weapon

text: On 17 January 1966, a fatal collision occurred between a B-52G and a KC-135 Stratotanker over Palomares, Spain. The conventional explosives in two of the Mk28-type hydrogen bombs detonated upon impact with the ground, dispersing plutonium over nearby farms. A third bomb landed intact near Palomares while the fourth fell 12 miles (19 km) off the coast into the Mediterranean sea.


title: Thermonuclear weapon

text: On 21 January 1968, a B-52G, with four B28FI thermonuclear bombs aboard as part of Operation Chrome Dome, crashed on the ice of the North Star Bay while attempting an emergency landing at Thule Air Base in Greenland. The resulting fire caused extensive radioactive contamination. Personnel involved in the cleanup failed to recover all the debris from three of the bombs, and one bomb was not recovered.