From Wikipedia, the free encyclopedia
  (Redirected from Lightening)
Jump to: navigation, search
Not to be confused with Lighting.
For other uses, see Lightning (disambiguation).
"Return stroke" redirects here. For other uses, see Return stroke (disambiguation).
A lightning flash during a thunderstorm
Sound of a thunderstorm
High-speed, slow-motion lightning video captured at 6,200 frames per second.


General considerations[edit]

On Earth, the lightning frequency is approximately 40–50 times a second or nearly 1.4 billion flashes per year[1] and the average duration is 30 microseconds.[2] Many factors affect the frequency, distribution, strength and physical properties of a "typical" lightning flash in a particular region of the world. These factors include ground elevation, latitude, prevailing wind currents, relative humidity, proximity to warm and cold bodies of water, etc. To a certain degree, the ratio between IC, CC and CG lightning may also vary by season in middle latitudes. Because human beings are terrestrial and most of their possessions are on the Earth, where lightning can damage or destroy them, CG lightning is the most studied and best understood of the three types, even though IC and CC are more common types of lightning. Lightning's relative unpredictability limits a complete explanation of how or why it occurs, even after hundreds of years of scientific investigation.

A typical cloud to ground lightning flash culminates in the formation of an electrically conducting plasma channel through the air in excess of 5 kilometres (3.1 mi) tall, from within the cloud to the ground's surface. The actual discharge is the final stage of a very complex process.[3] At its peak, a typical thunderstorm produces three or more strikes to the Earth per minute.[4] Lightning primarily occurs when warm air is mixed with colder air masses, resulting in atmospheric disturbances necessary for polarizing the atmosphere.[citation needed] However, it can also occur during dust storms, forest fires, tornadoes, volcanic eruptions, and even in the cold of winter, where the lightning is known as thundersnow.[5][6] Hurricanes typically generate some lightning, mainly in the rainbands as much as 160 kilometres (99 mi) from the center.[7][8][9]


General properties[edit]


Lightning is not distributed evenly around the planet, as seen in the image on the right.



Lightning in Belfort, France



On Earth, the place where lightning occurs most often is near the small village of Kifuka in the mountains of the eastern Democratic Republic of the Congo,[12] where the elevation is around 975 m (3,200 ft). On average, this region receives 158 lightning strikes per 1 square kilometer (0.39 sq mi) per year.[13] Other lightning hotspots include Catatumbo in Venezuela, Singapore,[14] Teresina in northern Brazil,[15] and "Lightning Alley" in Central Florida (in the USA).[16][17]

Establishing conditions necessary for lightning[edit]

In order for an electrostatic discharge to occur, two things are necessary: 1) a sufficiently high electric potential between two regions of space must exist; and 2) a high-resistance medium must obstruct the free, unimpeded equalization of the opposite charges.

  1. It is well understood that during a thunderstorm there is charge separation and aggregation in certain regions of the cloud; however the exact processes by which this occurs are not fully understood;[18]
    Main article: thunderstorm
  2. The atmosphere provides the electrical insulation, or barrier, that prevents free equalization between charged regions of opposite polarity. This is overcome by "lightning", a complex process referred to as the lightning "flash".

Establishing the electric field in CG lightning

View of lightning from an airplane flying above a system.

Lightning flashes and strikes[edit]


Downward leader formation for negative CG lightning[edit]

A downward leader travels towards earth, branching as it goes.

In a process not well understood, a channel of ionized air, called a "leader", is initiated from a charged region in the thundercloud. Leaders are electrically conductive channels of partially ionized gas that travel away from a region of dense charge. Negative leaders propagate away from densely charged regions of negative charge, and positive leaders propagate from positively charged regions.


Leaders often split, forming branches in a tree-like pattern.[19] In addition, negative leaders travel in a discontinuous fashion. The resulting jerky movement of these "stepped leader(s)" can be readily observed in slow-motion videos of negative leaders as they head toward ground prior to a negative CG lightning strike. The negative leaders continue to propagate and split as they head downward, often speeding up as they get closer to the Earth's surface.

About 90% of ionic channel lengths between "pools" are approximately 45 m (148 ft) in length.[20] The establishment of the ionic channel takes a comparatively long amount of time (hundreds of milliseconds) in comparison to resulting discharge which occurs within a few microseconds. The electric current needed to establish the channel, measured in the tens or hundreds of amperes, is dwarfed by subsequent currents during the actual discharge.

Initiation of the outward leaders is not well understood. The electric field strength within the thundercloud is not typically large enough to initiate this process by itself.[21] Many hypotheses have been proposed. One theory postulates that showers of relativistic electrons are created by cosmic rays and are then accelerated to higher velocities via a process called runaway breakdown. As these relativistic electrons collide and ionize neutral air molecules, they initiate leader formation. Another theory invokes locally enhanced electric fields being formed near elongated water droplets or ice crystals.[22] Percolation theory, especially for the case of biased percolation,[23] [clarification needed] describes random connectivity phenomena, which produce an evolution of connected structures similar to that of lightning strikes.

Upward streamers[edit]




Once a downward leader connects to an available upward leader, a process referred to as attachment, a low-resistance path is formed and discharge may occur. Photographs have been taken on which unattached streamers are clearly visible. The unattached downward leaders are also visible in branched lightning, none of which are connected to the earth, although it may appear they are.[26]


Return stroke[edit]

Once a conductive channel bridges the ionized air between the negative charges in the cloud and the positive surface charges below, a massive electrical discharge follows. Neutralization of positive surface charges occurs first. An enormous current of positive charges races up the ionic channel towards the thundercloud. This is the 'return stroke' and it is the most luminous and noticeable part of the lightning discharge.


The positive charges in the ground region surrounding the lightning strike are neutralized within microseconds as they race inward to the strike point, up the plasma channel, and back to the cloud.[citation needed] A huge surge of current creates large radial voltage differences along the surface of the ground. Called step potentials, they are responsible for more injuries and deaths than the strike itself.[citation needed] Electricity follows the path of least resistance. A portion of the return stroke current will often preferentially flow through one leg and out another, electrocuting an unlucky human or animal standing near the point where the lightning strikes.

The electrical current of the return stroke averages 30 kiloamperes for a typical negative CG flash, often referred to as "negative CG" lightning. In some cases, a positive ground to cloud (GC) lightning flash may originate from a positively charged region on the ground below a storm. These discharges normally originate from the tops of very tall structures, such as communications antennas. The rate at which the return stroke current travels has been found to be around 1×108 m/s.[27]

The massive flow of electrical current occurring during the return stroke combined with the rate at which it occurs (measured in microseconds) rapidly superheats the completed leader channel, forming a highly electrically conductive plasma channel. The core temperature of the plasma during the return stroke may exceed 50,000 K, causing it to brilliantly radiate with a blue-white color. Once the electrical current stops flowing, the channel cools and dissipates over tens or hundreds of milliseconds, often disappearing as fragmented patches of glowing gas. The nearly instantaneous heating during the return stroke causes the air to explosively expand, producing a powerful shock wave that is heard as thunder.





Transient currents during the flash[edit]

The electrical current within a typical negative CG lightning discharge rises very quickly to its peak value in 1–10 microseconds, then decays more slowly over 50–200 microseconds. The transient nature of the current within a lightning flash results in several phenomena that need to be addressed in the effective protection of ground-based structures. Rapidly changing currents tend to travel on the surface of a conductor. This is called skin effect, unlike direct currents "flowing through" the entire conductor like water through a hose. Hence, conductors used in the protection of facilities tend to be multi-stranded small wires woven together, that increases the surface area inversely in proportion to cross-sectional area.

The rapidly changing currents also create electromagnetic pulses (EMPs) that radiate outward from the ionic channel. This is a characteristic of all electrical sparks. The radiated pulses rapidly weaken as their distance from the origin increases. However if they pass over conductive elements, for instance electrical wires, communication lines or metallic pipes, they may induce a current which travels outward to its termination. This is the "surge" that, more often than not, results in the destruction of delicate electronics, electrical appliances or electric motors. Devices known as surge protectors (SPD) or transient voltage surge suppressors (TVSS) attached in series with these conductors can detect the lightning flash's transient [irregular] current, and through an alteration of its physical properties, route the spike to an attached earthing ground, thereby protecting the equipment from damage.


There are three primary types of lightning, defined by what is at the "ends" of a flash channel. They are intracloud (IC), which occurs within a single thundercloud unit; cloud to cloud (CC), which starts and ends between two different "functional" thundercloud units; and cloud to ground (CG), that primarily originates in the thundercloud and terminates on an Earth surface, but may also occur in the reverse direction, that is ground to cloud. There are variations of each type, such as "positive" versus "negative" CG flashes, that have different physical characteristics common to each which can be measured. Different common names used to describe a particular lightning event may be attributed to the same or different events.

Cloud to ground (CG)[edit]

Cloud-to-ground is the best known and third most common type of lightning. It is the best understood of all forms because it allows for scientific study given it terminates on a physical object, namely the Earth, and lends itself to being measured by instruments. Of the three primary types of lightning, it poses the greatest threat to life and property since it terminates or "strikes" the Earth. Cloud-to-ground (CG) lightning is a lightning discharge between a thundercloud and the ground. It is usually negative in polarity and is usually initiated by a stepped leader moving down from the cloud.

  • Ground-to-cloud lightning is an artificially initiated, or triggered, category of CG flashes. Triggered lightning originates from tall, positively charged structures on the ground, such as towers on mountains that have been inductively charged by the negative cloud layer above.[31]
  • Positive and negative lightning
CG lightning can occur with both positive and negative polarity. The polarity is that of the charge in the region that originated the lightning leaders. An average bolt of negative lightning carries an electric current of 30,000 amperes (30 kA), and transfers 15 coulombs of electric charge and 500 megajoules of energy. Large bolts of lightning can carry up to 120 kA and 350 coulombs.[32]
Anvil-to-ground (Bolt from the blue) lightning strike.
Unlike the far more common "negative" lightning, positive lightning originates from the positively charged top of the clouds (generally anvil clouds) rather than the lower portion of the storm. Leaders form in the anvil of the cumulonimbus and may travel horizontally for several miles before veering towards the ground. A positive lightning bolt can strike anywhere within several miles of the anvil of the thunderstorm, often in areas experiencing clear or only slightly cloudy skies; they are also known as "bolts from the blue" for this reason. Positive lightning typically makes up less than 5% of all lightning strikes.[33]
Because of the much greater distance to ground, the positively charged region can develop considerably larger levels of charge and voltages than the negative charge regions in the lower part of the cloud. Positive lightning bolts are considerably hotter and longer than negative lightning. They can develop six to ten times the amount of charge and voltage of a negative bolt and the discharge current may last ten times longer.[34] A bolt of positive lightning may carry an electric current of 300 kA and the potential at the top of the cloud may exceed a billion volts — about 10 times that of negative lightning.[35] During a positive lightning strike, huge quantities of extremely low frequency (ELF) and very low frequency (VLF) radio waves are generated.[36]
As a result of their greater power, as well as lack of warning, positive lightning strikes are considerably more dangerous. At the present time, aircraft are not designed to withstand such strikes, since their existence was unknown at the time standards were set, and the dangers unappreciated until the destruction of a glider in 1999.[37] The standard in force at the time of the crash, Advisory Circular AC 20-53A, was replaced by Advisory Circular AC 20-53B in 2006,[38] however it is unclear whether adequate protection against positive lightning was incorporated.[39][40]
Aircraft operating in U.S. airspace have been required to be equipped with static discharge wicks. Although their primary function is to mitigate radio interference due to static buildup through friction with the air, in the event of a lightning strike, a plane is designed to conduct the excess electricity through its skin and structure to the wicks to be safely discharged back into the atmosphere. These measures, however, may be insufficient for positive lightning.[41]
Positive lightning has also been shown to trigger the occurrence of Upper-atmospheric lightning between the tops of clouds and the ionosphere. Positive lightning tends to occur more frequently in winter storms, as with thundersnow, and in the dissipation stage of a thunderstorm.[42]

Cloud to cloud (CC) and Intra-Cloud (IC)[edit]

Branching of cloud to cloud lightning, New Delhi, India
Cloud-to-cloud lightning, Victoria, Australia.
Cloud-to-cloud lightning seen in Gresham, Oregon.





due to the habit of the charge typically originating from beneath or within the anvil and scrambling through the upper cloud layers of a thunderstorm, normally generating multiple branch strokes which are dramatic to witness. These are usually seen as a thunderstorm passes over the observer or begins to decay. The most vivid crawler behavior occurs in well developed thunderstorms that feature extensive rear anvil shearing.

Observational variations[edit]

  • Ball lightning may be an atmospheric electrical phenomenon, the physical nature of which is still controversial. The term refers to reports of luminous, usually spherical objects which vary from pea-sized to several meters in diameter.[43] It is sometimes associated with thunderstorms, but unlike lightning flashes, which last only a fraction of a second, ball lightning reportedly lasts many seconds. Ball lightning has been described by eyewitnesses but rarely recorded by meteorologists.[44][45] Scientific data on natural ball lightning is scarce owing to its infrequency and unpredictability. The presumption of its existence is based on reported public sightings, and has therefore produced somewhat inconsistent findings.
  • Smooth Channel lightning are positive cloud to ground lightning strikes where the forward stroke originates from the ground upwards to the cloud. The smooth channel is in the lower section of the lightning channel but should branch higher up (not visible as the "branching" is inside the cloud).[citation needed] Large supercells generate tremendous areas of positively charged cloud material (thick anvil) and wind shear prevents excessive negative strokes as with "normal" thunderstorms. Downdrafts, such as the forward flank downdraft (FFD), bring the positively charged cloud material closer to the ground, where such lightning occurs.[citation needed]
    This CG was of very short duration, exhibited highly branched channels and was very bright indicating that it was staccoto lightning near New Boston, Texas.
  • Superbolts are bolts of lightning around a hundred times brighter than normal. On Earth, one in a million lightning strikes is a superbolt.[citation needed]


Lightning strike[edit]

Main article: Lightning strike

Objects struck by lightning experience heat and magnetic forces of great magnitude. The heat created by lightning currents traveling through a tree may vaporize its sap, causing a steam explosion that bursts the trunk. As lightning travels through sandy soil, the soil surrounding the plasma channel may melt, forming tubular structures called fulgurites. Even though roughly 90 percent of people struck by lightning survive,[52] humans or animals struck by lightning may suffer severe injury due to internal organ and nervous system damage. Buildings or tall structures hit by lightning may be damaged as the lightning seeks unintended paths to ground. By safely conducting a lightning strike to ground, a lightning protection system can greatly reduce the probability of severe property damage. Lightning also oxidizes nitrogen in the air into nitrates which are deposited by rain and can fertilize plant growth.[53][54]


Main article: Thunder


Light travels at about 300,000,000 m/s. Sound travels through air at about 340 m/s. An observer can approximate the distance to the strike by timing the interval between the visible lightning and the audible thunder it generates. A lightning flash preceding its thunder by five seconds would be about one mile (1.6 km) (5x340 m) distant. A flash preceding thunder by three seconds is about one kilometer (0.62 mi) (3x340 m) distant. Consequently, a lightning strike observed at a very close distance will be accompanied by a sudden clap of thunder, with almost no perceptible time lapse, possibly accompanied by the smell of ozone (O3).

High-energy radiation[edit]

The production of X-rays by a bolt of lightning was theoretically predicted as early as 1925[55] but no evidence was found until 2001/2002,[56][57][58] when researchers at the New Mexico Institute of Mining and Technology detected X-ray emissions from an induced lightning strike along a grounded wire trailed behind a rocket shot into a storm cloud. In the same year University of Florida and Florida Tech researchers used an array of electric field and X-ray detectors at a lightning research facility in North Florida to confirm that natural lightning makes X-rays in large quantities during the propagation of stepped leaders. The cause of the X-ray emissions is still a matter for research, as the temperature of lightning is too low to account for the X-rays observed.[59][60]



Volcanic material thrust high into the atmosphere can trigger lightning.

Volcanic activity produces lightning-friendly conditions in multiple ways. The enormous quantity of pulverized material and gases ejected into the atmosphere with explosive power, creates a dense plume of highly charged particles, which establishes the perfect conditions for lightning. The ash density and constant motion within the volcanic plume continually produces electrostatic ionization, resulting in very powerful and very frequent flashes attempting to neutralize itself. Due to the extensive solid material (ash) content, unlike the water rich charge generating zones of a normal thundercloud, it is often called a dirty thunderstorm.


Extraterrestrial lightning[edit]

Lightning has been observed within the atmospheres of other planets, such as Venus, Jupiter and Saturn. Although in the minority on Earth, superbolts appear to be common on Jupiter.

Lightning on Venus has been a controversial subject after decades of study. During the Soviet Venera and U.S. Pioneer missions of the 1970s and 1980s, signals suggesting lightning may be present in the upper atmosphere were detected.[64] Although the Cassini–Huygens mission fly-by of Venus in 1999 detected no signs of lightning, the observation window lasted mere hours. Radio pulses recorded by the spacecraft Venus Express (which began orbiting Venus in April 2006) have been confirmed as originating from lightning on Venus.

Human related[edit]


Scientific study[edit]



When the local electric field exceeds the dielectric strength of damp air (about 3 million volts per meter), electrical discharge results in a strike, often followed by commensurate discharges branching from the same path. (See image, right.) Mechanisms that cause the charges to build up to lightning are still a matter of scientific investigation.[68][69] Lightning may be caused by the circulation of warm moisture-filled air through electric fields.[70] Ice or water particles then accumulate charge as in a Van de Graaff generator.[71]


Detection and monitoring[edit]

Ray counter in a museum.
Main article: Lightning detection

The earliest detector invented to warn of the approach of a thunder storm was the lightning bell. Benjamin Franklin installed one such device in his house.[73] [74] The detector was based on an electrostatic device called the 'electric chimes' invented by Andrew Gordon in 1742.


The Earth-ionosphere waveguide traps electromagnetic VLF- and ELF waves. Electromagnetic pulses transmitted by lightning strikes propagate within that waveguide. The waveguide is dispersive, which means that their group velocity depends on frequency. The difference of the group time delay of a lightning pulse at adjacent frequencies is proportional to the distance between transmitter and receiver. Together with direction finding methods, this allows to locate lightning strikes up to distances of 10000 km from their origin. Moreover, the eigenfrequencies of the Earth-ionospheric waveguide, the Schumann resonances at about 7.5 Hz, are used to determine the global thunderstorm activity.[77]


Artificially triggered[edit]

  • Laser-triggered
Since the 1970s,[82][83][84][85][86][87] researchers have attempted to trigger lightning strikes by means of infrared or ultraviolet lasers, which create a channel of ionized gas through which the lightning would be conducted to ground. Such triggering of lightning is intended to protect rocket launching pads, electric power facilities, and other sensitive targets.[88][89][90][91][92]

Physical manifestations[edit]


Lightning-induced magnetism[edit]

The movement of electrical charges produces a magnetic field (see electromagnetism). The intense currents of a lightning discharge create a fleeting but very strong magnetic field. Where the lightning current path passes through rock, soil, or metal these materials can become permanently magnetized. This effect is known as lightning-induced remanent magnetism, or LIRM. These currents follow the least resistive path, often horizontally near the surface[95][96] but sometimes vertically, where faults, ore bodies, or ground water offers a less resistive path.[97] One theory suggests that lodestones, natural magnets encountered in ancient times, were created in this manner.[98]

Lightning-induced magnetic anomalies can be mapped in the ground,[99][100] and analysis of magnetized materials can confirm lightning was the source of the magnetization[101] and provide an estimate of the peak current of the lightning discharge.[102]

Solar wind and cosmic rays[edit]

Some high energy cosmic rays produced by supernovas as well as solar particles from the solar wind, enter the atmosphere and electrify the air, creating pathways for lightning bolts.[103]

In culture[edit]

Further information: Lightning in religion






The lightning bolt is used to represent the instantaneous communication capabilities of electrically powered telegraphs and radios. It was a commonly used motif in Art Deco design, especially the zig-zag Art Deco design of the late 1920s.[109] The lightning bolt is a common insignia for military communications units throughout the world. A lightning bolt is also the NATO symbol for a signal asset.

See also[edit]



  2. ^ Hooft, Gerard; Vandoren, Stefan (2014). Time in Powers of Ten: Natural Phenomena and Their Timescales. World Scientific. ISBN 978-981-4489-81-2. 
  3. ^ Uman (1986) p. 81.
  4. ^ Uman (1986) p. 55.
  5. ^ New Lightning Type Found Over Volcano?. (February 2010). Retrieved on June 23, 2012.
  6. ^ "Bench collapse sparks lightning, roiling clouds". Volcano Watch. United States Geological Society. June 11, 1998. Retrieved October 7, 2012. 
  7. ^ Pardo-Rodriguez, Lumari (Summer 2009) Lightning Activity in Atlantic Tropical Cyclones: Using the Long-Range Lightning Detection Network (LLDN). MA Climate and Society, Columbia University Significant Opportunities in Atmospheric Research and Science Program.
  8. ^ Hurricane Lightning, NASA, January 9, 2006.
  9. ^ The Promise of Long-Range Lightning Detection in Better Understanding, Nowcasting, and Forecasting of Maritime Storms. Long Range Lightning Detection Network
  10. ^ "Where LightningStrikes". NASA Science. Science News. December 5, 2001. Retrieved July 5, 2010. 
  11. ^ Uman (1986) Ch. 8, p. 68.
  12. ^ "Kifuka – place where lightning strikes most often". Wondermondo. Retrieved November 21, 2010. 
  14. ^ "Lightning Activity in Singapore". National Environmental Agency. 2002. Archived from the original on 2007-09-27. Retrieved September 24, 2007. 
  15. ^ "Teresina: Vacations and Tourism". Paesi Online. Archived from the original on September 5, 2008. Retrieved September 24, 2007. 
  16. ^ "Staying Safe in Lightning Alley". NASA. January 3, 2007. Retrieved September 24, 2007. 
  17. ^ Pierce, Kevin (2000). "Summer Lightning Ahead". Florida Retrieved September 24, 2007. 
  18. ^ Saunders, C. P. R. (1993). "A Review of Thunderstorm Electrification Processes". Journal of Applied Meteorology 32 (4): 642. Bibcode:1993JApMe..32..642S. doi:10.1175/1520-0450(1993)032<0642:AROTEP>2.0.CO;2. 
  19. ^ Ultraslow-motion video of stepped leader propagation:
  21. ^ Stolzenburg, Maribeth; Marshall, Thomas C. (2008). "Charge Structure and Dynamics in Thunderstorms". Space Science Reviews 137: 355. Bibcode:2008SSRv..137..355S. doi:10.1007/s11214-008-9338-z. 
  22. ^ Petersen, Danyal; Bailey, Matthew; Beasley, William H.; Hallett, John (2008). "A brief review of the problem of lightning initiation and a hypothesis of initial lightning leader formation". Journal of Geophysical Research 113. Bibcode:2008JGRD..11317205P. doi:10.1029/2007JD009036. 
  23. ^ Hooyberghs, Hans; Van Schaeybroeck, Bert; Moreira, André A.; Andrade, José S.; Herrmann, Hans J.; Indekeu, Joseph O. (2010). "Biased percolation on scale-free networks". Physical Review E 81. arXiv:0908.3786. Bibcode:2010PhRvE..81a1102H. doi:10.1103/PhysRevE.81.011102. 
  26. ^ File:Lightning hits tree.jpg
  27. ^ Idone, V. P.; Orville, R. E.; Mach, D. M.; Rust, W. D. (1987). "The propagation speed of a positive lightning return stroke". Geophysical Research Letters 14 (11): 1150. Bibcode:1987GeoRL..14.1150I. doi:10.1029/GL014i011p01150.  edit
  28. ^ Uman (1986) Ch. 5, p. 41.
  29. ^ Uman (1986) pp. 103–110.
  30. ^ Uman (1986) Ch. 9, p. 78.
  31. ^ "Questions and Answers about Lightning: Basics". Lightning Basics. National Severe Storms Laboratory. Retrieved September 28, 2012. 
  32. ^ Hasbrouck, Richard. Mitigating Lightning Hazards, Science & Technology Review May 1996. Retrieved on April 26, 2009.
  33. ^ "NWS JetStream – The Positive and Negative Side of Lightning". National Oceanic and Atmospheric Administration. Retrieved September 25, 2007. 
  35. ^ The Positive and Negative Side of Lightning, National Weather Service JetStream January 2010. Retrieved on June 11, 2011.
  37. ^ "Air Accidents Investigation Branch (AAIB) Bulletins 1999 December: Schleicher ASK 21 two seat glider". Retrieved May 17, 2015. 
  38. ^ FAA Advisory Circulars. Retrieved on June 23, 2012.
  40. ^ A Proposed Addition to the Lightning Environment Standards Applicable to Aircraft, J. Anderson Plumer Lightning Technologies, Inc, published September 27, 2005
  41. ^ Ask Us – Static Discharge Wicks. (June 26, 2005). Retrieved on June 23, 2012.
  42. ^ a b Christian, Hugh J. and McCook, Melanie A. "A Lightning Primer – Characteristics of a Storm". NASA. Retrieved February 8, 2009. 
  44. ^ Ball, Philip (January 17, 2014). "Focus:First Spectrum of Ball Lightning". Focus. American Physical Society. Retrieved January 18, 2014. 
  45. ^ Tennakone, Kirthi (2007). "Ball Lightning". Georgia State University. Retrieved September 21, 2007. 
  46. ^ Robinson, Dan. "Weather Library: Lightning Types & Classifications". Retrieved March 17, 2013. 
  47. ^ Scott, A (2000). "The Pre-Quaternary history of fire". Palaeogeography Palaeoclimatology Palaeoecology 164 (1–4): 281. doi:10.1016/S0031-0182(00)00192-9. 
  48. ^ Haby, Jeff. "What is heat lightning?". 
  49. ^ "Definition of Rocket Lightning, AMS Glossary of Meteorology". Retrieved July 5, 2007. 
  50. ^ "Glossary". National Oceanic and Atmospheric Administration. National Weather Service. Retrieved September 2, 2008. 
  52. ^ Jabr, Ferris (22 September 2014). "Lightning-Strike Survivors Tell Their Stories". Outside. Retrieved 28 September 2014. 
  53. ^ Bond, D.W., Steiger, S., Zhang, R., Tie, X., Orville, R.E. 2002. The importance of NOx production by lightning in the tropics. Atmospheric Environment 36:1509–1519.
  55. ^ Wilson, C.T.R. (1925). "The acceleration of beta-particles in strong electric fields such as those of thunderclouds". Proceedings of the Cambridge Philosophical Society 22 (4): 534–538. Bibcode:1925PCPS...22..534W. doi:10.1017/S0305004100003236. 
  56. ^ Moore, C. B.; Eack, K. B.; Aulich, G. D.; Rison, W. (2001). "Energetic radiation associated with lightning stepped-leaders". Geophysical Research Letters 28 (11): 2141. Bibcode:2001GeoRL..28.2141M. doi:10.1029/2001GL013140.  edit
  57. ^ Dwyer, J. R.; Uman, M. A.; Rassoul, H. K.; Al-Dayeh, M.; Caraway, L.; Jerauld, J.; Rakov, V. A.; Jordan, D. M.; Rambo, K. J.; Corbin, V.; Wright, B. (2003). "Energetic Radiation Produced During Rocket-Triggered Lightning" (PDF). Science 299 (5607): 694–697. doi:10.1126/science.1078940. PMID 12560549.  edit
  58. ^ Newitz, A. (September 2007) "Educated Destruction 101," Popular Science, p. 61.
  59. ^ Scientists close in on source of X-rays in lightning,, July 15, 2008. Retrieved July 2008.
  60. ^ Prostak, Sergio (April 11, 2013). "Scientists Explain Invisible ‘Dark Lightning'". Retrieved July 9, 2013. 
  61. ^ Signature Of Antimatter Detected In Lightning – Science News. (December 5, 2009). Retrieved on June 23, 2012.
  63. ^ Dell'Amore, Christine (February 3, 2010) New Lightning Type Found Over Volcano?. National Geographic News.
  64. ^ Strangeway, Robert J. (1995). "Plasma Wave Evidence for Lightning on Venus". Journal of Atmospheric and Terrestrial Physics 57 (5): 537–556. Bibcode:1995JATP...57..537S. doi:10.1016/0021-9169(94)00080-8. Retrieved September 24, 2007. 
  65. ^ Uman (1986) Ch. 4, pp. 26–34.
  67. ^ Uman (1986) pp. 103–110
  68. ^ Fink, Micah. "How Lightning Forms". Public Broadcasting System. Retrieved September 21, 2007. 
  69. ^ National Weather Service (2007). "Lightning Safety". National Weather Service. Retrieved September 21, 2007. 
  70. ^ Uman (1986) p. 61.
  71. ^ Rakov and Uman, p. 84.
  72. ^ Thomson, E. M.; Uman, M. A.; Beasley, W. H. (January 1985). "Speed and current for lightning stepped leaders near ground as determined from electric field records". Journal of Geophysical Research 90 (D5): 8136. Bibcode:1985JGR....90.8136T. doi:10.1029/JD090iD05p08136. 
  73. ^ The Franklin Institute. Ben Franklin's Lightning Bells. Retrieved December 14, 2008.
  74. ^ Video demonstration of how Franklin's Bell worked
  75. ^ "Lightning Detection Systems". Retrieved July 27, 2007.  NOAA page on how the U.S. national lightning detection system operates
  78. ^ "NASA Dataset Information". NASA. 2007. Retrieved September 11, 2007. 
  79. ^ "NASA LIS Images". NASA. 2007. Retrieved September 11, 2007. 
  80. ^ "NASA OTD Images". NASA. 2007. Retrieved September 11, 2007. 
  81. ^ Kridler, Chris (July 25, 2002). "Triggered lightning video" (VIDEO). requires QuickTime. Chris Kridler's Sky Diary. Retrieved September 24, 2007. 
  82. ^ Koopman, David W. & Wilkerson, T. D. (1971). "Channeling of an Ionizing Electrical Streamer by a Laser Beam". Journal of Applied Physics 42 (5): 1883–1886. Bibcode:1971JAP....42.1883K. doi:10.1063/1.1660462. 
  83. ^ Saum, K. A. & Koopman, David W. (November 1972). "Discharges Guided by Laser-Induced Rarefaction Channels". Physics of Fluids 15 (11): 2077–2079. Bibcode:1972PhFl...15.2077S. doi:10.1063/1.1693833. 
  84. ^ Schubert, C. W. (1977). "The laser lightning rod: A feasibility study". Technical report AFFDL-TR-78-60, ADA063847, [U.S.] Air Force Flight Dynamics Laboratory, Wright-Patterson AFB [Air Force Base] Ohio. 
  85. ^ Schubert, Charles W. & Lippert, Jack R. (1979). "Investigation into triggering lightning with a pulsed laser" (PDF). In Guenther, A. H. & Kristiansen, M. Proceedings of the 2nd IEEE International Pulse Power Conference, Lubbock, Texas, 1979. Piscataway, NJ: IEEE. pp. 132–135. 
  86. ^ Lippert, J. R. (1977). "A laser-induced lightning concept experiment". Final Report (Air Force Flight Dynamics Lab., Wright-Patterson AFB). Bibcode:1978affd.rept.....L. 
  87. ^ Rakov and Uman, pp. 296–299.
  88. ^ "UNM researchers use lasers to guide lightning". Campus News, The University of New Mexico. January 29, 2001. Archived from the original on 2012-07-09. Retrieved July 28, 2007. 
  89. ^ Khan, N.; Mariun, N.; Aris, I.; Yeak, J. (2002). "Laser-triggered lightning discharge". New Journal of Physics 4: 61. doi:10.1088/1367-2630/4/1/361.  edit
  90. ^ Rambo, P.; Biegert, J.; Kubecek, V.; Schwarz, J.; Bernstein, A.; Diels, J.-C.; Bernstein, R. & Stahlkopf, K. (1999). "Laboratory tests of laser-induced lightning discharge". Journal of Optical Technology 66 (3): 194–198. doi:10.1364/JOT.66.000194. 
  92. ^ Wang, D.; Ushio, T.; Kawasaki, Z. -I.; Matsuura, K.; Shimada, Y.; Uchida, S.; Yamanaka, C.; Izawa, Y.; Sonoi, Y.; Simokura, N. (1995). "A possible way to trigger lightning using a laser". Journal of Atmospheric and Terrestrial Physics 57 (5): 459. doi:10.1016/0021-9169(94)00073-W.  edit
  93. ^ "Terawatt Laser Beam Shot in the Clouds Provokes Lightning Strike".  News report based on: Kasparian, J.; Ackermann, R.; André, Y. B.; Méchain, G. G.; Méjean, G.; Prade, B.; Rohwetter, P.; Salmon, E.; Stelmaszczyk, K.; Yu, J.; Mysyrowicz, A.; Sauerbrey, R.; Woeste, L.; Wolf, J. P. (2008). "Electric events synchronized with laser filaments in thunderclouds". Optics Express 16 (8): 5757–63. doi:10.1364/OE.16.005757. PMID 18542684.  edit
  94. ^ "Laser Triggers Electrical Activity in Thunderstorm for the First Time". Newswise. Retrieved August 6, 2008.  News report based on Kasparian et al. Méjean, pp. 5757–5763
  95. ^ Graham, K.W.T. (1961). "The Re-magnetization of a Surface Outcrop by Lightning Currents". Geophysical Journal International 6: 85. Bibcode:1961GeoJI...6...85G. doi:10.1111/j.1365-246X.1961.tb02963.x. 
  96. ^ Cox A. (1961). Anomalous Remanent Magnetization of Basalt. U.S. Geological Survey Bulletin 1038-E, pp. 131–160.
  100. ^ Archaeo-Physics, LLC | Lightning-induced magnetic anomalies on archaeological sites. Retrieved on June 23, 2012.
  101. ^ Maki, David (2005). "Lightning strikes and prehistoric ovens: Determining the source of magnetic anomalies using techniques of environmental magnetism". Geoarchaeology: an International Journal 20 (5): 449–459. doi:10.1002/gea.20059. 
  102. ^ Verrier, V.; Rochette, P. (2002). "Estimating Peak Currents at Ground Lightning Impacts Using Remanent Magnetization". Geophysical Research Letters 29 (18): 1867. Bibcode:2002GeoRL..29r..14V. doi:10.1029/2002GL015207. 
  103. ^ "High-speed solar winds increase lightning strikes on Earth". 2014-05-15. Retrieved 2014-05-19. 
  104. ^ Lightning: Gods and Sciences
  105. ^ Uman (1986) Ch. 6, p. 47.
  106. ^ "Jesus actor struck by lightning". BBC News. October 23, 2003. Retrieved August 19, 2007. 
  107. ^ Picture of John Kaspar of the National States Rights Party speaking in front of the party’s lightning bolt flag (the flag was red, white, and blue). (November 6, 2010). Retrieved on April 9, 2013.
  108. ^ "Lightning". Phar Lap: Australia's wonder horse. Museum Victoria. 


Further reading[edit]

External links[edit]