Plasmas/Plasma objects/Astronomy

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This image shows the coronal cloud around and near to the Sun as viewed by the Soft X-Ray Telescope (SXT) onboard the orbiting Yohkoh satellite. Credit: NASA Goddard Laboratory for Atmospheres.



Main source: Plasmas


"Plasma is the fourth state of matter, consisting of electrons, ions and neutral atoms, usually at temperatures above 104 degrees Kelvin."[2] "The sun and stars are plasmas; the earth's ionosphere, Van Allen belts, magnetosphere, etc., are all plasmas. Indeed, plasma makes up much of the known matter in the universe."[2]

Plasma objects[edit]

Representation of upper-atmospheric lightning and electrical-discharge phenomena are displayed. Credit: .


Theoretical plasma astronomy[edit]

Because "of the huge spatiotemporal scales of plasma objects in space, the basic accepted views about the theory of plasma stability, which is now better suited for laboratory applications, are already in need of revision."[4]


Arcs rise above an active region on the surface of the Sun in this series of images taken by the STEREO (Behind) spacecraft. Credit: Images courtesy of the NASA STEREO Science Center.

Def. "[a] massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space"[5] is called a coronal mass ejection (CME).


This image of the Northern Lights shows the very rare blue light. Credit: Varjisakka.

"Blue starters were discovered on video from a night time research flight around thunderstorms [6] and appear to be "an upward moving luminous phenomenon closely related to blue jets."[7] They appear to be shorter and brighter than blue jets, reaching altitudes of only up to 20 km.[8]

"Blue starters appear to be blue jets that never quite make it".[9]

At left is an image of the Northern Lights on Earth showing the very rare blue lights.


2 kW Hall thruster is in operation as part of the Hall Thruster Experiment at the Princeton Plasma Physics Laboratory. Credit: Dstaack.
This is an image of planetary nebula NGC 7662, the Blue Snowball. Credit: Adam Block, Caelum Observatory.
This is a xenon 6 kW Hall thruster in operation at the NASA Jet Propulsion Laboratory. Credit: NASA/JPL-Caltech.
This is a color composite image of NGC 7662. Credit: Judy Schmidt.

In spacecraft propulsion, a Hall thruster is a type of ion thruster in which the propellant is accelerated by an electric field. Hall thrusters trap electrons in a magnetic field and then use the electrons to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the ions in the plume. Hall thrusters are sometimes referred to as Hall effect thrusters or Hall current thrusters. Hall thrusters are often regarded as a moderate specific impulse (1,600 s) space propulsion technology. Hall thrusters operate on a variety of propellants, the most common being xenon. Other propellants of interest include krypton, argon, bismuth, iodine, magnesium, and zinc.

At left are two images of the plasma associated with and a part of NGC 7662. The color of the nebula is very blue-green where the dominant light source is the 500.7 nm oxygen emission.

The second image is from the Hubble Space Telescope through three filters: F502N (blue), F555W (green), and F658N (red). The object is a planetary nebula (NGC 7662). A small star in the center has produced the nebula.


"The Hessdalen Light [HL] is an unexplained light usually seen in the Hessdalen valley in the municipality of Holtålen in Sør-Trøndelag county, Norway."[10]

"HL [may be] formed by a cluster of macroscopic Coulomb crystals in a plasma produced by the ionization of air and dust by alpha particles during radon decay in the dusty atmosphere."[11]

"HL are characterized mostly by white color and sometimes by red color. It occurs mostly at night, more often in the winter season and with a peak around midnight."[11]

Sun (star)[edit]

Main sources: Stars/Sun and Sun (star)



"Many CMEs have also been observed to be unassociated with any obvious solar surface activity"[13].

In the images at right, a CME, or "arcs rise above an active region on the surface of the Sun in this series of images taken by the STEREO (Behind) spacecraft on January 27, 2010. The arcs are plasma, superheated matter made up of moving charged particles (electrons and ions). Just as iron filings arc from one end of a magnet to another, the plasma is sliding in an arc along magnetic field lines. In a movie of STEREO observations made between January 26 and January 29, the dynamic streams were initially just over the Sun’s edge and readily spotted as the Sun rotated them more into view."[14]

"About mid-way through the movie clip, a small coronal mass ejection (a stream of charged particles from the Sun) shoots out and into space at about a million miles per hour, carrying some magnetic field with it. The [first] image shows the beginning of the coronal mass ejection, while the [second] image shows the solar matter leaving the Sun’s corona. Most coronal mass ejections are more bulbous and wide: this one is quite narrow and contained. Nonetheless, NASA solar scientists agree that its speed and characteristics suggest that it was indeed a non-typical coronal mass ejection."[14]

Solar clouds[edit]

The February 10, 1956, event "was observed at Sacramento Peak. A bright ball appears above the [Sun's] surface, grows in size and Hα brightness, and explodes upward and outward."[15]

Coronal clouds[edit]

Def. "[t]he luminous plasma atmosphere of the Sun or other star, extending millions of kilometres into space, most easily seen during a total solar eclipse"[16] is called a corona, or stellar corona.




Intergalactic medium[edit]

Coronal clouds of the hot intergalactic medium are likely in the Local Group and intergalactic medium, i.e., extragroup. The copious production of hot intragroup and intergalactic gas is a natural consequence of white dwarf-dominated halos.

"MHD turbulence, generated during cluster-cluster mergers, may be a source of particle reacceleration in the IGM."[18]

Acceleration may be "by compressible turbulence in galaxy clusters, where the interaction between turbulence and the IGM is mediated by plasma instabilities and maintained collisional at scales much smaller than the Coulomb mean free path. In this regime most of the energy of fast modes is channelled into the reacceleration of relativistic particles and the acceleration process approaches a universal behaviour being self-regulated by the back-reaction of the accelerated particles on turbulence itself."[18]

Relativistic "protons contribute to several percent (or less) of the cluster energy, consistent with the FERMI observations of nearby clusters, [...] compressible turbulence at the level of a few percent of the thermal energy can reaccelerate relativistic electrons at GeV energies, that are necessary to explain the observed diffuse radio emission in the form of giant radio halos."[18]


Main source: Technology
The surface of a MEMS device is cleaned with bright, blue oxygen plasma in a plasma etcher to rid it of carbon contaminants. (100mTorr, 50W RF) Credit: .

Plasma cleaning involves the removal of impurities and contaminants from surfaces through the use of an energetic plasma created from gaseous species. Gases such as argon and oxygen, as well as mixtures such as air and hydrogen/nitrogen are used. The plasma is created by using high frequency voltages (typically kHz to >MHz) to ionise the low pressure gas (typically around 1/1000 atmospheric pressure), although atmospheric pressure plasmas are now also common.


  1. Most of the particles in the universe are in a plasma.

See also[edit]


  1. Q-Z Luo, N. D'Angelo, R. L. Merlino (1998). Shock formation in a negative ion plasma. 5. Department of Physics and Astronomy. Retrieved 2011-11-20. 
  2. 2.0 2.1 CK Birdsall, A. Bruce Langdon (October 1, 2004). Plasma Physics via Computer Simulation. New York: CRC Press. pp. 479. ISBN 0-7503-1035-1. Retrieved 2011-12-17. 
  3. Fractal Models of Blue Jets, Blue Starters Show Similarity, Differences to Red Sprites. 
  4. A. S. Baranov (May 1, 2005). "Electromagnetic Instability of a Homogeneous Plasma in Interstellar Space". Technical Physics 50 (5): 595-602. doi:10.1134/1.1927214. Retrieved 2013-12-22. 
  5. "coronal mass ejection, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. June 21, 2013. Retrieved 2013-07-07. 
  6. Blue Jets & Blue Starters - the video. 
  7. The Role of the Space Shuttle Videotapes in the Discovery of Sprites, Jets, and Elves. GHCC: Lightning and Atmospheric Electricity Research. 
  8. Blue jets. 
  9. Victor P. Pasko. Fractal models of blue jets, blue starters show similarity, differences to red sprites. 
  10. "Hessdalen light". Wikipedia (San Francisco, California: Wikimedia Foundation, Inc). July 26, 2013. Retrieved 2013-08-02. 
  11. 11.0 11.1 G.S. Paiva, C.A. Taft (October 2010). "A hypothetical dusty plasma mechanism of Hessdalen lights". Journal of Atmospheric and Solar-Terrestrial Physics 72 (16): 1200-3. doi:10.1016/j.jastp.2010.07.022. Retrieved 2013-08-02. 
  13. David F. Webb, Timothy A. Howard (2012). "Coronal Mass Ejections: Observations". Living Reviews in Solar Physics 9: 3. Retrieved 2012-11-11. 
  14. 14.0 14.1 Paul Przyborski (February 13, 2010). Coronal Mass Ejection in late January 2010. NASA Earth Observatory. Retrieved 2012-11-26. 
  15. Harold Zirin (October 1964). "The Limb Flare of November 20, 1960: a Coronal Phenomenon". Astrophysical Journal 140 (10): 1216-35. doi:10.1086/148019. 
  16. "corona, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. May 9, 2012. Retrieved 2012-06-28. 
  18. 18.0 18.1 18.2 G. Brunetti, A. Lazarian (April 2011). "Particle reacceleration by compressible turbulence in galaxy clusters: effects of a reduced mean free path". Monthly Notices of the Royal Astronomical Society 412 (2): 817-24. doi:10.1111/j.1365-2966.2010.17937.x. Retrieved 2014-02-09. 

External links[edit]

{{Astronomy resources}}