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Encyclopedia > Van Allen radiation belt
Van Allen radiation belts
Van Allen radiation belts

The Van Allen Radiation Belt is a torus of energetic charged particles (plasma) around Earth, held in place by Earth's magnetic field. The Van Allen belts are closely related to the polar aurora where particles strike the upper atmosphere and fluoresce. Image File history File links Van_Allen_radiation_belt. ... Image File history File links Van_Allen_radiation_belt. ... In geometry, a torus (pl. ... Lightning is the electric breakdown of air by strong electric fields, or a plasma, which causes an energy transfer from the electric field to heat, mechanical energy (the random motion of air molecules caused by the heat), and light. ... In physics, a charged particle is a particle with an electric charge. ... For other uses, see Plasma. ... This article is about Earth as a planet. ... Magnetic field lines shown by iron filings In physics, the space surrounding moving electric charges, changing electric fields and magnetic dipoles contains a magnetic field. ... Aurora borealis Polar aurorae are optical phenomena characterized by colorful displays of light in the night sky. ... “Air” redirects here. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized Cadmium selenide (CdSe) quantum dots. ...


The presence of a radiation belt had been proposed by Nicholas Christofilos [1] prior to the Space Age and was confirmed by the Explorer I on January 31, 1958, and Explorer III missions, under Dr.James Van Allen at the University of Iowa. The trapped radiation was first mapped out by Sputnik 3, Explorer IV, Pioneer III and Luna 1. Nicholas Constantine Christofilos (Νικόλαος Χριστοφίλου) (December 16, 1916 - September 24, 1972) was a Greek-American physicist. ... The Space Shuttle takes off on a manned mission to space. ... Explorer-I, officially Satellite 1958 Alpha (and sometimes referred to as Explorer 1), was the first Earth satellite of the United States, having been launched at 10:48pm EST on January 31 (03:48 on 1 February in GMT), 1958, as part of the United States program for the International... is the 31st day of the year in the Gregorian calendar. ... Year 1958 (MCMLVIII) was a common year starting on Wednesday (link will display full calendar) of the Gregorian calendar. ... Mission Description Explorer-III was nearly identical to Explorer I in design and mission. ... James Van Allen at National Air & Space Museum (NASM), 1981, Photo courtesy of NASM. Explorer I model and Pioneer H probe in background James Alfred Van Allen (September 7, 1914 – August 9, 2006) was an American space scientist at the University of Iowa. ... The University of Iowa, also commonly called Iowa or U of I, is a major national research university located on a campus in Iowa City, Iowa, USA, on the banks of the Iowa River in East Central Iowa. ... Sputnik 3 (Russian: , Satellite 3) was a Soviet satellite launched on May 15, 1958 from Baikonur cosmodrome by a modified R-7/SS-6 ICBM. It was a research satellite to explore the upper atmosphere and the near space. ... Explorer 4 was a US satellite launched on July 26, 1958. ... Pioneer III Pioneer 3 was a spin stabilized spacecraft launched by the U.S. Army Ballistic Missile agency in conjunction with NASA. The spacecraft was intended as a lunar probe, but failed to go past the Moon and into a heliocentric orbit as planned, but did reach an altitude of... Luna 1 is the first spacecraft to reach the vicinity of the Moon and the first of the Luna programme of Soviet automatic interplanetary stations successfully launched in the direction of the Moon. ...


Energetic electrons form two distinct radiation belts, while protons form a single belt. Within these belts are particles capable of penetrating about 1 g/cm2 [2] of shielding (e.g., 1 millimetre of lead). BIC pen cap, about 1 gram. ... A centimetre (American spelling centimeter, symbol cm) is a unit of length that is equal to one hundredth of a metre, the current SI base unit of length. ... A millimetre (American spelling: millimeter, symbol mm) is an SI unit of length that is equal to one thousandth of a metre. ... For Pb as an abbreviation, see PB. General Name, Symbol, Number lead, Pb, 82 Chemical series Post-transition metals or poor metals Group, Period, Block 14, 6, p Appearance bluish gray Standard atomic weight 207. ...


The term Van Allen Belts refers specifically to the radiation belts surrounding Earth; however, similar radiation belts have been discovered around other planets. The Sun does not support long-term radiation belts. The Earth's atmosphere limits the belts' particles to regions above 200-1,000 km,[3] while the belts do not extend past 7 Earth radii RE.[3] The belts are confined to an area which extends about 65°[3] from the celestial equator. This article is about Earth as a planet. ... This article is about the astronomical term. ... Sol redirects here. ... A kilometer (Commonwealth spelling: kilometre), symbol: km is a unit of length in the metric system equal to 1,000 metres (from the Greek words χίλια (khilia) = thousand and μέτρο (metro) = count/measure). ... Because the Earth, like all planets, is not a perfect sphere, the radius of Earth can vary at different places on the surface. ... This article describes the unit of angle. ... The celestial sphere is divided by the celestial equator. ...


An upcoming NASA mission, Radiation Belt Storm Probes will go further and gain scientific understanding (to the point of predictability) of how populations of relativistic electrons and ions in space form or change in response to changes in solar activity and the solar wind. The Radiation Belt Storm Probes (RBSP) is a NASA mission under the Living With a Star (LWS) program. ...

Contents

Outer belt

Laboratory simulation of the Van Allen belts' influence on the Solar Wind; these auroral-like Birkeland currents were created by the scientist Kristian Birkeland in his terrella, a magnetized anode globe in an evacuated chamber.
Laboratory simulation of the Van Allen belts' influence on the Solar Wind; these auroral-like Birkeland currents were created by the scientist Kristian Birkeland in his terrella, a magnetized anode globe in an evacuated chamber.

The large outer radiation belt extends from an altitude of about 13,000–65,000 km (2 to 10 Earth radii) above the Earth's surface, and has its greatest intensity between 14,500 and 19,000 km. The outer belt consists mainly of high energy (0.1–10 MeV) electrons trapped by the Earth's magnetosphere. The gyroradii for energetic protons would be large enough to bring them into contact with the Earth's atmosphere. The electrons here have a high flux and at the outer edge (close to the magnetopause), where geomagnetic field lines open into the geomagnetic "tail", fluxes of energetic electrons can drop to the low interplanetary levels within about 100 km (a decrease by a factor of 1,000). Image File history File links Birkeland-anode-globe-fig259. ... Image File history File links Birkeland-anode-globe-fig259. ... The aurora on Jupiter, powered by Jovian Birkeland currents [Ref. ... Kristian Birkeland Kristian Birkeland (December 13, 1867 - June 15, 1917) was born in Christiania (Oslo today) and wrote his first scientific paper at the age of 18. ... Kristian Birkelands magnetised terrella. ... A magnetosphere is the region around an astronomical object in which phenomena are dominated or organized by its magnetic field. ... The gyroradius (also known as radius of gyration or cyclotron radius) defines the radius of the circular motion of a charged particle in the presence of a magnetic field. ... flux in science and mathematics. ... A magnetopause flows along the boundary between a magnetic field, (see: magnetosphere) and surrounding plasma. ...


The trapped particle population of the outer belt is varied, containing electrons and various ions. Most of the ions are in the form of energetic protons, but a certain percentage are alpha particles and O+ oxygen ions, similar to those in the ionosphere but much more energetic. This mixture of ions suggests that ring current particles probably come from more than one source. An alpha particle is deflected by a magnetic field Alpha particles or alpha rays are a form of particle radiation which are highly ionizing and have low penetration. ... Relationship of the atmosphere and ionosphere The ionosphere is the uppermost part of the atmosphere, distinguished because it is ionized by solar radiation. ... A ring current is an electric current carried by charged particles trapped in a planets magnetosphere. ...


The outer belt is larger than the inner belt, and its particle population fluctuates widely. Energetic (radiation) particle fluxes can increase and decrease dramatically as a consequence of geomagnetic storms, which are themselves triggered by magnetic field and plasma disturbances produced by the Sun. The increases are due to storm-related injections and acceleration of particles from the tail of the magnetosphere. A geomagnetic storm is a temporary disturbance of the Earths magnetosphere. ...


There is debate as to whether the outer belt was discovered by the US Explorer IV or the USSR Sputnik II/III. Motto: (Out Of Many, One) (traditional) In God We Trust (1956 to date) Anthem: The Star-Spangled Banner Capital Washington D.C. Largest city New York City None at federal level (English de facto) Government Federal constitutional republic  - President George Walker Bush (R)  - Vice President Dick Cheney (R) Independence from... Explorer 4 was a US satellite launched on July 26, 1958. ... Sputnik 2 was the second spacecraft launched into Earth orbit, at 19:12:00 on November 3, 1957, and was the first spacecraft to carry biological material. ... Mission profile Sputnik 3 was a Soviet satellite launched on May 15, 1958 from Baikonur cosmodrome by a modified R-7/SS-6 ICBM. It was a research satellite to explore the upper atmosphere and the near space. ...


Inner belt

The inner Van Allen Belt extends from an altitude of 700–10,000 km (0.1 to 1.5 Earth radii) above the Earths surface, and contains high concentrations of energetic protons with energies exceeding 100 MeV and electrons in the range of 100's of keV, trapped by the strong (relative to the outer belts) magnetic fields in the region.


It is believed that protons of energies exceeding 50 MeV in the lower belts at lower altitudes are the result of the beta decay of neutrons created by cosmic ray collisions with nuclei of the upper atmosphere. The source of lower energy protons is believed to be proton diffusion due to changes in the magnetic field during geomagnetic storms. [4] In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 940 MeV/c² (1. ...


Due to the slight offset of the belts from Earth's geometric center, the inner Van Allen belt makes its closest approach to the surface at the South Atlantic Anomaly. The Van Allen radiation belts and the point of the South Atlantic Anomaly. ...


Impact on space travel

Solar cells, integrated circuits, and sensors can be damaged by radiation. In 1962, the Van Allen belts were temporarily amplified by a high-altitude nuclear explosion (the Starfish Prime test) and several satellites ceased operation. Geomagnetic storms occasionally damage electronic components on spacecraft. Miniaturization and digitization of electronics and logic circuits have made satellites more vulnerable to radiation, as incoming ions may be as large as the circuit's charge. Electronics on satellites must be hardened against radiation to operate reliably. The Hubble Space Telescope, among other satellites, often has its sensors turned off when passing through regions of intense radiation. A solar cell, made from a monocrystalline silicon wafer A solar cell or photovoltaic cell is a device that converts light energy into electrical energy. ... Integrated circuit of Atmel Diopsis 740 System on Chip showing memory blocks, logic and input/output pads around the periphery Microchips with a transparent window, showing the integrated circuit inside. ... Not to be confused with censure, censer, or censor. ... Radiation as used in physics, is energy in the form of waves or moving subatomic particles. ... Year 1962 (MCMLXII) was a common year starting on Monday (the link is to a full 1962 calendar) of the Gregorian calendar. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 kilometers (11 mi) above the hypocenter A nuclear weapon derives its destructive force from nuclear reactions of fusion or fission. ... The debris fireball stretching along Earths magnetic field [1] with air-glow aurora as seen at 3 minutes from a KC-135 surveillance aircraft The flash created by the explosion as seen through heavy cloud cover from Honolulu 1,300 km away Another view of Starfish Prime through thin... For other uses, see Satellite (disambiguation). ... A geomagnetic storm is a temporary disturbance of the Earths magnetosphere. ... A digital circuit that acts as a binary clock, hand-wired on a series of breadboards Digital electronics are electronics systems that use digital signals. ... This article is about the engineering discipline. ... A logic gate performs a logical operation on one or more logic inputs and produces a single logic output. ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... Microelectronics designed for environments with high levels of ionizing radiation have special design challenges. ... The Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble. ...


An object satellite shielded by 3 mm of aluminium will receive about 2,500 rem (25 Sv) per year.[5] A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ... “Aluminum” redirects here. ... The Röntgen equivalent in man or rem (symbol rem) is a unit of radiation dose. ... The sievert (symbol: Sv) is the SI derived unit of dose equivalent. ... A year (from Old English gēr) is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ...


Causes

Simulated Van Allen Belts generated by a plasma thruster in tank #5 Electric Propulsion Laboratory at the then-called Lewis Research Center, Cleveland Ohio,
Simulated Van Allen Belts generated by a plasma thruster in tank #5 Electric Propulsion Laboratory at the then-called Lewis Research Center, Cleveland Ohio,

It is generally understood that the inner and outer Van Allen belts result from different processes. The inner belt, consisting mainly of energetic protons, is the product of the decay of albedo neutrons which are themselves the result of cosmic ray collisions in the upper atmosphere. The outer belt consists mainly of electrons. They are injected from the geomagnetic tail following geomagnetic storms, and are subsequently energized though wave-particle interactions. Particles are trapped in the Earth's magnetic field because it is basically a magnetic mirror. Particles gyrate around field lines and also move along field lines. As particles encounter regions of stronger magnetic field where field lines converge, their "longitudinal" velocity is slowed and can be reversed, reflecting the particle. This causes the particle to bounce back and forth between the earth's poles, where the magnetic field increases. Image File history File links Size of this preview: 750 × 600 pixelsFull resolution (1500 × 1200 pixel, file size: 120 KB, MIME type: image/jpeg) Simulated Van Allen Belts generated by plasma thruster in tank #5 Electric Propulsion Laboratory at the Lewis Research Center, Cleveland Ohio, now John H. Glenn Research... Image File history File links Size of this preview: 750 × 600 pixelsFull resolution (1500 × 1200 pixel, file size: 120 KB, MIME type: image/jpeg) Simulated Van Allen Belts generated by plasma thruster in tank #5 Electric Propulsion Laboratory at the Lewis Research Center, Cleveland Ohio, now John H. Glenn Research... A plasma propulsion engine is an engine which uses accelerated plasma for propulsion. ... The Glenn Research Center is located in Cleveland, Ohio between Cleveland Hopkins International Airport and the Metropark. ... The two-stream instability is a very common instability in plasma physics. ... A magnetic mirror is a magnetic field configuration where the field strength changes when moving along a field line. ...


A gap between the inner and outer Van Allen belts, sometimes called safe zone or safe slot, is caused by the very low frequency (VLF) waves which scatter particles in pitch angle which results in the loss of particles to the atmosphere. Solar outbursts can pump particles into the gap but they drain again in a matter of days. The radio waves were originally thought to be generated by turbulence in the radiation belts, but recent work by James Green of the NASA Goddard Space Flight Center comparing maps of lightning activity collected by the Micro Lab 1 spacecraft with data on radio waves in the radiation-belt gap from the IMAGE spacecraft suggests that they're actually generated by lightning within Earth's atmosphere. The radio waves they generate strike the ionosphere at the right angle to pass through it only at high latitudes, where the lower ends of the gap approach the upper atmosphere. These results are still under scientific debate. The pitch angle of a charged particle is the angle between the particles parrallel motion the local magnetic field. ... James Stephen Green (February 28, 1817 - January 19, 1870 was a United States Representative and Senator from Missouri. ... Aerial view of Goddard Space Flight Center. ... It has been suggested that this article or section be merged into image (disambiguation). ...


There have been nuclear tests in space that have caused artificial radiation belts. Starfish Prime, a high altitude nuclear test created an artificial radiation belt that damaged or destroyed as many as one third of the satellites in low earth orbit at the time. Thomas Gold has argued that the outer belt is left over from the aurora while Alex Dessler has argued that the belt is a result of volcanic activity. The debris fireball stretching along Earths magnetic field [1] with air-glow aurora as seen at 3 minutes from a KC-135 surveillance aircraft The flash created by the explosion as seen through heavy cloud cover from Honolulu 1,300 km away Another view of Starfish Prime through thin... Thomas Gold (May 22, 1920 – June 22, 2004) was an Austrian astrophysicist, a professor of astronomy at Cornell University, and a member of the US National Academy of Sciences. ... Aurora borealis Polar aurorae are optical phenomena characterized by colorful displays of light in the night sky. ... For other uses, see Volcano (disambiguation). ...


In another view, the belts could be considered a flow of electric current that is fed by the solar wind. With the protons being positive and the electrons being negative, the area between the belts is sometimes subjected to a current flow, which "drains" away. The belts are also thought to drive auroras, lightning and many other electrical effects.


Removal

The belts are a hazard for artificial satellites and moderately dangerous for human beings, difficult and expensive to shield against.


There is a proposal by the late Robert L. Forward called HiVolt which may be a way to drain at least the inner belt to 1% of its natural level within a year. The proposal involves deploying highly electrically charged tethers in orbit. The idea is that the electrons would be deflected by the large electrostatic fields and intersect the atmosphere and harmlessly dissipate. Robert Lull Forward commonly known as Robert L. Forward (August 15, 1932 - September 21, 2002) was a United States physicist and science fiction writer. ... HiVOLT (acronym for High Voltage Orbiting Long Tether) is a concept proposed by Robert Hoyt and Robert L. Forward for removing the radiation fields of the Van Allen radiation belts that surround the Earth. ...


Some scientists, however, theorize that the Van Allen belts carry some additional protection against solar wind, meaning that a weakening of the belts could harm electronics and organisms; and that they may influence the Earth's telluric current, so that dissipating the belts could influence the behavior of Earth's magnetic poles. The plasma in the solar wind meeting the heliopause The solar wind is a stream of charged particles (i. ... A telluric current is an electric current in the Earth (both land and sea). ...


References in Popular Culture

  • In a Halloween special of The Simpsons (The "Attack of the 50-foot Eyesores" section of "Treehouse of Horror VI"), a radio broadcast warns Homer that, "Astronomers from Tacoma to Vladivostok have just reported an ionic disturbance in the vicinity of the Van Allen Belt. Scientists are recommending that necessary precautions be taken." These cause large advertising logos to come to life and cause havoc and destruction across Springfield.
  • In the cartoon The Adventures of Jimmy Neutron, an episode titled "The 'N' Men" (spoof of the X-Men) had Jimmy and his friends careening out of control through the Van Allen radiation belt, giving them all superpowers based on what each was doing at the moment they went through the radiation belt. This situation parodies the origins of the Fantastic Four.
  • In the anime series The Vision of Escaflowne, the two lead protagonists from the mysterious world above the Earth, Gaea, are named Van and Allen. Whether or not this has some connection is only known to the director Kazuki Akane.
  • In Osamu Tezuka's manga series "Astro Boy", Astro Boy uses the Van Allen Belt to destroy parasites from outer space.

Simpsons redirects here. ... Treehouse of Horror VI is the sixth episode of The Simpsons seventh season, as well as the sixth Halloween episode. ... This article is about the original film. ... The Adventures of Jimmy Neutron: Boy Genius is a spin-off of the Oscar-nominated computer-animated movie; Jimmy Neutron: Boy Genius, first officially aired in September 2002. ... The X-Men are a group of comic book superheroes featured in Marvel Comics. ... For other uses, see Fantastic Four (disambiguation). ... Original run April 2, 1996 – September 24, 1996 No. ... Kazuki Akane (赤根和樹 Akane Kazuki) is a well-known director of Japanese animation. ... This article is about the manga artist and animator. ... This article is about the 1960s series and manga. ...

References

  1. ^ See "Trapped Radiation -- History" by Dr. David P. Stern and Dr. Mauricio Peredo
  2. ^ The Radiation Belt and Magnetosphere by Wilmot Hess (1968)
  3. ^ a b c Introduction to Geomagnetically Trapped Radiation by Martin Walt (1994)
  4. ^ Tascione, Thomas F. (1994). Introduction to the Space Environment, 2nd. Ed.. Malabar, Florida USA: Kreiger Publishing CO.. ISBN 0-89464-044-5. 
  5. ^ Ptak, Andy (1997). Ask an Astrophysicist. NASA GSFC. Retrieved on 2006-06-11.

The Radiation Belt and Magnetosphere is a book written by Wilmot Hess in 1968. ... Wilmot N. Hess is a retired Associate Director of the US Department of Energy, first elected in 1976. ... Year 1968 (MCMLXVIII) was a leap year starting on Monday (link will display full calendar) of the Gregorian calendar. ... One might be looking for Stephen Martin Walt (Political Science). ... Year 1994 (MCMXCIV) The year 1994 was designated as the International Year of the Family and the International Year of the Sport and the Olympic Ideal by the United Nations. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 162nd day of the year (163rd in leap years) in the Gregorian calendar. ...

See also

L-shell Plot showing a view from space of L-shells 1. ...


External links

  • NASA Radiation Belt Storm Probe Mission

  Results from FactBites:
 
Van_Allen_radiation_belt (1269 words)
Laboratory simulation of the Van Allen belts' influence on the Solar Wind; these auroral-like Birkeland currents were created by the scientist Kristian Birkeland in his terrella, a magnetised anode globe in an evacutated chamber.
In 1962, the Van Allen belts were temporarily amplified by a high-altitude nuclear explosion (the Starfish Prime test) and several satellites ceased operation.
2 : The Radiation Belt and Magnetosphere by Wilmot Hess (1968)
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