radiation belts


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radiation belts

One or more doughnut-shaped regions in the magnetosphere of a planet in which energetic electrons and the ionized nuclei of atoms, chiefly protons from hydrogen atoms, are trapped by the planet's magnetic field. The particles within the belt, whose axis is the magnetic axis of the planet, spiral along magnetic field lines, traveling backward and forward between reflections which occur as they approach the magnetic poles. This motion produces synchrotron emission from the particles. The particles are either captured from the solar wind or are formed by collisions between cosmic rays and atoms or ions in the planet's outer atmosphere.

The Earth, Jupiter, Saturn, Uranus, and Neptune are all known to possess radiation belts. The magnetic field of Mercury appears to be too weak to sustain belts. The radiation belts of Jupiter are many times more intense than the Van Allen radiation belts of the Earth and pose a threat to spacecraft systems in the vicinity of the planet.

References in periodicals archive ?
Juno will aim to investigate Jupiter's atmosphere, those intense radiation belts, and its magnetic field.
The myth that a dynamo causes Earth's magnetic field is replaced by a lost formula derived by Gauss for the origin of magnetic force, which also explains the origin of Earth's ionospheric radiation belts. Maxwell had suppressed Gauss's formula as "conflicting with the Energy Conservation 'Law'." The author updates his 1973 climate study predicting that Global Warming would expand Earth's desert belts poleward, like the Sahara grew with post-Ice Age warming.
The NASA delegation, along with Ambassador Noah Mamet and other embassy personnel, first met with the host nation's ministers of planning and foreign affairs, and officials of NASA's Argentine counterpart, with whom they signed the agreement providing Argentine assistance with data downlinks and analysis for two NASA probes that are studying Earth's radiation belts.
The barrier to the particle motion was discovered in the Van Allen radiation belts, two doughnut-shaped rings above Earth that are filled with high-energy electrons and protons, said Distinguished Professor Daniel Baker, director of CU-Boulder's Laboratory for Atmospheric and Space Physics (LASP).
Discovering the processes that control the formation and ultimate loss of these electrons in the Van Allen radiation belts - the rings of highly charged particles that encircle the Earth at a range of about 1,000 to 50,000 kilometers above the planet's surface - is a primary science objective of the recently launched NASA Van Allen Probes mission.
It also has its own magnetic field, offering protection against Jupiter's powerful radiation belts, and an ancient surface littered with many types of crater.
One of the concerns for astronauts who will visit both of these environments is the health threat from deep space radiation, which includes high-energy galactic cosmic rays (GCRs), solar proton events (solar flares), gamma rays (from black holes) and radiation belts encircling earth and other celestial bodies.
Juno will then spend one year cycling inside the giant planet's deadly radiation belts, far closer than any previous orbiting spacecraft.
It confirmed that the moon had only a tiny radiation field and, so far as could be observed, no radiation belts. The spacecraft had no propulsion system of its own and the third and final stage of its propelling rocket crashed on the moon about half an hour after Luna 2 itself.
In a magnetic storm the Van Allen radiation belts (the charged plasma particles surrounding the Earth) are rearranged, creating a doughnut that carries a ring current of 100 kiloelectronvolt plasma around the Earth.
Uman Inan, an electrical engineering professor, volunteered to equip the satellites with devices capable of measuring radiation belts between Earth and the moon.
The department had its own satellite, and its chairman was James Van Allen, who discovered the Earth-girdling radiation belts that later were named after him.