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 ?
These particles create intense radiation belts and auroras around the planet in a process similar to that on earth.
Juno will aim to investigate Jupiter's atmosphere, those intense radiation belts, and its magnetic field.
As the first significant discovery of the space age, the Van Allen radiation belts were detected in 1958 by Professor James Van Allen and his team at the University of Iowa and were found to be composed of an inner and outer belt extending up to 25,000 miles above Earth's surface.
Ultra-relativistic electrons in the Earth's outer radiation belt can exhibit pronounced variability in response to activity on the sun and changes in the solar wind, but the dominant physical mechanism responsible for radiation-belt electron acceleration has remained unresolved for decades.
The Van Allen Probes will explore the Van Allen Radiation Belts in the Earth's magnetosphere.
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.
But it will do so in an orbit around the planet's poles, ducking below the intense radiation belts that concentrate high-energy, sub-atomic particles around the equator.
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.
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.
The craft, crude even by the standards of just a few years later, transmitted data for three months, and led to the discovery of the Van Allen radiation belts, doughnut-shaped areas of charged particles that surround the Earth and have a major impact on satellite communications.