Talk about "VAN ALLEN BELT"

CHARGED PARTICLE ARRANGED IN REGION AROUND THE EARTH

The Van Allen Belt is a region about 700 to 60,000 km above the surface of earth which is populated by energetic charged particles.The shape of the region is like a torus or a doughnut and the charged particle which exist in the region are those which have been trapped by the earth magnetic field. This is closely related to the phenomenon of the auroras in the polar region-bright lights seen because charged particle from outer space hit the outer atmosphere and radiate light in the process. this belt was discovered by J.Van Allen in 1958 using the explorer stat-elite.

There are two distinct torus shaped belts-the inner and the outer one-with density which are a maximum at the equatorial latitudes and which drop off to zero beyond latitudes of approximately 60 in each hemisphere.
The outer belt,roughly in the region of 20,000 to 60,000 KM above the surface of the earth, consist of very energetic particles.These are mostly electrons but also consists of charged ions.The inner belt,approximately extending from 700 to 10,000 KM above the earth, predominately consists of non relativistic protons and electrons.

The gap between the Outer and Inner belts arises out of the interaction of low frequency radio waves with the charged particles in the region.Charged particle that accumulate there interact with the radio waves in a way that causes them to be ejected from that region.Various sources of radio waves have been produced.

The charged particle that populates the inner and outer Van Allen belts do not originated from the same source.the electron which dominates the outer belts are injected into the outer region during geomagnetic storms.The proton,which dominates the inner belts are products of neutron decay after being created in the collisions of the cosmic rays with the air molecules in the upper atmosphere.

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