A Third Van Allen Radiation Belt Discovered Circling Earth

From Science 2.0:

Earth's radiation belts, called Van Allen belts, were discovered after the very first launches of satellites in 1958 by James Van Allen. Subsequent missions have observed parts of the belts but what causes such dynamic variation in the belts has remained something of a mystery. Seemingly similar storms from the sun have at times caused completely different effects in the belts, or have sometimes led to no change at all.

The Van Allen Probes consist of two identical spacecraft with a mission to map out this region, cataloging a wide range of energies and particles, and tracking the zoo of magnetic waves that pulse through the area, sometimes kicking particles up to such frenzied speeds that they escape the belts altogether. But they didn't discover something no one ever saw before - a third belt.

When the Relativistic Electron Proton Telescope (REPT) overlapped its observations with another mission called SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer), solar activity on the sun had sent energy toward Earth that caused the radiation belts to swell. The REPT instrument made observations of these new particles trapped in the belts, recording their high energies and the belts' increased size.

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