Van Allen Probes tagged posts

This is an artist concept of accelerated electrons circulating in Earth’s Van Allen radiation belts. Credit: NASA’s Goddard Space Flight Center; Tom Bridgman, animator

Our planet is in the center of 2 immense, concentric doughnuts of powerful radiation: Van Allen radiation belts, which harbor swarms of charged particles that are trapped by Earth’s magnetic field. On March 17, 2015, an interplanetary shock – a shockwave created by the driving force of a coronal mass ejection, CME, from the sun – struck Earth’s magnetic field, the magnetosphere, triggering the greatest geomagnetic storm of the preceding decade. And NASA’s Van Allen Probes were there to watch the effects on the radiation belts.

One of the most common forms of space weather, a geomagnetic storm describes any event in which the...

During periods when geomagnetic storms affect Earth, new low-energy protons (with energy of tens of thousands of electronvolts, or keV; shown here in magenta) enter the near-Earth region, enhancing the preexisting ring current (orange). Credit: Johns Hopkins APL

New findings based on a year’s worth of observations from NASA’s Van Allen Probes have revealed that the ring current – an electrical current carried by energetic ions that encircles our planet – behaves in a much different way than previously understood. The ring current has long been thought to wax and wane over time, but the new observations show that this is true of only some of the particles, while other particles are present consistently.

Using data gathered by the Radiation Belt Storm Probes Ion Composition Experiment, or RB...