NASA | GSFC | Van Allen Probes | 2017 Mar 15
Van Allen Probes mission show that the fastest, most energetic electrons in the inner radiation belt are not present as much of the time as previously thought. The results are presented in a paper in the Journal of Geophysical Research and show that there typically isn’t as much radiation in the inner belt as previously assumed — good news for spacecraft flying in the region.
Past space missions have not been able to distinguish electrons from high-energy protons in the inner radiation belt. But by using a special instrument, the Magnetic Electron and Ion Spectrometer — MagEIS — on the Van Allen Probes, the scientists could look at the particles separately for the first time. What they found was surprising — there are usually none of these super-fast electrons, known as relativistic electrons, in the inner belt, contrary to what scientists expected. ...
The hidden dynamics of relativistic electrons (0.7–1.5 MeV) in the inner zone and slot region - S. G. Claudepierre et al
- Journal of Geophysical Research (online 15 Mar 2017) DOI: 10.1002/2016JA023719