Electron Acceleration in the Heart of the Van Allen Radiation Belts

Author
Keywords
Abstract
The Van Allen radiation belts contain ultrarelativistic electrons trapped in Earth\textquoterights magnetic field. Since their discovery in 1958, a fundamental unanswered question has been how electrons can be accelerated to such high energies. Two classes of processes have been proposed: transport and acceleration of electrons from a source population located outside the radiation belts (radial acceleration) or acceleration of lower-energy electrons to relativistic energies in situ in the heart of the radiation belts (local acceleration). We report measurements from NASA\textquoterights Van Allen Radiation Belt Storm Probes that clearly distinguish between the two types of acceleration. The observed radial profiles of phase space density are characteristic of local acceleration in the heart of the radiation belts and are inconsistent with a predominantly radial acceleration process.
Year of Publication
2013
Journal
Science
Volume
341
Number of Pages
991-994
Date Published
07/2013
ISSN Number
0036-8075
URL
http://www.sciencemag.org/cgi/doi/10.1126/science.1237743
DOI
10.1126/science.1237743