Large anisotropies of >60 MeV protons throughout the inner belt observed with the Van Allen Probes mission

TitleLarge anisotropies of >60 MeV protons throughout the inner belt observed with the Van Allen Probes mission
Publication TypeJournal Article
Year of Publication2014
AuthorsMazur, JE, O'Brien, TP, Looper, MD, Blake, JB
JournalGeophysical Research Letters
Volume41
Issue11
Pagination3738 - 3743
Date Published06/2014
KeywordsVan Allen Probes
AbstractWe report large directional anisotropies of >60 MeV protons using instrumentation on the Van Allen Probes. The combination of a spinning satellite and measurements from the Relativistic Proton Spectrometer instruments that are insensitive to protons outside the instrument field of view together yield a new look at proton radial gradients. The relatively large proton gyroradius at 60 MeV couples with the radial gradients to produce large (maximum ~10:1) flux anisotropies depending on (i) whether the proton guiding center was above or below the Van Allen Probes spacecraft and (ii) the sign of the local flux gradient. In addition to these newly measured anisotropies, below ~2000 km we report a new effect of systematically changing minimum altitude on some proton drift shells that further modulates the anisotropy caused by the atmosphere. This discovery may offer a new way of monitoring changes to the loss of inner belt protons into the Earth's atmosphere.
URLhttp://doi.wiley.com/10.1002/grl.v41.11http://doi.wiley.com/10.1002/2014GL060029
DOI10.1002/grl.v41.1110.1002/2014GL060029
Short TitleGeophys. Res. Lett.


Page Last Modified: July 30, 2014