Van Allen probes (RBSP) measurement of the radiation belt dynamics

Sponsor: Dra. Ligia Alves da Silva

The Outer Radiation Belt consists mainly of high energy electrons (0.1-10 MeV) trapped in the Earth’s Magnetic Field. Its almost toroidal shape extends from ~3-10 Earth Radii (Re).


Figure 1: Electron energy flux at 3.6 MeV measured by the REPT Instrument on NASA’s Van Allen Probes (RBSP) spacecraft A with simultaneous  Solar Wind Speed (Vp), density (Np), Total Magnetic Field strength (Bt) and Interplanetary Magnetic Field (Bz; GSM). Data were obtained from the MAG and SWEPAM instruments on the ACE spacecraft via NOAA


The Figure (1) shows the energy flux of the 3.60 MeV electrons for the October 17th-28th (2014) period, observed by instruments aboard the NASA Van Allen Storm Probes. In the First two days the electron’s population was concentrated between 3.5-4.5 Re, presenting low energy flux (~105 cm-2s-1sr-1MeV-1). From day 19 on a re-population to high altitudes starts to take place. It becomes even more significant after the arrival of a solar wind high speed stream on Oct. 22nd (Vp). From day 23 on we can observe an increase of approximately 6 orders of magnitude in electron flux, persisting until day 28. It is noteworthy that between Oct. 19th to 28th  there were several intense Solar Flares emissions associated with the largest solar active region (AR 2192) in the last 25 years.

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