Estimates of Total Radiation Belt Electron Content (TRBEC) and its Time Evolution using the RBSP-ECT Instrument Suite on the Van Allen Probes Mission
Abstract
Using measurements from the two-spacecraft Van Allen Probes mission we estimate the total radiation belt electron content (TRBEC) as a simple, global quantitative measure of radiation belt intensity. The two identically-instrumented spacecraft provide comprehensive energy and pitch angle coverage of radiation belt electrons near the magnetic equator throughout the inner magnetosphere, an advantage over earlier studies by Baker et al. (2004) and Selesnick and Kanekal (2009) that estimated similar quantities in LEO or in high-altitude polar orbits. We use electron measurements from the Radiation Belt Storm Probes (RBSP) Energetic Particle, Composition, and Thermal Plasma (ECT) suite to identify both the electron seed populations (a few 10's to a few 100's keV) as well as radiation belt electron populations (> ~ 500 keV) with the Magnetic Electron Ion Spectrometer (MagEIS) and the Relativistic Electron Proton Telescope (REPT) sensors. MagEIS provides the electron seed population measurements; MagEIS and REPT together provide the core radiation belt and ultra-relativistic electron populations. Using energy-resolved, locally-measured pitch angle distributions of electrons as a function of L, we estimate the equatorial distribution and then integrate the electrons over energy and pitch angle throughout the spatial volume to establish the TRBEC for both the electron seed and the core populations. Finally, we show how TRBEC varies as a function of time over the course of the mission, compare these variations to other quantitative measures of inner magnetospheric dynamism (e.g., Dst) and solar wind drivers, compare the seed to core TRBEC values and its time evolution, as well as compare to prior quantitative estimates of radiation belt electron content.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMSM24B..01S
- Keywords:
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- 2774 MAGNETOSPHERIC PHYSICS Radiation belts;
- 2720 MAGNETOSPHERIC PHYSICS Energetic particles: trapped;
- 2716 MAGNETOSPHERIC PHYSICS Energetic particles: precipitating;
- 2740 MAGNETOSPHERIC PHYSICS Magnetospheric configuration and dynamics