[P-EM13] Dynamics of the Inner Magnetospheric System

[PEM13-06] Monitoring Fast Dynamics of Energetic Electrons from Low Altitudes

*Xiaojia Zhang¹、Weiqin Sun¹、Anton Artemyev²、Vassilis Angelopoulos² (1.The University of Texas at Dallas、2. Earth, Planetary, and Space Sciences, UCLA)

キーワード：Outer radiation belt, Energetic electron fluxes, ERG and ELFIN observations

One key element for space weather models is energetic electron fluxes in the inner magnetosphere and the outer radiation belt. Flux depletion is driven by various loss processes, mainly scattering into the atmosphere and magnetopause shadowing. Flux enhancement is driven by various acceleration processes, such as local wave-particle interactions, radial transport, and plasma sheet injections. Many of these processes operate on timescales shorter than a couple hours. Therefore, such mesoscale flux variations cannot be well traced by equatorial spacecraft with much longer orbital periods. In this study, we show an alternate way to monitor fast dynamics of energetic fluxes using high-energy resolution observations at low altitudes. To estimate the accuracy of this method, we compare energy, L-shell distributions of energetic electron fluxes measured by ELFIN CubeSats and the Global Positioning System (GPS) constellation, which provides a unique opportunity to probe sub-hour-scale flux variations. We further perform statistics on the energy, L-shell distributions measured by ELFIN and near-equatorial spacecraft (THEMIS and ERG) during conjunctions. Such a comparison allows us to derive coefficients to infer near-equatorial electron fluxes from low-altitude ELFIN measurements. These coefficients depend on particle energy and L-shell. We will also discuss how this new data set, as derived from ELFIN measurements, can be used generically to investigate mesoscale dynamics of energetic electron fluxes in the inner magnetosphere.