Radiation Belt Loss due to Energetic Electron Precipitation in Geomagnetic Storm associated with Corotating Interaction Regions

Thursday, 8 March 2018: 08:30
Longshot and Bogey (Hotel Quinta da Marinha)
Hilde Nesse Tyssøy1, Linn-Kristine Glesnes Ødegaard2, Johan Stadsnes3, Marit Irene Sandanger2 and Finn Søraas4, (1)University of Bergen, Birkeland Centre for Space Science (BCSS), Department of Physics and Technology, Bergen, Norway, (2)University of Bergen, Birkeland Centre for Space Science, Bergen, Norway, (3)Univ Bergen, Bergen, Norway, (4)University of Bergen, Bergen, Norway
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Abstract:
The processes leading to acceleration and loss of energetic electrons in the magnetosphere during geomagnetic storms have yet to be fully understood, and whether a geomagnetic storm will lead to enhanced or depleted fluxes of relativistic electrons is not always evident. We use the MEPED detectors on board the POES satellites to study the behavior of the radiation belt loss due to precipitating electrons with energy E>40 keV, E>100 keV, E>300 keV, and E>750keV during geomagnetic storms.

Applying a newly developed technique, we can derive the flux of electrons depositing their energy into the atmosphere (the bounce loss cone flux) from the horizontal and vertical detectors on each satellite. 41 isolated Corotating Interaction Region (CIR) storms were identified in the period 2006–2010 in the declining phase and near minimum in the solar activity cycle. By combining measurements from several satellites, we obtain a close to global view of the precipitating energetic electron fluxes, enabling us to study the relationship between the energetic electron precipitation and different geomagnetic indices and solar wind drivers.

Based on a superposed epoch analysis with solar wind parameters, geomagnetic indices, radiation belt fluxes, and precipitating electron fluxes, we find that the storms that have an increase in the precipitating flux of electrons with energy > 300 keV is characterized by an elevated solar wind velocity for a longer period compared to the storms that do not have an increase. Storms with increased precipitation of > 750 keV flux are distinguished by higher energy input from the solar wind quantified by the ε parameter, and corresponding higher geomagnetic activity. We aim to establish a quantitative link between high speed solar wind stream and energetic electron precipitation.

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