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Science Meetings

Radiation Belts During Geomagnetic Storms Observed by Carmen/SAC-D
Dasso, S. and Lanabere, V. (17-Nov-15)

The van Allen radiation belts contain energetic particles, trapped by the geomagnetic field. Short term variability of these particle are determined by the geomagnetic activity, which is mainly determined by the conditions of the solar wind near Earth. Under normal conditions, the inner belt is extended near the equator from ~0.2 to ~2 terrestrial radii (R_E) from the surface, and the outer belt from ~3 R_E to ~9 R_E. These regions are highly dynamics, with typical time scales ranging from minutes to years. In particular, their properties are strongly affected by extreme space weather events, such as geomagnetic storms. These storms, generally triggered by transient events in the interplanetary medium, are associated with changes in both the composition and energy of the population of particles in the van Allen radiation belts. This variability is much more significant near some specific regions, such as the south Atlantic anomaly. During storm periods, the inner limit of the belt can reach levels so low as around 200 km above sea level. The inner belt contains large concentrations of electrons with energies larger than hundreds of keVs, and energetic protons with energies larger than 100 MeVs. The main aim of the present work is to characterize several aspects of the proton populations in the energy range of (13 - 190) MeV, and electrons in the range (0.25 - 3) MeV, at ~600 km of altitude, using observations from the detector ICARE-NG/CARMEN-1, aboard SAC-D. We quantify these particle fluxes and their variations (both temporal and spatial) and we present comparisons during calm and stormy period.