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Session: Heliophysics and the Solar System

Name: Ms. Alexandra Triantopoulou (National & Kapodistrian Univ. of Athens)
Coauthors: Nasi Afroditi (NKUA, Greece)
Katsavrias Christos (NKUA, Greece)
Sandberg Ingmar (SPARC & Aerospace Science and Technology, NKUA, Greece)
Daglis Ioannis A. (NKUA, Greece & Hellenic Space Center, Greece)
Type: Poster
Title: Impact of high-speed solar wind streams on the dynamic variations of the electron population in the outer Van Allen belt
Abstract:

More than half a century after the discovery of Van Allen radiation belts, their dynamics are still not fully understood. The variability of the outer radiation belt electrons is related to geospace disturbances due to the interaction of solar wind with the terrestrial magnetosphere. The relativistic and ultra-relativistic electron population can be enhanced or depleted depending on the balance of the various acceleration and loss mechanisms. This variability depends significantly on the solar wind driver type. One of the most common solar wind drivers that affect, amongst others, the electrons of the outer radiation belt is the High-Speed Streams (HSSs) following Stream Interaction Regions (SIRs). Their effect on the various energetic electron populations is a major theme of space research. In this work, we examine the electron phase space density (PSD) during 30 SIRdriven events that occurred during the RBSP era (2012-2018), in terms of superposed epoch analysis (SEA), for seed, relativistic and ultra-relativistic electrons (μ=100, 1000, 5000 MeV/G). Furthermore, we examine three distinct values of the second adiabatic invariant (K=0.03, 0.09, 0.15 G1/2RE) in order to compare the differences between local acceleration and radial diffusion. In addition, we selected the time of maximum solar wind pressure (Pswmax) as the zero epoch time for all events, with the aim of extracting a statistical study, through time and radial profiles, of the response of the outer belt electron population on this solar wind driver