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Session: Heliophysics and the Solar System

Name: Ms. Konstantina Thanasoula (National & Kapodistrian Univ. of Athens)
Coauthors: Katsavrias Christos (Department of Physics, National and Kapodistrian University of Athens, Greece)
Nasi Afroditi (Department of Physics, National and Kapodistrian University of Athens, Greece)
Daglis Ioannis A. (1.Department of Physics, National and Kapodistrian University of Athens, Greece. 2.Hellenic Space Center, Greece)
Balasis Georgios (IAASARS, National Observatory of Athens, Greece)
Sarris Theodore (Department of Electrical Engineering, Democritus University of Thrace, Greece)
Type: Poster
Title: The dependence of radial diffusion coefficients on solar/interplanetary drivers
Abstract:

Radial diffusion driven by Ultra Low Frequency (ULF) waves has been established as one of the most important mechanisms of the radiation belt dynamics because it contributes to relativistic electron enhancements and losses in the outer Van Allen belt. Many previous studies have investigated the dependence of ULF wave power spectral density and radial diffusion coefficients (DLL) on solar wind parameters. In this study, we conduct a statistical analysis of radial diffusion coefficients, which contributes to relativistic electron radial diffusion quantification, in order to look into their dependence on different solar/interplanetary drivers (25 events of Interplanetary Coronal Mass Ejections (ICMEs) and 46 events of Stream Interaction Regions (SIRs) of which the 16 events are SIRs with shock and the 30 events are SIRs without shock). Specifically, we study how the solar wind parameters influence the behavior of radial diffusion coefficients especially when the dynamic pressure of the solar wind is maximized. The data originate from the "SafeSpace" database, which was created using magnetic and electric field measurements by the THEMIS satellites in the 2011-2019 time period and includes radial diffusion coefficients (DLL) and ULF wave power spectral density (https://synergasia.uoa.gr/modules/document/?course=PHYS120). Our results indicate notable differences between ICME and SIR driven disturbances at the ratio of DLLE to DLLB. A significant energy dependence to the ratio of DLLE to DLLB is observed, which is further depending on the radial distance and the different mu values.