Simulations of the inner magnetospheric energetic electrons using theIMPTAM-VERB coupled model

TL;DR

This paper introduces a coupled simulation model combining IMPTAM and VERB-3D to accurately predict energetic electron fluxes in Earth's inner magnetosphere during storm events, validated against satellite data.

Contribution

The study presents the first coupling of IMPTAM and VERB-3D models, enabling satellite-data-independent, accurate forecasting of energetic electron dynamics during geomagnetic storms.

Findings

The coupled model reproduces storm-time electron flux evolution within ~0.5 orders of magnitude.

Including low energy electron dynamics enhances flux predictions near the inner belt.

Magnetopause losses significantly reduce electron fluxes at low L* regions.

Abstract

In this study, we present initial results of the coupling between the Inner Magnetospheric Particle Transport and Acceleration Model (IMPTAM) and the Versatile Electron Radiation Belt (VERB-3D) code. IMPTAM traces electrons of 10 - 100 keV energies from the plasma sheet (L = 9 Re) to inner L-shell regions. The flux evolution modeled by IMPTAM is used at the low energy and outer L* computational boundaries of the VERB code (assuming a dipole approximation) to perform radiation belt simulations of energetic electrons. The model was tested on the March 17th, 2013 storm, for a six-day period. Four different simulations were performed and their results compared to satellites observations from Van Allen probes and GOES. The coupled IMPTAM-VERB model reproduces evolution and storm-time features of electron fluxes throughout the studied storm in agreement with the satellite data (within ~0.5 orders of magnitude). Including dynamics of the low energy population at L* = 6.6 increases fluxes closer to the heart of the belt and has a strong impact in the VERB simulations at all energies. However, inclusion of magnetopause losses leads to drastic flux decreases even below L* = 3. The dynamics of low energy electrons (max. 10s of keV) do not affect electron fluxes at energies >= 900 keV. Since the IMPTAM-VERB coupled model is only driven by solar wind parameters and the Dst and Kp indexes, it is suitable as a forecasting tool. In this study, we demonstrate that the estimation of electron dynamics with satellite-data-independent models is possible and very accurate.