Forecasting keV-electrons in the inner Earth's magnetosphere responsible for surface charging

Abstract:

Low energy (up to 100-200 keV) electron fluxes are very important to specify when hazardous satellite surface charging phenomena are considered. These electrons are the seed population, being further accelerated to MeV energies by various processes in the Earth’s radiation belts. Accurate modeling and forecasting of low energy electrons is very challengable, since the electron flux at the keV energies is largely determined by convective and substorm-associated electric fields and varies significantly with geomagnetic activity driven by the solar wind on the time scales on tens of minutes. We present the model for low energy (< 200 keV) electrons in the inner magnetosphere, which is the version of the Inner Magnetosphere Particle Transport and Acceleration model (IMPTAM) for electrons. This model has been operating online since March 2013 (http://fp7-spacecast.eu and imptam.fmi.fi). The model is driven by the real time solar wind and Interplanetary Magnetic Field (IMF) parameters with 1 hour time shift for propagation to the Earth’s magnetopause, and by the real time Dst index. The presented model provides the low energy electron flux at all L-shells and at all satellite orbits, when necessary. We present the model performance analysis (accumulated model output compared to GOES MAGED data) and demonstrate the model's forecasting abilities on several real space weather events. We discuss the recent advances we achieved for model's inputs such as solar wind-driven boundary conditions in the plasma sheet (based on THEMIS data) and introducing the electron lifetimes due to interactions with chorus and hiss waves. We show that the IMPTAM model for electrons provides very good forecast of keV-electrons in the inner magnetosphere.