Heliophysics Science Division
TYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> Adolfo Vinas - Abstract

Gyrophased-bunched trapping of thermal electrons in the Earth's foreshock


Dr. Adolfo F.-Vi�as
Laboratory for Extraterrestrial Physics
NASA Goddard Space Flight Center

Recent WIND plasma electron observations upstream of the Earth's bow shock have revealed a sustained signature of non-gyrotropic electron distribution functions. Here we present a model of how to generate such distributions. Using PIC simulations we show that an anisotropic ion beam is capable of generating both low frequency MHD waves and high frequency whistler waves. The low frequency MHD wave modes in turn are able to generate non-gyrotropic protons whereas the high frequency whistler waves are capable of gyrophased-bunching electrons through wave trapping, providing a mechanism for such distributions upstream of the Earth's bow shock.