AGS-PRF: The Exit of Energetic Particles from the Earth's Magnetosphere

Walsh Brian M, Boston MA

Investigators

Abstract

This project will analyze observations of energetic particles in the region of Earth's magnetopause and magnetosheath. It will study the processes that lead to the transport of plasma out of the magnetosphere and into the solar wind. The observations will come from the five THEMIS spacecraft. The changing orbits of the spacecraft provide several useful configurations allowing for simultaneous measurements of source and loss populations at different radial locations along the magnetopause. Observations have also been made where multiple spacecraft pass through similar places along the magnetopause at similar times which makes it possible to study small-scale temporal and spatial structures. Mechanisms that may lead to plasma loss from the magnetosphere include magnetic reconnection, particle drifts due to gradients in the magnetic field and diffusion. The observations will be compared with the Fok Radiation Belt Environment (RBE) model to test if loss rates from the model are consistent with observations under different conditions. Quantifying the conditions under which energetic particles are lost through the dayside magnetopause is an important aspect in understanding the dynamics of Earth's radiation belt. This is a topic that has relevance to our understanding of space weather.