The goal of this project is to create a comprehensive model of the inner magnetosphere that includes the interactions of the plasmasphere, the ring current and the radiation belts. The model will be an enhancement of the Comprehensive Ring Current Model (CRCM) and the Radiation Belt Environment (RBE) model. The coupled model will include the processes by which particles are accelerated, the loss and transport processes and will include a self-consistent description of the electric and magnetic fields.
The project will examine how the inner magnetosphere responds dynamically to the solar wind drivers and how the response to the external drivers is modulated by internal processes. Specific questions that will be addressed are: (1) what is the relationship between EMIC (electromagnetic ion-cyclotron)waves and the loss of ring current ions via particle precipitation, (2) what are the roles of radial transport, wave-particle interactions, and induced electric fields on the variations in relativistic electron fluxes in the radiation belt during different phases of geomagnetic storms, and (3) what determines the sometimes partial, sometimes complete filling of the slot region between the inner and outer radiation belts.
Understanding the interactions between the solar wind drivers, the ring current and the radiation belts has important impacts on our understanding of space weather, including radiation hazards to space-based technological systems and geomagnetic effects on the ground.
A fundamental problem in space research is the identification of physical processes involved in energizing charged particles. This project conducts research aiming at this goal. Specifically, the research is to identify the energization process for relativistic electrons in the outer radiation belt. The source strength for these relativistic electrons at the outer boundary of the radiation belt is examined with the results that it can be strong enough to provide the seed for these electrons inside the radiation belt. This work is based on multiple measurements from NASA missions called THEMIS (Time History of Events and Macroscale Interactions during Substorms) and Van Allen Probes. Measurements from THEMIS are used to monitor the external source strength for energetic electrons while simultaneous measurements from Van Allen Probes are used to determine the intensity of relativstic electrons inside the radiation belt. This effort of simultaneous comparison has not been done before due to lack of suitable satellite missions that monitor both regions simultaneously. In addition, two external processes at the outer boundary of the radiation belt are identified using measurements from THEMIS. The results from this research may benefit other branches of science that encompass particle acceleration, e.g., space weather, solar physics, and laboratory research involving particle acceleration.
