Space Weather: Determining Electric Fields through Inversion of Charged Particle Drift Measurements from a Finite Number of Spacecraft

Southwest Research Institute, San Antonio TX

Investigators

Abstract

The existence, structure and dynamics of magnetic and electric fields in the inner magnetosphere define the movement of charged particles throughout that region. Knowledge of these fields is necessary to understand the particle dynamics, regardless of the level of geomagnetic activity. In the area of magnetic fields, there are good models which allow the field to be quickly and easily calculated for a variety of different conditions. This cannot be said for the electric fields in the magnetosphere. The biggest untapped resource, which can help us improve our knowledge and description of magnetospheric electric fields is that of numerous in-situ plasma particle measurements. This project will develop an inversion technique which combines the use of in situ plasma particle measurements with the framework of the UBK theory. The inversion technique will use charged particle measurements and the UBK theory to calculate electric fields even in the absence of direct electric field measurements. The project will also investigate what fleet of satellites would be necessary to invert the electric field for a known magnetic field configuration. This will include specifying fields in the inner magnetosphere as a whole, or in sub-regions of it (e.g. the tail only, dayside only etc.). This will determine what results could be expected from existing constellations of spacecraft (GPS, LANL, Geo, GOES, Cluster, POLAR, GEOTAIL, all of which are operational at the same time). The research will be embedded into an outreach program specifically designed to high school and college students.