Use of a hybrid code to model the Earth's magnetosphere

Abstract

This paper presents a demonstration of the use of a hybrid code to model the Earth's magnetosphere on a global scale. A hybrid code calculates the interaction of particle ions and a massless electron fluid with the magnetic field. The demonstration is a simulation of the noon meridian plane of the magnetosphere. Innovative features of the code include a numerically generated curvilinear coordinate system, approximation of the cold ionospheric plasma as an MHD fluid that coexists with the kinetic plasma and subcycling of the magnetic field update to the particle push. These innovations allow the code to accommodate disparate time and distance scales. New results include particle acceleration in the cusp and nearly field aligned currents linking the cusp and polar ionosphere. It is pointed out that such a code is needed help resolve many of the outstanding questions regarding substorm dynamics and perhaps form the basis of a numerical space weather prediction scheme.