Energetics of the Plasma Sheet

点击翻译按钮获取中文摘要

This research project involves a study of the energetics and thermodynamics of the Earth's plasma sheet. The methods to be used were developed with support from a prior NSF grant. Geotail satellite data is used to generate a series of long term averaged three-dimensional models of the plasma sheet. Each model in a series is produced using only data corresponding to a specific geophysical condition. The models can represent the plasma sheet under selected solar wind and interplanetary magnetic field conditions, in regions characterized by selected flow velocities, near magnetic reconnection regions, during selected substorm phases, etc. Each data based model includes 3-D information about both the magnetic field and about each of several hundred ion and electron plasma parameters. The new particle and field parameters the electron and ion heat fluxes, Boltzmann entropies, and partial densities associated with twelve energy bands. Heat fluxes have not previously been included in 3-D data based models of the plasma sheet. They play an important role in the generation of the field aligned currents and the flow of energy between the plasma sheet and the ionosphere. The Boltzmann entropy is a new parameter that will be compared to the entropy parameters investigated in our earlier studies. Differences between the entropy parameters are caused by non-Maxwellian features of the distribution functions and by the loss of particles from flux tubes. Models of the measured plasma and field parameters can be used, among other things, to study plasma instabilities, to compare with global magnetospheric simulations, and as a test of global environmental and space weather model predictions. Space weather and environmental modeling programs are expected to have an important impact on communications issues that will be of interest to a much broader population. The availability of 3-D data based models is potentially useful in the planning of future satellite missions.