A Dynamic Model for the Auroral Field Line Plasma in the Presence of Field-Aligned Current.
Abstract
We have developed a dynamic numerical model of the plasma along an auroral field line in order to provide a vehicle for studying ionosphere-magnetosphere coupling processes. The model is a multi-moment multi-fluid approximation of a gyrotropic plasma consisting of three species (electrons, hydrogen ions, oxygen ions) along a segment of auroral magnetic field line extending from an altitude of 800 km to 18 earth radii. We have performed preliminary simulations for the case of a current-free polar wind equilibrium of the field line plasma and the case in which a large upward field-aligned current is applied to the field line. In the former case, the agreement between our model and previous static results is reasonable given the differing boundary conditions inherent in the two cases. In the case of field-aligned current, we note that the flux tube plasma responds to the current on several time scales. After an initial rapid response due to electron-ion Joule heating, thermal oscillations of the flux tube plasma persist on time scales of the order of one hour, illustrating the complicated nature of the response of a collisionless plasma when heat flow transport is treated in a dynamic manner. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 23, 1982
- Accession Number
- ADA118298
Entities
People
- H. G. Mitchell Jr.
- P. J. Palmadesso
Organizations
- United States Naval Research Laboratory