Abstract
The earth's auroral zone contains dynamic processes occurring on scales from the length of an auroral zone field line (about 10RE) which characterizes Alfven wave propagation to the scale of microscopic processes which occur over a few Debye lengths (less than 1 km). These processes interact in a time-dependent fashion since the current carried by the Alfven waves can excite microscopic turbulence which can in turn provide dissipation of the Alfven wave energy. This review will first describe the dynamic aspects of auroral current structures with emphasis on consequences for models of microscopic turbulence. In the second part of the paper a number of models of microscopic turbulence will be introduced into a large scale model of Alfven wave propagation to determine the effect of various models on the overall structure of auroral currents. In particular, we will compare the effect of a double layer electric field which scales with the plasma temperature and Debye length with the effect of anomalous resistivity due to electrostatic ion cyclotron turbulence in which the electric field scales with the magnetic field strengtH. It is found that the double layer model is less diffusive than the resistive model leading to the possibility of narrow, intense current structures.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 351-366 |
| Number of pages | 16 |
| Journal | Laser and Particle Beams |
| Volume | 5 |
| Issue number | 2 |
| DOIs | |
| State | Published - May 1987 |
Bibliographical note
Funding Information:The authors would like to thank W. Lotko and D. S. Evans for useful discussions on this work. This work was supported in part by NSF Grants ATM-8451168 and ATM-8508949 and NASA Grant NAGW-809. Computing costs were supported by the University of Minnesota Supercomputer Institute.