Laboratory studies of field-aligned density striations and their relationship to auroral processes
- University of California, Los Angeles, Los Angeles, California 90095-1696 (United States)
Magnetic field-aligned structures in current, density, and temperature are common features of the auroral ionospheric plasma. These structures both generate and transform low frequency waves in the plasma. The results of laboratory studies of two processes involving magnetic field-aligned density depletions (striations) that play a role in auroral plasma dynamics are presented. The first process involves the spontaneous generation of density and magnetic fluctuations at the striation edge. The nature of the fluctuations depends upon the electron plasma beta. At high beta (greater than the electron to ion mass ratio, m/M) the drift Alfven wave is excited. At lower beta the density and magnetic field fluctuations separate and the shear Alfven wave dominates. This process creates an environment conducive to electron acceleration along the magnetic field when the striation size is on the order of the electron skin depth because the shear Alfven wave then has a substantial field-aligned electric field. The second process is the direct conversion of electromagnetic whistler waves to electrostatic lower hybrid waves at the striation edge. This process provides a mechanism for concentrating lower hybrid wave energy in the vicinity of striations where it may play a role in electron and ion heating. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 560643
- Report Number(s):
- CONF-961102-; ISSN 1070-664X; TRN: 9708M0177
- Journal Information:
- Physics of Plasmas, Vol. 4, Issue 5; Conference: Meeting of the Division of Plasma Physics of the American Physical Society, Denver, CO (United States), 11-15 Nov 1996; Other Information: PBD: May 1997
- Country of Publication:
- United States
- Language:
- English
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