Simultaneous Observations of Neutral Winds and Electric Fields at Spaced Locations in the Dawn Auroral Oval.

摘要

On March 21, 1987, a chemical release experiment was carried out in the dawn sector of the auroral oval and polar cap to measure E and F region neutral winds. The Sondre Stromfjord, Greenland, incoherent scatter radar provide electric field and electron density measurements for 14 hours prior to the experiment and 6 hours after. F region wind measurements were available throughout the night of March 20-21. The 30-hour period prior to the launch was quiet, except for minor substorms, and the y component of the IMF was away from the Sun corresponding to positive By. The results show that F region neutral flow was in the direction expected with a By > 0 plasma convection pattern if the Lorentz forcing was dominant. The gradients in the flow were found to have comparable contributions from the divergence and vorticity. The E region winds showed a complicated spiral structure in which the tip of the wind vector traced out an anticyclonic spiral with increasing height. However, the direction of rotation reversed over a small height range near 110-km altitude. Reprints. (jhd)