Solar wind control of density and temperature in the near-Earth plasma sheet: WIND/GEOTAIL collaboration

T. Terasawa, M. Fujimoto, T. Mukai, I. Shinohara, Y. Saito, T. Yamamoto, S. Machida, S. Kokubun, A. J. Lazarus, J. T. Steinberg, and R. P. Lepping

Department of Earth and Planetary Physics, University of Tokyo, Japan


A statistical survey of GEOTAIL observations reveals the following properties of the near-Earth plasma sheet (-15 < XGSM < -50 Re): During the periods when the northward IMF dominates, (1) the plasma sheet becomes significantly cold and dense, (2) the best correlations between the plasma sheet and the IMF parameters occur when the latter quantities are averaged over 9 +3-4 hours prior to the plasma sheet observations, and (3) temperatures diminish and densities increase near the dawn and dusk flanks of the plasma sheet. We suggest that during prolonged northward IMF periods (~ several hours) there is a slow diffusive transport of the plasma from the solar wind into the plasma sheet through the magnetotail flanks.

Geophys. Res. Lett., 24, 935-938, 1997