SOLAR-WIND CONTROL OF DENSITY AND TEMPERATURE IN THE NEAR-EARTH PLASMA SHEET - WIND GEOTAIL COLLABORATION/

A statistical survey of GEOTAIL observations reveals the following. pr operties of the near-Earth plasma sheet (-15 < X-GSM' < -50 Re): Durin g the periods when the northward IMF dominates, (1) the plasma sheet b ecomes significantly cold and dense, (2) the best correlations between the plasma, sheet and the IMF parameters occur when the latter quanti ties are averaged over 9(-4)(+3) hours prior to the plasma sheet obser vations, and (3) temperatures diminish and densities increase near the dawn and dusk flanks of the plasma sheet. We suggest that during prol onged northward IMF periods (similar to several hours) there is a slow diffusive transport of the plasma from the solar wind into the plasma , sheet through the the magnetotail flanks.