The Average Pattern of Auroral Particle Precipitation, Its Associated Conductivity and Field Aligned Currents

Abstract

A series of statistical studies has been completed to determine the global pattern of auroral electron and ion precipitation and their resultant Hall and Pedersen conductivities as a function of geomagnetic activity, solar wind velocity, the orientation of the Interplanetary Magnetic Field (IMF) and season. In addition, studies were performed relating these global patterns in particle precipitation to similar global determinations of the average delta B vector produced by the auroral field aligned currents. The data for these studies were from instruments flown on the satellites of the Defense Meteorological Satellite Program (DMSP). In all cases the studies were performed by dividing the high latitude region into a series of spatial bins in Magnetic Local Time (MLT) and corrected geomagnetic latitude (CGL). One such matrix of spatial bins was created for each different value or range of values of chosen sort parameter. For geomagnetic activity the sort parameter was one of seven levels of Kp. For the IMF and solar wind velocity the sort parameters consisted of 30 paired ranges of the solar wind velocity and the Bz component of the IMF. A rough separation by the IMF By was performed by using the IMF sector structure and Kp together as the sort parameter. Seasonal separations were made with Kp and for time periods centered on the summer and winter solstices and the equinoxes. In all cases the large DMSP data sets were used to determine the average spectrum of precipitating electrons and ions and the average delta B vector for each spatial bin and for each sort parameter used. In this paper we review the results of these studies.