Auroral Precipitation Model and its applications to ionospheric and magnetospheric studies

Based on statistical treatment of DMSP F6 and F7 spacecraft observations, an interactive Auroral Precipitation Model (APM) parameterized by magnetic activity has been created (available at http://apm.pgia.ru/). For a given level of magnetic activity the model yields a global distribution of electron precipitation and planetary patterns of both average electron energy and electron energy flux in different precipitation zones. Outputs of the model were used to determine the basic variables of the magnetosphere, such as boundary location and the area of the polar cap, magnetic flux transferred from the dayside magnetosphere into the tail, global precipitation power realized by different types of precipitation and others. The model predicts an increase in the polar cap area from about 6.3×106 km2 to 2.0×107 km2, in the magnetic flux from 390 MWb to 1200 MWb, and in the global precipitation power from 3.4 GW to 188.0 GW, when the magnetic activity changes from silence (null AL and Dst) to significant disturbance (AL=−1000 nT, Dst=−200 nT). The use of dayside auroral observations as an input for APM provides an opportunity for continuous monitoring of magnetospheric conditions. Two time intervals on Dec. 27, 2000, and Dec. 12, 2004, of dayside auroral observations with the meridian scanning photometer at Barentsburg (Spitsbergen) were selected to demonstrate derivation of magnetospheric variables with APM. It is shown that the values of the AL index derived from optical observation appear in a reasonable agreement with those published by WDC.