Charging Potentials for Two Sample Sets of Spectra from DMSP Satellites

Abstract : The importance has been discussed of accurately including the emission of secondary and backscattered electrons in the calculations of flux balances that are used to predict the equilibrium potential of satellites during intense electron precipitation. This concept is applied to a sequence of electron and ion flux spectra observed by DMSP satellites to determine the levels of negative charging, if any, experienced by the satellites. The net electron current incident minus backscattered and secondary electrons is a diagnostic quantity that can be used to determine whether charging has occurred. Using simple models of the satellite and ion collection, along with secondary and backscatter yields for the appropriate covering, one can quickly scan large amounts of data for charging events and estimate the equilibrium potential.