Temperature and ion abundance profiles deduced from simultaneous explorer XXXI and Alouette II data

Field-aligned electron concentration profiles from the Alouette II sounder are combined with simultaneous measurements of ion and electron temperatures and relative ionic abundances measured by the Explorer XXXI satellite at its orbit to deduce plasma ternperature ((Te+Ti)/2) and ion concentration profiles using a diffusive equilibrium theory. Analysis of eleven Alouette II-Explorer XXXI passes during December, 1965, and January, 1966, indicates that regions of constant or slightly decreasing plasma temperature with height are common in the lower exosphere. These results imply the presence of regions of negative or zero ion temperature gradients since experiment and theory generally yield nonnegative electron temperature gradients over the altitude range considered. The possibility of negative ion temperature gradients has been suggested by Banks [1].