Thermal structure of an Alouette 2 topside profile as deduced from rocket measurements

A Javelin rocket with a payload of ionospheric instruments was launched from Wallops Island in conjunction with an overpass of the Alouette 2 and Explorer 31 satellites. The rocket-measured values of ion and electron temperatures, which had large positive gradients with height, were found to be consistent with the measured electron concentration profile, though this same profile was also consistent with an isothermal plasma. A downward heat flux from the magnetosphere of 1.9 × 1010 ev cm−2 sec−1 was deduced, which could be supplied by an upward flux of photoelectrons from the F layer of approximately 1.5 × 109 cm−2 sec−1.