D-region probe theory

Abstract

A systematic theory of a parachute-borne blunt probe operating in an altitude range from 50 to 80 km is presented. The relationships between positive ion, negative ion, and electron densities and the current to the probe and the probe voltage are found. It is shown that order of magnitude errors occur if a free molecular flow theory is used in this altitude range. No direct measurement of negative ion density is available for a probe voltage large compared to kT/e, the case considered. The results are somewhat analogous to Gerdien condenser theory.