Some experiments on probe characteristics in drifting plasma

Abstract

An experimental work is presented to examine the previous analysis by T. Dote et al., for the estimation of positive ion density in the ionosphere from the ion current obtained by a rocket-borne Langmuir probe. The plasma was formed in a low-density supersonic wind tunnel, where the probe characteristics were measured. The drift Mach number, the pressure and the temperature of the plasma were 3, 86 microns Hg and 107°K respectively. It is indicated that the values of positive ion density estimated by the previous analysis are nearly equal to the values of electron density obtained from the electron saturation current characteristics which are considered to be almost independent of the supersonic drifting of plasma.