Modification of Probe Characteristics in a Supersonic Plasma Flow

Abstract

The effects of a supersonic plasma flow on emissive Langmuir probes were experimentally investigated using a Pockels electric field sensor. When the flow velocity exceeded the ion sound speed, the probe characteristics were modified, and the emissive probe overestimated the plasma potential. The modification of probe characteristics is explained by the formation of a humped potential profile, caused by a shock in the supersonic plasma flow.