The Langmuir probe measurement of flow velocity in a flame plasma

Abstract

A method of measuring the flow velocity in a flame or other collision dominated plasma is described. It is based on the velocity characteristic of a Langmuir probe which is swept through the plasma. The probes were operated in the sheath-convection régime and exhibited a systematic variation between thin and thick sheath behavior which was attributed to an expanding sheath as the plasma–probe conditions were varied.