Development of a Langmuir probe for plasma diagnostic work in high speed flow

At the present time there is an interest in controlling high-speed flow over a body utilizing a plasma and an applied magnetic field. In order to critically understand what is happening in this process it is necessary to characterize the plasma. This paper outlines the development of a Langmuir probe for this task and presents some data taken in a quiescent plasma. A Langmuir probe can be used to determine the electron number density, the electron temperature, and the electric field as a function of position in the plasma. From this information the electrical conductivity can be determined utilizing drift velocity data available in the literature. Both a single and a double Langmuir probe were developed and tested.