Wing-Slope Techniques for the Analysis of Langmuir-Probe Characteristics in a Low-Density Plasma

Abstract

The volt‐ampere characteristics of Langmuir probes utilized in ionospheric investigations and employing ideal geometries (spherical or cylindrical) contain a considerable amount of information, much of which is not utilized in the usual analysis programs. The slope of the V‐i curve for large accelerating potentials contain a substantial amount of information on mass density and temperature. We have developed equations for the current and its slope in this region for both of the above geometries and have applied them to a few typical situations. We conclude that the usefulness of Langmuir‐probe techniques may be appreciably improved by performing a ``total analysis'' on the available information. In some cases, measuring the slope directly will supply the same information with a substantial saving in experimental complexity.