Probe measurements in a plasma having an anisotropic electron velocity distribution function

In this paper a number of questions connected with the diagnostics of anisotropic electron velocity distribution functions possessing a drift velocity were examined. In an example involving a model distribution function, the possible errors in measurements of the electron energy distribution function (EEDF) using a cylindrical probe oriented parallel to the particle flow are estimated. It is shown that application of a standard method for treating probe volt-ampere characteristics leads to over- and underestimates relative to the true values of the measured temperatures T _e ⁺ and T _e ^– , found respectively according to the currents i⁺(V) and i^–(V) on a flat probe, oriented along and against a specific direction. A comparison of calculated T _e ⁺ +/T _e ^– ratios is made with experimental data.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 9–13, September, 1990.