New Method for the Determination of the Electron Temperature from Langmuir Probe Characteristics

The electron retarding current collected by a Langmuir probe in a plasma possessing a Maxwellian electron energy distribution function is a an exponential function. If such a current is smoothed by a non-recursive filter the result is a product of the original current and a factor independent on probe voltage. This leads to a shift between the floating potentials of smoothed and unsmoothed probe current from which the electron temperature V(e) may be obtained. A suitable smoothing filter is chosen and all means necessary for the practical realization of the method are given. The influence of the ion current on the determined value of Ve is investigated. The convenience of the method is shown by means of testing calculations and a measuring example. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim