Extraction of electron plasma energy distribution function using distortion meters

Department of Physics, College of Science, Mosul University, Iraq

Corresponding author: aasimazooz@yahoo.com

Received: 30 May 2005
Revised: 21 February 2006
Accepted: 28 February 2006
Published online: 4 May 2006

Abstract

A new method for direct evaluation of the electron energy distribution function in plasmas is suggested, which involves the use of audio frequencies distortion factor meters. The amount of distortion suffered by a Langmuir probe AC current produced by superimposing a clean AC voltage on the DC probe voltage is measured. Although such distortions are proportional to the second derivative of the probe characteristic at any point when its neighborhood can be approximated by a second-degree polynomial, the instrument function is always sharper than that of harmonic differentiation. The method is analyzed theoretically, and tested experimentally. It is also shown that distortion additionally provides a direct measure of the electron temperature.