Asymmetrical Triple Probe Method for Determining Energy Distribution of Electron in Plasma

Abstract

A new probe method is proposed. This method is an improvement of the floating triple probe method, which was proposed by us in a previous paper. In this method, the dimension of one operating probe is different from the other, so that the smaller probe behaves as the single probe. Thus, the measurable range of electron energy can be extended as much as that in the single probe method. The asymmetrical triple probe and double probe methods are verified experimentally. The asymmetrical triple probe method has a merit that a disturbance, which is inevitable in the single probe method, can be eliminated in this method. The electron energy distribution obtained by the new probe method is not always in accord with that obtained by the usual single probe method. The hump often observed at high energy range in the single probe method does not appear in the new method, illustrating that the latter is free from erroneous estimation due to the disturbance.