Double probe characteristics of a non-Maxwellian plasma

The validity of the floating double probe method is investigated theoretically for plasmas of non-Maxwellian electron energy distribution function (EEDF) using the bi-Maxwellian distribution. A numerical procedure for depicting a double probe curve from single probe curves is presented and the electron temperature diagnostic is examined based on the equivalent resistance method. It is pointed out that there is a possibility of offering misleading results for the electron temperature when using the double probe method to non-Maxwellian EEDF plasmas, depending on the shape of the EEDF and the plasma parameters.