Measuring Method for Mach Number in Tokamak Edge Plasma Using Probes

A method for measuring the Mach number in tokamak edge plasmas using electric probes is developed. The Mach number is deduced from the ratio of saturation currents of a Mach probe by taking the ratio of the ion temperature to the electron temperature into account. The present method of considering the effect of the finite ion temperature is applied to the edge plasma in the JFT-2M tokamak.