Direct Display System of Plasma Parameters by Means of a “Non-Floating” Triple-Probe
Sin-Li Chen · Kakuyūgō kenkyū · 1965
The instantaneous direct display system of plasma parameters by means of Triple-Probe cited before, (2) naeds one of the three probes, say probe 2, always be forced at the floating potential in order to obtain the condition I2=O. (I2 : the current flowing into the probe 2). And so, for measurement of voltage difference Vd2, an unit with the impedance Z (or resistance Rfor statlionary cases) = ∞ is required, otherwise the condition of I2=O will be violated. In reality, however, this condition mentioned above is rather difficult to be realized technically, and a small current may be flowing into the probe 2 which should be floated, thus may give rise to some errors in the results of the measurement made. In this paper, the case of the Direct Display System utilizing a “Non-Floating”, triple probe has been discussed, and the probe current as well as the voltage difference between the probes, which will bemeasured for determination of electron temperature Te and electron density Ne are calculated as the function of R, for stationary cases. So that, it is possible to dete-mine Te and Ne even when R≠∞.The percentage errors of Te and Ne measured by means of the usual direct display system, in which the condition R≠∞ is assumed, are also discussed for various kinds of plasmas to be measured, under changing of R.