We used the tone burst floating probe method to measure plasma parameters in a hollow cathode discharge. In this method, the electron temperature is directly calculated from a shift in the floating potential of the burst interval when a tone burst signal is applied to a probe through an intermediary blocking capacitor. The tone burst signal is a signal that applies an ac signal for a fixed time and turns off the remaining time of the cycle. It was possible to measure the same electron temperature as in the floating probe method that we previously reported. In the tone burst floating probe method, it is possible to measure the ion current by a shift in the floating potential from the time constant of the burst interval. This is a new measurement method that can measure the plasma density from the ion current and the electron temperature during the tone burst signal input.

Plasma diagnostics of the electron temperature was performed through a hollow-cathode-type discharge tube using a pulsed and floating probe method. This method detects a shift in the floating potential when a pulse signal is fed into the probe through an intermediary blocking capacitor. The electron temperature was calculated in a previous study using the Bessel function of the nth order; however, the proposed method greatly simplifies the calculation. In the duty ratio between 10% and 30%, the electron temperature measured using the pulsed and floating probe methods was approximately equal to the tail electron temperature, and it was varied by adjusting the duty ratio.

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