Determination of plasma impedance of microwave plasma system by electric field simulation

A simple method has been proposed to determine the plasma impedance based on the electric field simulation of the whole microwave plasma system including the matching network. The plasma impedance can be determined by the experimental parameters in the matching network (positions of the three stub tuner). From the real part of the plasma impedance, the conductivity of the plasma can be deduced. When a reasonable model is assumed to relate the plasma conductivity and the electron density (n(e)), the average n(e) independent of any plasma condition may be obtained. To show the possible procedure to extract the information on the average ne, the present method has been applied for the high-pressure hydrogen plasma generated between a narrow gap (<0.5 mm) where the usual Langmuir probe method is not applicable. The obtained average n(e) is on the order of 10 12 cm(-3), which is consistent with the available experimental results. The present attempt to extract information on the plasma impedance and ne based on the positions of the three stub tuner may be potentially useful in the control of industrial plasma processes. Published by AIP Publishing.