Determining Plasma Potential from RF Measurements Using an Impedance Probe

摘要

We present an rf technique for finding plasma potential for both low and high neutral pressure plasmas in the thin sheath limit. It requires only readily available instrumentation and has the added advantage that the measurement is non-perturbative to the plasma. The technique is based on combined experimental and theoretical methods developed in the Charged Particle Physics Branch at the Naval Research Laboratory. The method has general application to diverse areas of plasma investigations in the laboratory or in space plasma measurement application. It can be used with in situ instrumentation itself and can be extended to provide an estimate of the sheath structure for arbitrarily shaped surfaces. Because the magnitude of the applied signal used is much smaller in magnitude than typical applied dc potentials, it is transparent to the existing plasma/probe interface.