Non-invasive impedance measurements of electron density and temperature and implications for complex dusty plasmas*

A non-invasive method of probing the complex impedance of a plasma discharge has been developed where a discharge electrode is used to sustain the discharge as well as measure the discharge impedance. This diagnostic models the discharge as a collection of circuit elements and measures the resonant frequencies of the discharge. The resonant frequencies elucidate several discharge characteristics that in turn are used to calculate electron density and temperature. More refined analysis techniques and further experimental measurements have been performed in both non-dusty and dusty discharges. Comparisons between this impedance diagnostic method and Langmuir probe measurements will be discussed, as well as implications and advantages of this probing technique for use in dusty plasma applications.