Transmission-Type Impedance Probe Measurements for Dusty Plasmas*

Plasma impedance probes measure electron density and temperature by measuring plasma response to an applied low-power RF signal at frequencies on the order of the electron plasma frequency, ω­_pe. These measurements may be well-suited for use in dusty plasmas because the probes can be designed to be less perturbing to the dust particles than, for example, a Langmuir probe. Double-tipped, transmission-type impedance probes may be especially useful for dusty plasmas because they can be separately sensitive to plasma in areas near the probe tips and areas farther away.

In this poster, we discuss the use and analysis of double-tipped impedance probe diagnostics. We present circuit model simulations of these diagnostics and compare the results to experiments in a capacitively-coupled RF plasma. We further discuss the use of the diagnostic for dusty plasma applications. For example, we discuss a potential method for measuring the charge absorbed by a dust cloud by measuring the cloud’s effect on electron and ion densities in the surrounding plasma.