Plume Structure and Current-Voltage Characteristic Analysis for a Cathodic Plasma Contactor

In this study, a spherical symmetric theoretical model is chosen to predict the plume structure and the current-voltage of a cathodic plasma contactor. An isothermal model regardless of neutrals is employed to simulate the plume structure in the working condition of high voltage and low current. High electron temperature, placing ionization chamber, large gas flow rate and raising keeper (or anode) current all can improve the current-voltage characteristic. Both models tell that the potential distribution mainly depends on the ratio of potential and temperature while density changes little and the results are approximated to each other. It is calculated that the sheath layer of the vacuum chamber cannot be ignored when the voltage near the chamber is high and density is low based on the classical collisionless sheath model.. Key-word:cathodic plasma contactor, current-voltage characteristic, plume structure, sheath layer