Electrode Cooling and Microwave Absorption by Phase Change Fluid Discharge Plasma

Abstract

It is hard to realize the high microwave absorption property and the low operating temperature in a gas discharge plasma simultaneously, due to the electron number density, and electron neutral collision frequency physically needed for the former is a typical severe heating scenario for the latter. In this article, the phase change process is proposed to be introduced into the controlled area of the discharge plasma system to increase collision frequency and decrease the discharging electrode temperature at the same time. An ac high-voltage power-driven quasi-periodic array of the phase change fluid discharge (PCFD) device is investigated. The most apparent tendency of the PCFD plasma is the improved diffusivity and uniformity. At the same time, the temperature of the electrode and its vicinity, where the phase change material is reserved, is lower than the ambient temperature. Compared with the controlled discharge state of the low gaseous pressure dielectric barrier discharge (L-DBD) plasma without phase change process, the absorption attenuation in the <inline-formula> <tex-math notation="LaTeX">$X$ </tex-math></inline-formula>-band is enhanced in all tested polarization angles, which driving strategy could control. Analyses show that the increased microwave absorption, frequency shift, and bandwidth broadening mainly result from the phase change process and its influences on the plasma discharge.