Transmission characteristics of microwave in a glow-discharge dusty plasma

In this study, the propagation characteristics of electromagnetic wave in a glow discharge plasma with dust particles are experimentally investigated. A helium alternating current glow discharge plasmas have been successfully generated. Measurements of the plasma parameters using Langmuir probes, in the absence of dust particles, provide plasma densities (n_e) of 10¹⁷m^-3 and electron temperatures (T_e) ranging from 2 to 4 eV. Dusty plasmas are made by adding 30 nm radius aluminum oxide (Al₂O₃) particles into the helium plasma. The density of the dust particle (n_d) in the device is about 10¹¹-10¹²m^-3. The propagation characteristics of electromagnetic waves are determined by a vector network analyzer with 4-6 GHz antennas. An apparent attenuation by the dust is observed, and the measured attenuation data are approximately in accordance with the theoretical calculations. The effects of gas pressure and input power on the propagation are also investigated. Results show that the transmission attenuation increases with the gas pressure and input power, the charged dust particles play a significant role in the microwave attenuation.