Modeling of Argon Plasma Excited by Microwave at Atmospheric Pressure in Ridged Waveguide

As a microwave plasma excitation structure, the tapered waveguide is mostly used in some industrial applications. A novel ridged waveguide is proposed in this paper. The fluid approximation method is applied here to simulate the excitation of argon plasma within 1 s at atmospheric pressure. Some physical parameters, such as the electron density, electron temperature, gas temperature, and scattering parameter S
₁₁
, are obtained. When the input power is set to 1500 W, and the steady state is achieved, the electron density reaches 3.05×10
²⁰
m
^-3
, the electron temperature gets to 282 15 K, and the gas temperature is 5590 K. Remarkably, at the same power, the energy coupling efficiency from microwave to plasma is 17.3% higher than that in the tapered waveguide, and the electron density and gas temperature also increase by 4.5 × 10
¹⁹
m
^-3
and 346 K, respectively.