Electromagnetic Wave Propagation in a DC Grid Anode Discharge Helium Plasma

Abstract

In the past few decades, the researches on propagation of electromagnetic waves in plasma attract more attention because of its potential applications in communication, aerospace, industry and laboratory research. In order to further study the propagation characteristics of electromagnetic waves in plasma, a tablet-like plasma device is designed, which is generated by a DC grid anode discharge based on the electron beam principle in helium. The electric discharge principle is analyzed, and the discharge characteristics of the plasma device is studied using COMSOL multiphysics. The relationships of discharging characteristics with structure parameters of the device such as electrode gap, and voltage are analyzed. The distribution of electron density is simulated and the collision frequency is calculated. Based on the simulated and calculated results of parameters, the reflection characteristics of electromagnetic wave propagation in this plasma structure have been calculated with the Finite-Difference Time-Domain (FDTD) Method. The influence of electron density distribution, collision frequency and the plasma thickness on the reflection coefficient of incidental electromagnetic wave is analyzed in detail. Then the preliminary propagation characteristics of electromagnetic waves in this plasma has been obtained, and key parameters which affect the electromagnetic wave propagation and the influence are given. These results may provide a better basis of the development of applications such as communication blackout during re-entry, plasma stealth and other related applications.