Investigations of Microwave Switching in Gas Discharge Tube With Two-Electrode Spark Plasma Ignition

In this article, a 3-D self-consistent microwave plasma coupled fluid model is employed to simulate the microwave switch. Numerical simulations were performed with different electrode distances to investigate the characteristics of spark discharge plasma switching under varying conditions. The evolution process within the plasma switch can be divided into two stages: the spark discharge stage and the microwave heating stage. During the spark discharge stage, initial plasma is generated, which concentrates the radio frequency (RF) electric field at the upper and lower ends of the plasma region. The plasma then expands under microwave heating until it reflects the electromagnetic wave outside the gas discharge tube (GDT) due to the skin effect. The simulation results demonstrate that the plasma switch with a large electrode distance has a faster corresponding speed and a reflection coefficient that can reach −1 dB, and a comparison with experimental data is presented, which demonstrates good quantitative and qualitative agreement. This study can provide guidance for the design of microwave plasma switches.