Numerical Simulation of the Gas Discharge in a Gas Peaking Switch

The gas discharge in a gas peaking switch was divided into three phases as gas breakdown, voltage collapse, and gaseous recovery. The development of the discharge was numerically simulated. Nitrogen and hydrogen at pressure ranging from 30 to 100 atm were chosen as working gases. The breakdown field of nitrogen is much higher than that of hydrogen, and a value of 4 MV/cm is achieved for a 0.6-mm nitrogen gap at the pressure of 100 atm. Depending strongly on the breakdown field, the rise time of the output pulse from the nitrogen gap is much shorter than that from the hydrogen gap. The shortest rise time of 108 ps for 0.6-mm nitrogen gap at the pressure of 100 atm is obtained. The gaseous recovery of the extinguished spark channel depends mainly on the recovery of gas density resulting from the falling of the channel temperature due to the axial heat flow out from the channel through the metal electrodes. Hydrogen is much better than nitrogen for gaseous recovery. Electrode material also plays an important role.