Pseudospark discharge is a special low pressure discharge and has been widely used in the gas switch and electron beam sources. From experiments, when the work pressure is relatively low, the electron beam current or loop current generated by a pseudospark discharge usually has two or more peaks, which has not been fully explained. In this paper, a single-gap pseudospark discharge model is established using 2D kinetic plasma simulation code VSim to study this phenomenon. According to the simulation results, when the anode voltage is 20 kV and the helium pressure is 100 Pa, the current has two peaks, which is similar to the experimental results, accompanied by the stepwise penetration of the virtual anode. This is mainly related to the formation and disappearance of the potential barrier in the cathode hole region. The formation of the potential barrier is caused by the consumption of ions at the cathode hole, and the disappearance is caused by the increase in electrons in the cathode cavity. By classifying the electrons, it is found that the increased electrons are generated by secondary emission caused by ion bombardment on the wall of the cathode. The simulation results also show that the stepwise penetration of the virtual anode can be suppressed or eliminated by increasing the working gas pressure, the secondary electron yield of the cathode material, or the trigger intensity.

The conduction loss of the pseudospark switch (PSS) can be reduced by connecting the magnetic switch (MS) and PSS in series to form the magnetically delayed pseudospark switch (MDPSS). In this paper, a 2D electrostatic Particle in Cell/Monte Carlo Collision simulation model of MDPSS coupled with the external circuit is established, and the discharge process and characteristics are studied. It is found that the forward conduction process of the MDPSS can be divided into four stages. The first stage is characterized by the rapid drop of anode voltage, and the discharge mechanism is mainly the collision ionization of seed electrons. In the second stage, the anode voltage increases slowly, which is mainly maintained by secondary electrons emitted by ions impacting the cathode. The third stage marks the beginning of MS saturation, accompanied by the rapid rise of anode voltage and loop current, as well as the rapid strengthening of the sheath electric field in the cavity, thus inducing the fourth stage, that is, the complete conduction of PSS. The duration of hollow cathode discharge will be prolonged by increasing the number of magnetic cores, thus further reducing the total conduction loss of the switch.

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