Investigations on enhanced plasma expansion in pseudospark discharge assisted by a magnetic switch

Abstract

Electrode erosion caused by dense plasma in constrictive discharge channel is one of the fundamentally detrimental effects existing in pulsed discharge switches. An enhanced plasma expansion in pseudospark discharge assisted by a magnetic switch is observed from ICCD images in this paper, accompanied by reduced commutation loss, and the mechanisms are revealed by experiments and simulations. The characteristics of the discharge waveforms and channel images of the pseudospark discharge with and without a series-connected magnetic switch are compared, and the influence of the number of magnetic cores is studied. As the loop current increases, the discharge channel expands radically and reaches the maximum as the current rising rate reaches the maximum. As the number of magnetic cores increases from 0 to 8, the maximum diameter of the discharge channel increases from 16 mm to about 38 mm, and the commutation loss is reduced from 30 mJ to 11 mJ. The electrode erosion rate of the case with a magnetic switch is lower than that without a magnetic switch. A Particle in Cell/Monte Carlo Collision model coupling to nonlinear external circuit elements is established. The simulation results fit well with the experiment phenomena, including the discharge waveforms and the profiles of the discharge channel. The distribution of ions shows more diffused features than that of electrons, while the distribution of electrons is more similar to the discharge channel observed in experiments. The enhanced plasma expansion is mainly caused by the higher radial acceleration component of the charged particles during the magnetically delayed time.

Electron and ion emission characteristics of metal irradiated by nanosecond laser

“…To reduce the influence of impurities on the target surface on the measurement stability, a pre-process procedure is carried out during the experiments, including the electrode polishing, cleaning, drying and vacuum degassing, as described in detail in previous work [25]. Meanwhile, the metal vapor will adhere to the Faraday cup, which has a significant impact on the measurement results.…”