Influence of pulse width on the breakdown process of nanosecond pulse discharge at low pressure

Abstract

Pulsed plasma discharge breakdown has long been a subject of research in the field of plasma physics. However, the spatial distribution and temporal evolution of parameters such as the density, energy, and electric field of charged particles during the breakdown process have not been thoroughly investigated. In this study, we investigate the breakdown process under nanosecond pulses with different pulse widths (1 ns, 10 ns, and 100 ns), utilizing the 1D implicit particle-in-cell/Monte Carlo collision method. Our simulation results indicate that pulse width plays a crucial role in the evolution of plasma breakdown. Specifically, under ultra-short pulses, the breakdown occurs after the pulse voltage ceases, demonstrating that increasing pulse width accelerates the changes in plasma parameters but does not affect the breakdown time. Under longer pulses, the removal of voltage leads to a significant increase in the thickness of the anode sheath. As the pulse width continues to increase, the ions collide in the cathode sheath after the pulse ends, resulting in ion energy loss. Finally, by scanning the parameter space, we give the Paschen curve and observe a higher breakdown voltage in the pulse case and the impact of ion secondary electrons.