Investigating the Influence of Free-Electron Pulses and Neutral Excited Species Formation on Discharge Development: By PD Quantum Optics Analysis and Plasma Simulation

Abstract

Previous studies on discharge dynamics have primarily focused on the generation and migration of the charged particles and neglecting the influence of neutral excited-state particles. In this study, an integrated approach combining experiment and simulation was used to investigate the effect of neutral excited particles on discharge development. Firstly, partial discharge was induced by applying voltage to a pin-plate electrode in a darkroom environment and the emission spectrum of discharge was captured using an ultra-sensitive spectrometer. Then the formation mechanism of the main neutral excited particles in air corona discharge was analyzed based on the principle of quantum optics, and the collision cross-section data of the non-local thermodynamic equilibrium (NLTE) plasma chemical model for air was updated accordingly. Simulations revealed the process of electron pulses initiates the electron avalanche, which leads to dielectric breakdown. Results indicated that overvoltage can lead to the formation of electron avalanches at defect sites, which is capable of causing dielectric breakdown within the nanosecond time scale. The competitive mechanism of the excitation reactions to ionization reactions results in the dissipation of free electrons' energy, effectively suppressing the development of electron avalanches and preventing electrical breakdown.