The Significance of Accurate Needle Electrode Geometry Definitions in Discharge Plasma Finite-Element Simulations: A Comparative Analysis

This paper aims to explore the significance of accurately defining the geometry of needle electrodes in gas discharge plasma finite-element simulations and evaluate the sensitivity and responsiveness of simulation outputs to different needle electrode shapes. Using a hydrodynamic (drift-diffusion) model and COMSOL Multiphysics software, a comprehensive numerical analysis is performed to investigate the influence of six needle geometries (hyperbolic, elliptic, and circle-with-tangents) with an equal radius of curvature on negative air discharge plasma characteristics. The study aims to establish a comparative understanding of how the defined geometries relate to the behavior of the discharge plasma. Various aspects, including the properties of Trichel pulses, the spatiotemporal evolution of charged species, and the electrical field distribution, are explored.