GEC Student Excellence Award Finalist Presentation - Unified Monte Carlo formulation of nanosecond discharges

Nanosecond discharges (ND) exhibit unique characteristics such as high reduced electric fields (E/N~1000 Td) and short timescales, posing significant challenges for accurate modelling. Conventional plasma chemistry models rely on the two-term approximation to solve the electron Boltzmann equation, which proves inadequate for high E/N conditions due to the increased anisotropies in the electron velocity distribution. Additionally, coupling between the temporal evolution of the electron kinetics and the gas-phase chemistry is often addressed using either the local-field or local-energy approximations (LFA or LEA). However, these time-locality assumptions may fall short in capturing the dynamics of ND, where the electron energy relaxation time becomes comparable to the rising time of the electric-field pulse. In this study, we assess the validity of these approximations (two-term and LFA or LEA) by comparing them against the results obtained from a unified Monte Carlo formulation. This formulation stochastically solves the temporal evolution of electron kinetics while continuously advancing the gas-phase chemistry on the electron timescale. Notably, we emphasize the significance of considering properly the mutual influence between excited-state chemistry and electron kinetics - an inherent aspect of this unified formulation.