A One-Dimensional Modeling of Seed Electron Generation and Electron Avalanche in Laser-Supported Detonation

Abstract

A one-dimensional numerical analysis has been conducted to investigate the laser-induced discharge mechanism in the laser-supported detonation. The radiative transfer equations for the laser and ultraviolet lights are coupled with the fluid equations of electrons and heavy particles. Photoionization and electron avalanche are considered in the ionization model. The steady-state problem of ionization wave propagation is computed by using the reference frame fixed to the ionization wave. The electron density distribution and electron temperature distribution are compared between the simulation and experiment. Quantitative agreements are confirmed in the peak electron density and electron temperature with differences of 38% and 24%, respectively. The simulation results indicated the existence of the precursor region, where the seed electrons are generated by the photoionization rather than avalanche ionization. In the condition of argon gas and 10.6 μm laser, the location of precursor region is estimated as 0.03–0.14 mm from the ionization wave front. The ionization wave propagation is governed by the self-consistent discharge mechanism consisting of photoionization, electron avalanche, and ultraviolet light radiation.