Modeling of Plasma Expansion during Pulsed Electron Beam Ablation of Graphite

Abstract

Pulsed electron beam ablation (PEBA) has proven to be a promising and powerful technique for the growth of high quality thin films. Pulsed electron beam film deposition consists of many physical processes including target material heating, target ablation, plasma plume expansion, and film growth on a substrate. Plasma plume expansion into a vacuum or an ambient gas is a fundamental issue in PEBA as the quality of thin films deposited onto the substrate depends on the composition, energy and density of particles ejected from the target. In the present study, gas-dynamics equations are solved to investigate plasma expansion induced by interaction of a nanosecond electron beam pulse (~100 ns) with a graphite target in an argon atmosphere at reduced pressure. The spatio-temporal profiles of the temperature, pressure, velocity, and density of the plasma plume are numerically simulated for a beam efficiency of 0.6 and accelerating voltage of 15 kV. The preliminary results show a rich variety of behaviors. The model is validated by comparing some of the obtained simulation results with experimental data available in the literature.

Effects of plasma expansion plumes in view of pulses laser irradiating centimeter-scale spherical space debris

“…where T a denotes the initial ambient temperature, P a denotes the initial ambient pressure, n v denotes the vapour density, and v denotes the initial velocity. Further, the debris material is ionized to form a high temperature and high pressure plasma expansion plumes when the pulse laser energy is close to 10 9 kW/cm 2 for the aluminum alloy, and the corresponding expression is given as follows [16]:…”