Determining vacuum-arc thruster performance using a cathode-spot model
Journal of Propulsion and Power
Department of Mechanical and Mechatronic Engineering, University of Stellenbosch, Western Cape, Stellenbosch 7602, South Africa; Department of Electrical and Electronic Engineering, University of Stellenbosch, Western Cape, Stellenbosch 7602, South Africa
A simple model of the vacuum-arc cathode-spot and plasma region was developed to predict the performance of vacuum-arc thrusters operating roughly in the arc current range 80-300 A with thrust pulses ≥ 250 μs. The conventional-based cathode-spot model predicts ion current, average ion velocity, and erosion rate to establish thruster performance. Vacuum-arc properties for a range of materials (Al, Ti, Cr, Fe, Ni, Cu, Ag, Pb, Bi) were determined as well as maximum arc spot currents for Ti, Cr, Fe, Ni, and Bi. Model results generally show good agreement with published data and predicted thruster performance is comparable to literature. Most values of ion-to-arc current ratio were within 10% of published experimental data, ion velocities within about 30%, and erosion rates were within roughly 50%, provided macroparticle ejection was low. The crucial role of the ion-to-arc current ratio on thruster performance is assessed. © 2010 by the American Institute of Aeronautics and Astronautics, Inc.
Arc cathode; Arc current; Arc properties; Erosion rates; Experimental data; Ion currents; Ion velocity; Macroparticle; Model results; Plasma region; Simple model; Thruster performance; Chromium; Lead; Soil mechanics; Vacuum; Vacuum applications; Ions