AVS 52nd International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS-WeA

Paper PS-WeA8
Modeling of Pulsed Microdischarges for use as Thrusters@footnote 1@

Wednesday, November 2, 2005, 4:20 pm, Room 302

Session: Atmospheric Plasmas and Microdischarges
Presenter: R.A. Arakoni, University of Illinois at Urbana-Champaign
Authors: R.A. Arakoni, University of Illinois at Urbana-Champaign
J.J. Ewing, Ewing Technology Associates
M.J. Kushner, Iowa State University
Correspondent: Click to Email
Microdischarges having characteristic dimensions of 100s of µm with back pressures of 10s to 100s of Torr are being investigated for use as sources of thrust for small satellites. These devices are capable of generating up to mN of thrust using noncontaminating propellants such as rare gases. The class of device of interest is a cylindrical discharge operated in dc or pulsed modes. The bore of the discharge is fabricated in a heat-resistant ceramic with micro-fabricated ring electrodes. The dominant mode of propulsion is thermal heating of the neutral gas by the discharge, primarily by charge exchange. In this talk, this class of microdischarge will be computationally investigated using a 2-dimensional plasma hydrodynamics model having an unstructured mesh to resolve non-equilibrium electron, ion and neutral transport using fluid equations.@footnote 2@ Sheath accelerated, beam-like electrons are resolved using a Monte Carlo simulation. A compressible Navier-Stokes module provides the bulk fluid velocities and temperatures. Changes in surface properties are addressed with a surface site-balance model. Results from a parametric investigation of back pressure (a few 10s to 100s of Torr), power, and pulse length will be discussed for rare gas mixtures with the goal of maximizing the velocity of the exhaust at the exit plane. Velocities of up to 100s m/s have been predicted in the throats of the devices with plasma densities of 10@super 13@ - 10@super 14@ cm@super -3@ with back pressures of 50 Torr in a cw operation mode. Since the source of propulsion is plasma heated gas, the siting of the plasma within the bore of the microdischarge, and subsequent heat transfer to the walls, is an important design consideration. @FootnoteText@ @footnote 1@ Work supported by Ewing Technology Associates, NSF (CTS03-15353) and AFOSR. @footnote 2@ A. N. Bhoj and M. J. Kushner, J. Phys. D, 37, 2910 (2004).