Accession Number : ADA330615

Title :   Cascade Arc Studies of Nonequilibrium Hydrogen/Nitrogen Plasma Propellants.

Descriptive Note : Final rept. 15 Sep 95-14 Sep 97,

Corporate Author : TENNESSEE UNIV SPACE INST TULLAHOMA

Personal Author(s) : Keefer, Dennis R.

PDF Url : ADA330615

Report Date : 12 SEP 1997

Pagination or Media Count : 56

Abstract : A cascade arc facility was developed to study the characteristics of nonequilibrium plasma propellants for electric propulsion applications. The cascade arc was operated with hydrogen arcs at 2.0 and 6.0 psi. Spatially resolved spectral emission data were collected using a two dimensional Optical Multichannel Analyzer (OMA). Electron density was determined by fitting theoretical line profiles to experimentally measured Abel inverted emission line profiles. Radial distributions of plasma temperature also were estimated from Boltzmann plots of spectral line intensity. The measured electron number densities and plasma temperatures were compared to values predicted by nonequilibrium cascade arc simulations using the UTSI Cascade Arc Plasma Simulation (CAPS) code. The simulations underpredicted the peak experimental number densities by as much as an order of magnitude and over predicted peak plasma temperatures by as much as a factor of 2.5. The experimental electric field has been accurately predicted by varying chemical kinetics in the CAPS code. Kinetic models developed at the University of Illinois were found to give the best agreement with the Cascade Arc measurements. Electron number density profiles for simulated ammonia and hydrazine were also obtained at pressures of 2, 6 and 10 psi. Kinetic models for these mixtures will be evaluated when the CAPS code has been modified to simulate these propellants.

Descriptors :   *PLASMAS(PHYSICS), *NITROGEN, *HYDROGEN, COMPUTERIZED SIMULATION, REACTION KINETICS, EMISSION SPECTRA, NONEQUILIBRIUM FLOW, STARK EFFECT, BOLTZMANN EQUATION, ELECTRIC PROPULSION, SPECTRAL LINES.

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE