Determination of arc plasma parameters of the AEDC HEAT H1 arc heater using optical emission spectroscopy

Summary form only given, as follows. Time-resolved spectral radiance emission measurements of the arc in the AEDC HEAT H1 Facility were successfully performed during the months of April and May 1991. The H1 Arc Heater is a segmented, vortex-stabilized arc heater used for materials testing under high enthalpy and pressure regimes. Emission spectra of the arc were acquired during a series of 15 HEAT H1 technology tests. Data were acquired for steady-state arc currents of 700 to 1200 A at neutral pressures of 40 to 120 atmospheres. Analysis of the spectra has revealed a number of atomic emission lines of argon, nitrogen, and oxygen on top of a continuum emission. The temporal increase of the plasma density, obtained from Stark broadening measurements, and the evolution of the electron temperature determined by comparing measured line intensity ratios to collisional-radiative model calculations have been investigated.