Experimental investigation of the radiation properties of an air plasma in the spectral range 400-1200 nm

The spectral distribution of the emissivity and absorption coefficient of an air plasma at five atmospheres pressure in the wavelength range 400-1200 nm and temperature range 9,000-14,000 K was determined with mean spectral resolution of 2.4 nm. Using measurement results and published data for a plasma at atmospheric pressure, the authors have determined the intensity of radiation of an air plasma layer 1 cm thick integrated over the studied wavelength range, and have distinguished the contribution from the continuum and from atomic spectral lines with allowance for self-absorption. As pressure was increased from 1 to 5 atm in the temperature range studied, the air spectrum suffered no significant changes. The absorption coefficient for the corresponding spectral zones increased by about one order of magnitude.