Emission studies were performed of the flow in front of a blunt body in the various facilities. Shown are graphs of the recorded emission signals. Note that the signals should be treated as qualitative only. The emission in X1 at 14 MJ/kg is approximately three orders of magnitude greater than the Drummond tube emission. Likewise the emission for the 93 MJ/kg condition in X1 is about 50 time more intense than the low enthalpy X1 condition. The graphs show emission over a wide wavelength range and over a more restricted range.
The spectral lines prominent in the spectra are due almost entirely due to flow contaminants. For X1 at 14 MJ/kg, the major contributors are iron, calcium and sodium. At the high enthalpy condition, spectral lines due to calcium, silicon and hydrogen were observed. The Stark-broadened hydrogen lines have also been used for for measuring electron concentrations.