The type and extent of non-LTE in argon arcs at 0.1-10 bar

A 30-A, 3-mm-diameter, wall-stabilized argon arc with 1% hydrogen is examined spectrometrically at pressures of 0.1-10 bar. Values of T_g, and T_exa diverge as pressure decreases below 5 bar (n_e⩽1×10¹⁷ cm^-3) at r=0. T_exβ is 20-40% larger than the other temperatures. The results are dependent on the transition probability scale used     

In-bore spectral measurements in a plasma-armature railgun

Quartz optical fibers have been used to obtain quantitative, time-integrated, high-resolution, in-bore spectra from a plasma-armature railgun. The observed spectrum consists primarily of continuum radiation, and the only significant spectral features are resonant absorption lines. A detailed plasma-radiation model was used to predict the spectrum in the region of the absorption lines, providing an estimate for the concentration of aluminum and copper in the plasma. This model was also used to estimate the temperature profile of the armature. A reasonable agreement between the model and the observed spectrum yielded a concentration of 10% aluminum and 10% copper in the armature, with a centerline plasma temperature of 20000 K