Radiation transport in wall-stabilised nitrogen arcs

Radiation transport within wall-stabilised nitrogen arcs has been investigated for pressures of 1 and 10 atm. The computations allow for continuum and N I and N II line transport, and some molecular band absorption. The spectral data used gives reasonable agreement with experiment for the radiative balance on the arc axis at 1 atm. The calculated radiative arc loss accounts for a significant fraction of the electric power input, and it is found that losses at wavelengths less than 1000 AA are most important over a wide range of conditions. The dominant contribution to the loss is made by line radiation transport. Experimental temperature profiles were used for the 1 atm calculations, and for 10 atm the profiles were predicted using an approximate value for the local radiative balance determined from isothermal-arc calculations.