Radiation Emission Coefficients for Modeling Finite High-Pressure Thermal Plasmas

A new approach is presented for handling the radiative transfer in high-pressure plasmas where collision broadening dominates the self-absorption spectra. The net radiation leaving a plasma finite-volume element is treated as the difference of two terms: a local net emission term less a second term which represents the absorption from the rest of the discharge medium, a global absorption term. The latter is particularly convenient for calculating collision-broadened spectra, which normally dominate high-pressure thermal plasmas. This approach can be extended readily to the electrode termination regions of thermal plasmas and to practical arcs of finite dimensions.