Nonthermal Impurity Radiation from a Spherical Plasma

The steady-state energy loss of a homogeneous and isothermal spherical plasma due to de-excitation radiation of impurity ions, assumed to have two energy levels only, is investigated without making the assumption that this radiation is thermal. A method developed by R. N. Thomas is adopted which consists in solving simultaneously the equation of radiative transfer and the equations for the rate of change of the occupation numbers of the energy levels. Analytical methods for calculating the source function obtained in this way are indicated.