A calculation of the intensities of optically thick lines emitted by hydrogen-like ions in a steady-state plasma

The intensities of optically thick lines emitted by hydrogen-like ions in a plasma which is in a steady state have been calculated for electron temperatures between 8000 Z 2 °K and 256 000 Z 2 °K and for electron densities between 10 8 Z 7 cm -3 and 10 18 Z 7 cm -3 , where Z is the charge of the bare nucleus. The optical thickness of the plasma, which is conveniently measured at the centre of the Lyman α line, is between 0.1 and 100 for a uniform plane parallel plasma. The calculations solve the coupled equations of transfer when necessary for the first twenty levels for the absorption and stimulated emission of photons in the lines and include the processes of excitation, de-excitation and ionization by electron collision, spontaneous radiative decay, three-body recombination and radiative recombination. It is assumed that the ratio of the electron density to the bare ion density is constant through the plasma. It is also assumed that all the lines are Doppler broadened and that the plasma is optically thin for the continuum. Tables give the total intensity of the Lyman α and β lines and the Balmer α and β lines, the total power radiated in the lines from both sides of the plasma and the geometrical size of the plasma. The population density of the ground level is given when this is not very small compared with the electron density.