Abstract
The instantaneous population densities for the excited levels of hydrogen-like ions in an optically thin plasma, which is not necessarily in equilibrium, have been calculated for a range of electron temperature of 4000Z2 °K to 256 000Z2 °K and electron density of 108Z7 cm-3 to 1018Z7 cm-3, where Z is the charge of the bare nucleus. The population densities depend linearly on the ground level population densities and tables are presented of two coefficients representing this relation for some of the lower excited levels.
The calculations include the processes of excitation, de-excitation, ionization by electron collision, spontaneous radiative decay, three-body recombination and radiative recombination. Processes involving the absorption of photons are neglected and it is assumed that the free electrons have a Maxwellian distribution.
The validity of the calculations in the extremes of the ranges is discussed.
The calculations illustrate the transition from high densities where all the excited levels have nearly a Saha-Boltzmann population to low densities where the radiative capture-cascade model is valid.
From the population density of the excited levels, the power lost by line radiation by hydrogen-like ions, radiative recombination of electrons onto the bare nuclei and bremsstrahlung of the free electrons in the field of the bare nucler is calculated.
Since energy is lost by radiation, the total energy dissipated during the ionization of one hydrogen-like ion may be much greater than the simple ionization energy of the ion. This has been calculated for electron temperatures between 16 000Z2 °K and 256 000Z2 °K.