Advanced Analytical Treatment of Shapes and Shifts of Hydrogenic Spectral Lines in Plasmas and its Applications

Abstract

This work presents a detailed analysis and improvement of various aspects of the theory of the Stark broadening of hydrogen and hydrogen-like ions for a broad range of dense plasma parameters, while looking at both the shape and shift of the spectral line. This was done in an effort to improve the fundamental understanding of Stark shapes and shifts of spectral lines in plasmas (by producing more accurate analytical results than previously existed) and to provide advanced diagnostic methods for determining the electron density. First, we introduced an additional source of the shift of hydrogen-like spectral lines arising from the configurations where the nearest perturbing ion is within the radiating atom/ion (“penetrating configurations”) and in this way eliminated the existing discrepancy of a factor of two between the theory and experiments. Second, we improved the diagnostic method for measuring the electron density using the asymmetry of spectral lines in dense plasmas by taking into consideration these penetrating configurations. Third, we developed a more accurate theory of the broadening of hydrogen-like spectral lines by plasma electrons by using a more accurate description of the electron trajectories. Fourth, for plasmas of magnetic fusion machines, we obtained analytical results for the line shapes under two entangled broadening mechanisms: broadening by the Lorentz field and Doppler broadening – for an arbitrary angle of observation, in distinction to what had previously been done. Fifth, we developed an advanced analytical theory of the Stark broadening of hydrogen/deuterium spectral lines by a Relativistic Electron Beam (REB) and in this way suggested the diagnostic of the development of the REB in magnetic fusion machine, allowing to timely mitigate such a development, which is disruptive for magnetic fusion machines.