Influence of magnetic-field-caused modifications of trajectories of plasma electrons on spectral line shapes: Applications to magnetic fusion and white dwarfs

Abstract

A general framework for calculating shapes of hydrogen (or deuterium) spectral lines in strongly-magnetized plasmas with the allowance for spiraling trajectories of perturbing electrons has been developed. It has been shown that in this situation the first order term Φ(1)(B) of the Dyson expansion of the electron broadening operator does not vanish – in distinction to the case of rectilinear trajectories, where the first non-vanishing term appeared only in the second order. An example of the Lyα line has been used to illustrate the effects of the spiraling trajectories. It has been shown that the shape of each of the two σ-components can become a doublet: in addition to the shifted component, there can appear also an unshifted component. Moreover, the shape of each of the two σ-components can also become a triplet: in addition to the shifted and unshifted component, there can appear also a component shifted to the opposite wing of the line. Both the positions and the intensities of the shifted components depend strongly on the magnitude of Φ(1)(B). The primary effect in the entire spectral line is a significant increase of the ratio of the intensity of the central peak to the intensity of any of the two lateral peaks.As practical examples, magnetic fusion plasmas and plasmas of DA white dwarfs have been considered. It is shown that for both of these, physically very different objects, the allowance for the spiraling trajectories of perturbing electrons can be important.