Effect of collisions on motional Stark broadening of spectral lines

The shape of spectral lines in strongly magnetized plasmas is investigated theoretically in the framework of astrophysical research. Under certain conditions, the broadening of lines observed on white dwarf spectra is dominated by the so-called motional Stark effect, which occurs due to the Lorentz electric field v ($) over right arrow x B ($) over right arrow. If the plasma density is high enough, collisions between the emitter and perturbers change the atomic velocity v ($) over right arrow and the resulting motional Stark broadening is modified. We illustrate this modification through dedicated line shape calculations based on a stochastic model for the atomic velocity. A universal line shape formula, which is applicable to any isolated atomic line, is proposed for implementation in line shape codes.