Broadening of Lyman lines of hydrogen and hydrogenic ions by low-frequency fields in dense plasmas

A previously developed extension of the quasistatic approximation which allows for the broadening of hydrogen lines by low-frequency fields is applied to the first four Lyman lines of hydrogen, ionized helium, CVI, and ArXVIII. It is demonstrated numerically that the low-frequency Stark broadening is Gaussian in the case of relatively small dynamical corrections. Extrapolation of this Gaussian approximation to cases with large corrections leads to good agreement with measurements of the Lyman-$\alpha$, -$\beta$, and -$\gamma$ lines of hydrogen and allows the prediction that the Lyman-$\delta$ should retain its central dip.