Broadening of the Lyman-αlines of hydrogen and hydrogenic ions in dense plasmas

Theoretical estimates are proposed for the profiles of the central components of Lyman-α lines for conditions where Stark effects caused by high- and low-frequency fields are more important than fine-structure splitting. An experiment-theory discrepancy of a factor {~}2 for hydrogen Lyman-α lines is removed by allowing also for electron-produced low-frequency fields.