Comment on “Stark shift and width of x-ray lines from highly charged ions in dense plasmas”

Abstract

We point out in this Comment a misleading remark made by Gu and Beiersdorfer [Phys. Rev. A 101, 032501 (2020)] that the Debye-H\"uckel (DH) model ``performs rather poorly'' compared with the ion sphere model is due to their questionable use of the Debye length by assuming the same mobility for the plasma electrons and ions. Actually, our recent works based on a judicious application of the DH approximation, which meets the spatial and temporal criteria, have led to good agreements with all the available line shift experimental measurements on $\ensuremath{\alpha}$ and $\ensuremath{\beta}$ emission lines of He-like ions.