Redshift of the Lyman-αemission line of H-like ions in a plasma environment

Abstract

We present a critical assessment of the applicability of the Debye-H\uckel (DH) approximation to the redshift of the Lyman-$\ensuremath{\alpha}$ emission line of the H-like ions under a dense plasma environment. By carefully considering the $2p\ensuremath{\rightarrow}1s$ transition spatially and temporally, our investigation suggests that the DH approximation may be applied to a limited number of H-like ions, such as the ones with $Z$ between 5 and 18 or with $Z$ greater than 50. Our numerical calculation, in fact, leads to quantitative agreement with the observed redshift of the well-isolated Lyman-$\ensuremath{\alpha}$ line at plasma density of the order of $1\ifmmode\times\else\texttimes\fi{}{10}^{22}$ ${\mathrm{cm}}^{\ensuremath{-}3}$ or higher with an electron temperature of several hundred eV of H-like ${\mathrm{Al}}^{12+}$. Our study also yields simulated data consistent with those from more elaborate quantum mechanical approaches.