A new, highly unusual shift of hydrogen-like spectral lines in dense plasmas

Abstract We present a new theoretical contribution to the shift of hydrogen-like spectral lines called a dipole ionic–electronic shift (DIES). Its main feature is a highly nonlinear , sign-varying dependence on the electron density, which distinguishes the DIES from the previously known shifts. The DIES has been already experimentally confirmed for the Balmer-alpha line of hydrogen emitted from a laser-produced underwater plasma. We show that for hydrogen-like lines of multicharged ions in plasmas approaching non-ideality, the DIES is practically as important as for hydrogen lines.