The theory of spectral lines in a plasma with quasistatic ions is reconsidered. The ion microfield distribution, generalized to include field gradients and higher-order derivatives, is introduced without decoupling the ion and electron subsystems. It is shown that in a self-consistent treatment of ion-electron correlations the calculations of line shifts requires a more complete theory than has been used in the past. It is shown that level shifts due to a time average of the radiator-plasma interaction are closely related to shifts due to ion field inhomogeneities at the radiator. These two shifting mechanisms are not independent and the analysis indicates how to avoid overcounting. As a result, the time average of the radiator-plasma interaction, usually associated with the so-called plasma polarization shift, is formally different from the equivalent expression given by theories which treat electron-ion correlations in an ad hoc fashion.

• Received 27 June 1983

DOI:https://doi.org/10.1103/PhysRevA.29.1366