Plasma Induced Line Shifts: New Light on an Old Controversy

Beyond the Linear Stark Effect: A Retrospective

“…The idea of PPS was elaborated, developed [99,153,154,156,170,[172][173][174]176,182,185] and criticized [160,167,175] in a great number of papers, and it is impossible to point out all of them here. As it was noted in [160], the PPS results, classified in [160] as the effect of initial electron correlations [161][162][163][164][165]167], could substantially overestimate the observations, because of the unaccounted for frequency-dependent dynamic contribution to the ion line shift [160,167,177], related to the dynamic screening of the electron perturbers in plasma [162,167].…”

“…It goes without saying that it is simpler to use an additional approximation, expanding the scattering amplitude and calculate the so called second-order shifts [157,158,160,164,169,171,177,182]. Griem calculated the second-order electron inelastic collision shifts due to the dipole interaction in the impact approximation with the account of transitions to the adjacent levels with n = n ± 1 [157,158].…”

“…This could be expected due to the operation with the same physical notions of screening in the ionized gas and the implementation of momentum representation for the wave functions of the perturbers [160,168]. We note that within the TPGF formalism the many calculations of the line shifts (mainly induced by electron collisions) were performed and their results were compared with available experimental data, while there are only a few such calculations within the DBI approach [177]. So, a more thorough study of the comparison of these approaches in view of their correspondence to the experimental data is required.…”