Stark effect in three-dimensional stochastic electric fields and a static magnetic field of a helium plasma

Abstract

Atomic absorption spectra of the He I plasma in the static magnetic field in the absence of laser radiation are different from spectra in the presence of laser radiation. Especially, it has been theoretically predicted that the spectral shift of the satellite line, which is seen in the latter case, does not exist in the former case. In this paper, the effect of three-dimensional high-frequency electric fields on the σ+, σ−, and π components of the allowed 1 1S0-3 1P1 transition and the forbidden 1 1S0-3 1D2 lines in atomic absorption spectra of the He I plasma in a static magnetic field in the absence of a laser beam is investigated from the coupled equations for the probability amplitudes of atomic states. It is shown that they should give rise to a spectral shift of the allowed lines and satellites about forbidden lines. The calculation reveals that the shift is proportional to the mean-square stochastic electric field, and that the ratio of the intensity of the near satellite to that of the far satellite is different from the ratio obtained by the second-order perturbation theory or the three-level rotating-wave approximation. Discussion is given for the validity of this theory.