The influence of the resonance effects on the radiative characteristics of helium plasma

In the present work, the influence of an alternating circularly polarized electric field on the energy spectrum of the He atom is studied. The calculations are performed by the method of the energy matrix diagonalization of an atom in the electric field. This method has allowed us to study the behaviour of the helium energy spectrum from the same numerical procedure under resonant and non-resonant excitations by the electric field. Based on the calculation results, we have found that the resonance effects take place not only in the vicinity of resonance, but they influence the shift directions of the Stark states even under non-resonant excitation. Additionally, we have established that the helium energy spectrum behaves consistently in the electric field. The results obtained have allowed us to clarify mechanisms of the influence of the resonance effects on the radiative characteristics of helium plasma

Modelling line profiles in the helium spectra excited by an alternating electric field

A unified approach is developed for calculating profiles of spectral lines of atoms in an alternating electric field. This numerical method is based on diagonalization of the energy matrix of an atom in the electric field. To calculate the Stark profile of a spectral line, a formula is proposed, where the profile width contains an explicit dependence on the parameters of the electric field. The algorithm of the method is implemented in the software package StarkD written in FORTRAN and Maple. In the framework of the proposed approach, a computer simulation of the spectral lines of the helium atom in alternating electric fields of linear and circular polarizations is performed