A new asymmetry parameter characterizing the differences between the polarized π and σ gain components of the soft-x-ray J=0-1 lasing line of neon-like ions is calculated in the case of Ge 22+ assuming an electron distribution which is a weighted sum of an isotropic Maxwellian and a monoenergetic beam. Using a quasi steady-state collisional-radiative model, we determine in the weak amplification regime the relative populations of the upper M=0 and lower M 0, 1 =  magnetic sublevels of the lasing line as a function of electron density from 10 20 to 2 10 21 ´cm −3 . This model includes inelastic and elastic collisional transitions, as well as spontaneous radiative decay between all the 337 M-sublevels arising from the 75 lowest-lying Ge 22+ J-levels. The computations were performed for a temperature T e of the Maxwellian component between 1.2 10 6 ´and 8 10 6 ´K, a kinetic energy E 0 and a fraction f of the beam component in the ranges 1.5 20 keV -and 0.1% 10% -, respectively. The basic atomic data, such as level energies, radiative decay probabilities and inelastic collision strengths, were calculated with the flexible atomic code. However, some modifications of this code were made to get the collision strengths for transitions between M-sublevels due to impact with isotropic electrons as well as due to impact with an electron beam in the case of de-excitation. We find that the newly introduced asymmetry parameter may become significant under certain conditions of electron distribution corresponding to relatively low T e (1.2 10 2.5 10 6 6´-K) and E 0 (3-6 keV). The results reported here may be useful in the evaluation of the polarization degree of the J=0-1 x-ray laser output from a germanium plasma in the presence of fast directional electrons.

The relativistic distorted‐wave program of the flexible atomic code for calculating the cross sections for electron‐impact excitation of ions between fine‐structure levels is extended to get the multipole components of cross sections in the case of excitation by isotropic electrons. These components may be needed for interpreting the intensity and polarization of line emissions from thermal plasmas exposed to anisotropic radiations, such as the solar corona under photosphere irradiation. Illustrative numerical results are given for excitation of Si‐like Fe12+ between the , and levels. These results can be useful in the analysis of infrared forbidden lines emitted from the solar corona. A comparison is made with the only published work based on the semi‐relativistic distorted‐wave approximation, showing some agreement for the excitation and discrepancies for the weak transition .

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