T. Fujimoto, H. Sahara, G. Csanak and S. Grabbe


Atomic States and Collisional Relaxation in Plasma Polarization Spectroscopy: Axially Symmetric Case

Date of publication:

Oct. 1996

Key words:

population, alignment, anisotropy, velocity distribution, density matrix, collisional relaxation, polarization, colIisional-radiat ive model


An ensemble of atoms (or ions) is described in terms of the density matrix, and two quantities, population and alignment, are assigned to each atomic level for axially symmetric plasma environment. Collisional relaxation is treated semiclassically as transitions between vectors in the Liouville space and interpreted as elastic or inelastic transitions among the population and the alignment of the levels. A spatially anisotropic velocity distribution of perturbers is expanded in terms of Legendre polynomials, and rate coefficients are defined for the transitions. A set of rate equations are constructed for the system of populations and another set for that of alignments. In the case of an isotropic Maxwellian distribution of perturbers the former reduces to the conventional collisional-radiative model describing the ionizing plasma component of populations. As an example, berylliumlike oxygen in an anisotropic plasma environment is treated by this mehod.

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