Open AccessA collisional-radiative average atom model for hot plasmas
Author(s) -
Balazs F. Rozsnyai
Publication year - 1996
Language(s) - English
Resource type - Reports
DOI - 10.2172/489144
Subject(s) - radiative transfer , atomic physics , plasma , physics , atom (system on chip) , thermodynamic equilibrium , dipole , electron , quantum mechanics , embedded system , computer science
A collisional-radiative `average atom` (AA) model is presented for the calculation of opacities of hot plasmas not in the condition of local thermodynamic equilibrium (LTE). The electron impact and radiative rate constants are calculated using the dipole oscillator strengths of the average atom. A key element of the model is the photon escape probability which at present is calculated for a semi infinite slab. The Fermi statistics renders the rate equation for the AA level occupancies nonlinear, which requires iterations until the steady state. AA level occupancies are found. Detailed electronic configurations are built into the model after the self-consistent non-LTE AA state is found. The model shows a continuous transition from the non-LTE to the LTE state depending on the optical thickness of the plasma. 22 refs., 13 figs., 1 tab