THERMOS: Сonsistent solution of the radiation transport equation with level kinetics in simple geometries

The THERMOS code was used to calculate the properties of dense photoionized aluminum plasma. The case is based on an experiment carried out at the LCLS, where an aluminum film was irradiated with intense X-ray radiation with a photon energy of 1650 eV using a free-electron laser. The evolution of the aluminum plasma was considered, the populations of states and the emission spectrum were calculated. The main attention was paid to the study of the effects associated with nonstationarity and ionization potentials depression due to high density using collisional-radiative model.

Simulation of dense aluminum plasma under intense X-rays

Kim¹,

Vichev²,

Solomyannaya³

et al. 2021

Approximate methods of taking into account nonequilibrium radiation field in plasmas

Grushin¹,

Vichev²,

Kim³

et al. 2022

In certain plasma physics problems it is very important to take into account nonequilibrium of the radiation field. Primarily it concerns laser and pinch plasmas characterized by stiff density and temperature gradients. In this paper, a method is presented for approximate accounting for the nonequilibrium of the radiation field in plasmas, which is based on the approximation of the real radiation field by a parameterized Planckian function with subsequent interpolation of plasma properties on a certain tabulated basis. A comparison with several other approximate methods for taking into account the plasma nonequilibrium showed that the proposed method has promising potential.

Simulation of strongly photoionized silicon plasma

Vichev¹

2022

The work demonstrates the process of simulation a strongly photoionized silicon plasma with parameters close to astrophysical. The calculations were carried out within the model of collisional-radiative equilibrium. The obtained results were verified by comparison with the results of other participants of the codes comparison workshop. A comparative analysis of the results with the experimentally measured spectrum of soft X-ray transmission through a layer of photoionized silicon plasma is carried out.