Parametrization of Mean Radiative Properties of Optically Thin Steady-State Plasmas and Applications

Plasma radiative properties play a pivotal role both in nuclear fusion and astrophysics.They are essential to analyze and explain experiments or observations and also in radiative-hydrodynamics simulations.Their computation requires the generation of large atomic databases and the calculation,by solving a set of rate equations,of a huge number of atomic level populations in wide ranges of plasma conditions.These facts make that,for example,radiative-hydrodynamics in-line simulations be almost infeasible.This has lead to develop analytical expressions based on the parametrization of radiative properties.However,most of them are accurate only for coronal or local thermodynamic equilibrium.In this work we present a code for the parametrization of plasma radiative properties of mono-component plasmas,in terms of plasma density and temperature,such as radiative power loss,the Planck and Rosseland mean opacities and the average ionization,which is valid for steady-state optically thin plasmas in wide ranges of plasma densities and temperatures.Furthermore,we also present some applications of this parametrization such as the analysis of the optical depth and radiative character of plasmas,the use to perform diagnostics of the electron temperature,the determination of mean radiative properties for multicomponent plasmas and the analysis of radiative cooling instabilities in some kind of experiments on high-energy density laboratory astrophysics.Finally,to ease the use of the code for the parametrization,this one has been integrated in a user interface and brief comments about it are presented.

Collisional-Radiative Calculations of Optically Thin and Thick Plasmas Using the Computational Package ABAKO/RAPCAL

Non-local thermodynamic equilibrium(NLTE)conditions are universal in laboratory and astrophysical plasmas and,for this reason,the theory of NLTE plasmas is nowadays a very active subject.The populations of atomic levels and radiative properties are essential magnitudes in the study of these plasmas and the calculation of those properties relies on the so-called collisional-radiative(CR)models.However,the complexity of these models has led to the development of numerous collisionalradiative codes and this is a current research topic in plasmas.In this work is presented a versatile computational package,named ABAKO/RAPCAL,to calculate the populations of atomic levels and radiative properties of optically thin and thick,lowto-high Z,NLTE plasmas.ABAKO/RAPCAL combines a set of analytical approximations which yield substantial savings in computing running time,still comparing well with more elaborated codes and experimental data.In order to show the capabilities of the code and the accuracy of its results,calculations of several relevant plasma magnitudes for various plasma situations are shown and compared.