E. Mínguez

RAPCAL code: A flexible package to compute radiative properties for optically thin and thick low and high-Z plasmas in a wide range of density and temperature

Radiative properties are fundamental for plasma diagnostics and hydro-simulations. For this reason, there is a high interest in their determination and they are a current topic of investigation both in astrophysics and inertial fusion confinement research. In this work a flexible computation package for calculating radiative properties for low and high Z optically thin and thick plasmas, both under local thermodynamic equilibrium and non-local thermodynamic equilibrium conditions, named RAPCAL is presented. This code has been developed with the aim of providing accurate radiative properties for low and medium Z plasmas within the context of detailed level accounting approach and for heavy elements under the detailed configuration accounting approach. In order to show the capabilities of the code, there are presented calculations of some radiative properties for carbon, aluminum, krypton and xenon plasmas under local thermodynamic and non-local thermodynamic equilibrium conditions.

A parametric potential for ions from helium to iron isoelectronic sequences

Abstract It is shown that a new family of analytical potentials with one, two or three parameters produces similar results to those obtained with more complex models. The parameters of the potential are obtained by an iterative procedure with a selfconsistent relativistic potential that has corrections at large distances, and considers the exchange and correlation energy by means of the local density approximation. The analysis of the results obtained with the family of analytical potentials (eigenvalues, eigenfunctions and atomic energies) allowed us to propose a parametric potential with one or two parameters that depends on the electron number of ion. These parameters were fitted to power series in Z for intermediate and highly ionized atoms from helium to iron isoelectronic sequences. Finally, using this analytic potential, we obtained oscillator strengths for lithium and soduim like gold, which are compared with other models.

An effective analytical potential including plasma effects

Abstract In this work, we have developed a method to build an effective analytical potential for ions in slightly nonideal plasmas. This proposed potential is obtained from an analytical isolated potential with one or two parameters depending on the total number of electrons of the ion. The plasma effects are included by means of the linearized Debye–Huckel approximation taking into account the reaction of the plasma-charge density to the optical electron. Due to the influence of the plasma over the atomic potential, this permits to obtain level energies and wave functions as a function of the inverse of Debye radius, the quantum numbers, the nuclear charge, the bound electron number and the ionization state of the ion. Also, we compare the analytical effective potential proposed in this paper with other ones very well known in the available literature.

A screened hydrogenic model using analytical potentials

The screened hydrogenic model and analytical potentials are tools widely used for atomic calculation of dense plasma physics. In this paper, we present a simple method to obtain screened hydrogenic energy levels and wave functions from analytical potentials for ions. Atomic data obtained using this model are compared satisfactorily with results of similar models and of more sophisticated self-consistent codes.

ANALYTICAL EXPRESSIONS FOR THE n-ORDER MOMENTA OF CHARGE DISTRIBUTION FOR IONS

Abstract In this work a family of four analytic expressions for the n-order momenta of the charge distribution for ions, 〈rn〉, depending on three, two, or one parameters will be presented. These expressions are derived through the use of electronic charge densities obtained from a family of four analytical potentials. The parameters in the expressions were obtained for ions in the ground state from helium to uranium isoelectronic sequences. The use of these parameters allows to find analytical expressions for the 〈rn〉 as functions of the nuclear charge, Z, only. Finally, the results obtained are compared with results computed by different methods.

Determination of corona, LTE, and NLTE regimes of optically thin carbon plasmas

In this work is accomplished the determination of the corona, local and non-local thermodynamic equilibrium regimes for optically thin carbon plasmas in steady state, in terms of the plasma density and temperature using the ABAKO code. The determination is made through the analysis of the plasma average ionization and ion and level populations. The results are compared whit those obtained applying Griem’s criterion. Finally, it is made a brief analysis of the effects of the calculation of level populations assuming different plasma regimes in radiative properties, such as emissivities and opacities.

Determination and analysis of plasma parameters for simulations of radiative blast waves launched in clusters of xenon and krypton

In this work several relevant parameters and properties for krypton and xenon plasmas are analyzed, such as, for example, the average ionization, the plasma thermodynamic regimes, the radiative power losses and the mean opacities. This analysis is performed in a range of density and temperature typically found in laboratory experiments to generate radiative blast waves in laser-heated clustered plasmas. A polynomial fit of those parameters is also presented. Finally an analysis of the thermal cooling instability is performed.

Calculation of the radiative opacity of laser-produced plasmas using a relativistic-screened hydrogenic model

Abstract In this work, we use a relativistic-screened hydrogenic model to compute the radiative opacity of laser-produced plasmas. The model is based on a set of screening charges which allow one to easily calculate atomic properties of isolated ions. These screened charges have been fitted to a fourth-order polynomial depending on the nuclear charge Z for ground and single excited states of ions belonging to the isoelectronic sequences comprised between He-like to U-like. In the opacity model used, ionic populations are obtained by solving the Saha equation including degeneracy corrections. Bound–bound transitions are determined using a Voigt profile for line shape, which includes natural, collisional, Doppler and UTA widths. Bound–free and free–free opacities are evaluated using the Kramer cross-sections with appropriate corrections. Scattering processes are computed through the use of the Thomson formula with corrections. The results are compared with other screened hydrogenic models and more sophisticated self-consistent codes.

Analytical opacity formulas for ICF elements

Local Thermodynamic Equilibrium (LTE) opacity codes have been developed by the Instituto de Fusion Nuclear (DENIM) during the last years. JIMENA code (Laser and Particle Beams 6 (1998) 265; Laser and Particle Beams 10 (1992) 651) is an opacity code that solves self-consistently, for each temperature and density, the radial Dirac equation with a local spherically symmetrical potential. Very recently we have developed a new opacity code, called ANALOP, that uses an analytical potential (JQSRT 54 (1995) 621), which can include density and temperature effects for atomic data calculations. Opacities are determined with these two codes for selected elements at different plasma conditions. This work is focused on the determination of Rosseland and Planck mean analytical formulas for several single elements used in ICF targets. A scaling law of these mean opacities is given as a function of the plasma parameters: electron temperature and plasma density. These opacities have been tested with numerical results from other codes and with available experimental results.

Developments and comparison of two denim opacity models

Abstract Local Thermodynamic Equilibrium (LTE) opacity codes have been developed at DENIM during the last years. JIMENA 1 , 2 is an opacity code that solves self-consistently, for each temperature and density, the radial Dirac equation with a local spherically symmetrical potential. Very recently we have developed a new opacity code, called ANALOP, that uses an analytical potential [3] , which can include density and temperature effects for atomic data calculations. Opacities are determined with these two codes for selected elements at different plasma conditions.