2D numerical study of the radiation influence on shock structure relevant to laboratory astrophysics

¹ Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, Madrid, Spain e-mail: matthias@din.upm.es
² Service d'Astrophysique, CEA/DSM/IRFU/SAp, Centre de Saclay, 91191 Gif-sur-Yvette, France
³ Laboratoire AIM, CNRS, CEA/DSM, Université Paris Diderot, 91191 Gif-sur-Yvette, France
⁴ LERMA, Observatoire de Paris, Université Paris VI, CNRS, 5 place J. Janssen, 92195 Meudon, France

Received: 23 November 2007
Accepted: 9 January 2009

Abstract

Context. Radiative shocks are found in various astrophysical objects and particularly at different stages of stellar evolution. Studying radiative shocks, their topology, and thermodynamical properties is therefore a starting point to understanding their physical properties. This study has become possible with the development of large laser facilities, which has provided fresh impulse to laboratory astrophysics.

Aims. We present the main characteristics of radiative shocks modeled using cylindrical simulations. We focus our discussion on the importance of multi-dimensional radiative-transfer effects on the shock topology and dynamics.

Methods. We present results obtained with our code HERACLES for conditions corresponding to experiments already performed on laser installations. The multi-dimensional hydrodynamic code HERACLES is specially adapted to laboratory astrophysics experiments and to astrophysical situations where radiation and hydrodynamics are coupled.

Results. The importance of the ratio of the photon mean free path to the transverse extension of the shock is emphasized. We present how it is possible to achieve the stationary limit of these shocks in the laboratory and analyze the angular distribution of the radiative flux that may emerge from the walls of the shock tube.

Conclusions. Implications of these studies for stellar accretion shocks are presented.