New Class of Laboratory Astrophysics Experiments: Application to Radiative Accretion Processes around Neutron Stars

Abstract

Extreme radiative phenomena, where the radiation energy density and flux strongly influence the medium, are common in the universe. Nevertheless, because of limited or nonexistent observational and experimental data, the validity of theoretical and numerical models for some of these radiation-dominated regimes remains to be assessed. Here, we present the theoretical framework of a new class of laboratory astrophysics experiments that can take advantage of existing high-power laser facilities to study supersonic radiation-dominated waves. Based on an extension of Lie symmetry theory we show that the stringent constraints imposed on the experiments by current scaling theories can in fact be relaxed, and that astrophysical phenomena can be studied in the laboratory even if the ratio of radiation energy density to thermal energy and systems’ microphysics are different. The validity of this approach holds until the hydrodynamic response of the studied system starts to play a role. These equivalence symmetries concepts are demonstrated using a combination of simulations for conditions relevant to Type I X-ray burst and of equivalent laboratory experiments. These results constitute the starting point of a new general approach expanding the catalog of astrophysical systems that can be studied in the laboratory.

High Energy Density Radiative Transfer in the Diffusion Regime with Fourier Neural Operators

“…Marshak waves, a common type of driven supersonic radiative heat waves, play a key part in the physics of internal confinement fusion (ICF) [1][2][3][4], astrophysics [5][6][7] and other high energy density phenomena [8]. In most cases, a full description of the radiative transfer process is not required.…”

Extensive characterization of Marshak waves observed at the LIL laser facility

“…Radiation transfer plays an important role in many high energy density plasmas such as those encountered in astrophysics but also those produced in the laboratory. 1,2 In the indirect drive configuration of Inertial Confinement Fusion (ICF) experiments for instance, high-power laser beams energy focused inside a gold hohlraum is converted into x-rays. 3 X-ray energy absorption inside the cavity wall and reemission, depending on wall albedo, set the radiation field in the hohlraum and the performances of the implosion of the capsule containing the deuterium-tritium (DT) fuel ultimately.…”