Turbulent hydrodynamics experiments in high energy density plasmas: scientific case and preliminary results of the TurboHEDP project

Abstract

The physics of compressible turbulence in high energy density (HED) plasmas is an unchartered experimental area. Simulations of compressible and radiative flows relevant for astrophysics rely mainly on subscale parameters. Therefore, we plan to perform turbulent hydrodynamics experiments in HED plasmas (TurboHEDP) in order to improve our understanding of such important phenomena for interest in both communities: laser plasma physics and astrophysics. We will focus on the physics of supernovae remnants which are complex structures subject to fluid instabilities such as the Rayleigh-Taylor and Kelvin-Helmholtz instabilities. The advent of megajoule laser facilities, like the National Ignition Facility and the Laser Megajoule, creates novel opportunities in laboratory astrophysics, as it provides unique platforms to study turbulent mixing flows in HED plasmas. Indeed, the physics requires accelerating targets over larger distances and longer time periods than previously achieved. In a preparatory phase, scaling from experiments at lower laser energies is used to guarantee the performance of future MJ experiments. This subscale experiments allow us to develop experimental skills and numerical tools in this new field of research, and are stepping stones to achieve our objectives on larger laser facilities. We review first in this paper recent advances in high energy density experiments devoted to laboratory astrophysics. Then we describe the necessary steps forward to commission an experimental platform devoted to turbulent hydrodynamics on a megajoule laser facility. Recent novel experimental results acquired on LULI2000, as well as supporting radiative hydrodynamics simulations, are presented. Together with the development of LiF detectors as transformative X-ray diagnostics, these preliminary results are promising on the way to achieve micrometric spatial resolution in turbulent HED physics experiments in the near future.

Recent progress in quantifying hydrodynamics instabilities and turbulence in inertial confinement fusion and high-energy-density experiments

“…This is the culmination of a long thought research project [125][126][127]. Efforts are still underway to increase the spatial resolution of the x-ray radiographs with point-projection short pulse wire backlighters [128,129], with the aim of taking advantage of short pulse backlighter capabilities like the advanced radiographic capability (ARC) laser system at the NIF [130] or Petawatt Aquitaine Laser (PETAL) on LMJ [131]. These additional laser beamlines, based on OPCPA (Optical Parametric Chirped Pulse Amplification) technology [132], are extremely useful for generating bright X-ray sources [130] or protons beams [133] used, for example, to probe magnetized HED plasmas [134].…”

From ICF to laboratory astrophysics: ablative and classical Rayleigh–Taylor instability experiments in turbulent-like regimes

“…Additional PW beamlines [82,83] are valuable radiographic tools and deserve further investigation. We aim, therefore, at developing novel HED hydrodynamic platforms with micrometric spatial resolution, using LULI2000 as a stepping stone towards higher laser drive energies [84].…”

An online diagnosis technique for simultaneous measurement of the fundamental, second and third harmonics in one snapshot

“…High-power laser facilities have been established for research on inertial confinement fusion (ICF), high-energy-density (HED) physics, laboratory-scale astrophysics, etc. [1–4] . Typical examples of such facilities include the National Ignition Facility (NIF) in the USA [5–7] , the ShenGuang-II (SG-II) Facility in China [8, 9] , and the Laser Megajoule Facility (LMJ) in France [10, 11] .…”