We present new diagnostics for use in optical laser pump-X-ray Free Electron Laser(XFEL)probe experiments to monitor dimensions,intensity profile and focusability of the XFEL beam and to control initial quality and ho...We present new diagnostics for use in optical laser pump-X-ray Free Electron Laser(XFEL)probe experiments to monitor dimensions,intensity profile and focusability of the XFEL beam and to control initial quality and homogeneity of targets to be driven by optical laser pulse.By developing X-ray imaging,based on the use of an LiF crystal detector,we were able to measure the distribution of energy inside a hard X-ray beam with unprecedented high spatial resolution(~1 mm)and across a field of view larger than some millimetres.This diagnostic can be used in situ,provides a very high dynamic range,has an extremely limited cost,and is relatively easy to be implemented in pump-probe experiments.The proposed methods were successfully applied in pump-probe experiments at the SPring-8 Angstrom Compact free electron LAser(SACLA)XFEL facility and its potential was demonstrated for current and future High Energy Density Science experiments.展开更多
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 paramete...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.展开更多
In this paper, we present a model characterizing the interaction of a radiative shock(RS) with a solid material, as described in a recent paper(Koenig et al., Phys. Plasmas, 24, 082707(2017)), the new model is then re...In this paper, we present a model characterizing the interaction of a radiative shock(RS) with a solid material, as described in a recent paper(Koenig et al., Phys. Plasmas, 24, 082707(2017)), the new model is then related to recent experiments performed on the GEKKO XII laser facility. The RS generated in a xenon gas cell propagates towards a solid obstacle that is ablated by radiation coming from the shock front and the radiative precursor, mimicking processes occurring in astrophysical phenomena. The model presented here calculates the dynamics of the obstacle expansion,which depends on several parameters, notably the geometry and the temperature of the shock. All parameters required for the model have been obtained from experiments. Good agreement between experimental data and the model is found when spherical geometry is taken into account. As a consequence, this model is a useful and easy tool to infer parameters from experimental data(such as the shock temperature), and also to design future experiments.展开更多
基金The XFEL experiments were performed at the BL3 of SACLA with the approval of the Japan Synchrotron Radiation Research Institute(JASRI)(Proposals Nos.2014A8045,and 2014B8068)This research was partially supported by grants from Grants-in-Aid for Scientific Research(Kakenhi Grant Nos.15H02153 and 17K05729)+1 种基金the Core-to-Core Program on International Alliance for Material Science in Extreme States with High Power Laser of the Japan Society for the Promotion of Science(JSPS),from the X-ray Free Electron Laser Priority Strategy Program of the MEXT,contract 12005014,and within the state assignment of FASO of Russia(theme N01201357846)The part of work was supported by the Agence Nationale de la Recherche in the frame of the ANR project TurboHEDP(ANR-15-CE30-0011).
文摘We present new diagnostics for use in optical laser pump-X-ray Free Electron Laser(XFEL)probe experiments to monitor dimensions,intensity profile and focusability of the XFEL beam and to control initial quality and homogeneity of targets to be driven by optical laser pulse.By developing X-ray imaging,based on the use of an LiF crystal detector,we were able to measure the distribution of energy inside a hard X-ray beam with unprecedented high spatial resolution(~1 mm)and across a field of view larger than some millimetres.This diagnostic can be used in situ,provides a very high dynamic range,has an extremely limited cost,and is relatively easy to be implemented in pump-probe experiments.The proposed methods were successfully applied in pump-probe experiments at the SPring-8 Angstrom Compact free electron LAser(SACLA)XFEL facility and its potential was demonstrated for current and future High Energy Density Science experiments.
基金supported by the Agence Nationale de la Recherche under the ANR project TurboHEDP(ANR-15-CE30-0011)
文摘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.
基金supported by the Scientific Council of the Observatoire de Parisby COST(European COoperation in Science and Technology),action MP1208,with a Short-Term Scientific Mission
文摘In this paper, we present a model characterizing the interaction of a radiative shock(RS) with a solid material, as described in a recent paper(Koenig et al., Phys. Plasmas, 24, 082707(2017)), the new model is then related to recent experiments performed on the GEKKO XII laser facility. The RS generated in a xenon gas cell propagates towards a solid obstacle that is ablated by radiation coming from the shock front and the radiative precursor, mimicking processes occurring in astrophysical phenomena. The model presented here calculates the dynamics of the obstacle expansion,which depends on several parameters, notably the geometry and the temperature of the shock. All parameters required for the model have been obtained from experiments. Good agreement between experimental data and the model is found when spherical geometry is taken into account. As a consequence, this model is a useful and easy tool to infer parameters from experimental data(such as the shock temperature), and also to design future experiments.