Modeling hydrodynamics, magnetic fields, and synthetic radiographs for high-energy-density plasma flows in shock-shear targets

Abstract

Three-dimensional FLASH radiation-magnetohydrodynamics (radiation-MHD) modeling is carried out to study the hydrodynamics and magnetic fields in the shock-shear derived platform. Simulations indicate that fields of tens of Tesla can be generated via Biermann battery effect due to vortices and mix in the counter-propagating shock-induced shear layer. Synthetic proton radiography simulations using MPRAD and synthetic X-ray image simulations using SPECT3D are carried out to predict the observable features in the diagnostics. Quantifying the effects of magnetic fields in inertial confinement fusion (ICF) and high-energy-density (HED) plasmas represents frontier research that has far-reaching implications in basic and applied sciences.

Proton imaging of high-energy-density laboratory plasmas

“…A variation on the beamlet technique is to use an object (such as a mesh, mask, or pepperpot) to subaperture the proton beam into many beamlets (Sokollik et al, 2008;Johnson et al, 2022), down to a few "pencil" beamlets (Lu et al, 2020), or even just down to a single beamlet (Chen et al, 2020). This allows one to probe areas of specific interest in a limited fashion that is more easily detectable (in terms of deflection) or to streak the beamlet in time.…”

“…II.C.3. When this is done, successful measurements of electromagnetic fields in dense plasma can be made: Romagnani et al (2019) used qTrace particle-tracing simulations that included a scattering model to successfully diagnose the time evolution of fastelectron-induced current filaments in dielectric foams, while Lu et al (2020) showed that, provided that scattering was included in supporting particle-tracing simulations, magnetic fields generated by the Biermann battery at a shocked shear layer in a dense foam could be observed. Particle-tracing simulations of proton beams that have been performed using full particle-in-cell (PIC) codes (Huntington et al, 2015) are capable of including another physics effect (albeit one that is usually not important): the beam's feedback on the electromagnetic fields being imaged via collisionless interaction mechanisms.…”

“…26(f) and 27(g)] with either transverse (Gao et al, 2012) or longitudinal (Gao et al, 2013) proton imaging of CH targets. More recent experiments have attempted to look at the self-generated magnetic fields inside denser HED shock-tube targets, where Coulomb scattering is an issue (Lu et al, 2020) and where the fields can change the heat flow in these targets, thereby changing the instability growth (Sadler et al, 2022).…”

“…Some recent research suggests that this could have been an oversight. Lu et al (2020) provided a proof of concept for measuring magnetic fields in high-density (>1 g=cm 3 ) plasmas by utilizing small aperture proton beams in higher-density objects like a laser-driven shock tube, while Bott et al (2021a) used the broadening of caustic features by scattering in multiple proton images to simultaneously measure magnetic fields and areal densities. If such approaches were to be refined and extended, proton imaging could become a powerful diagnostic on a wider set of experiments than is currently the case.…”

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

“…Starting from initial surface roughness, signatures of 3D self-similar turbulent evolution were measured [174]. Complementary experiments at subscale laser energy have also evidenced self-generated magnetic fields by turbulence of the order of tens of teslas [175].…”