Visualizing magnetically driven converging radiative shock generated in Z-pinch foil liner implosion

Abstract

A study of the evolution and structure of magnetically driven converging radiative shock waves generated in Z-pinch foil liner implosion at an 8-MA pulsed-power facility is presented. End-on extreme ultraviolet images show an inward propagating shock that is circular to <±5% as a function of azimuthal angle, with a standard deviation in the emission intensity of <±30%, implying good cylindrical symmetry. The launch time and shock trajectory are determined by linear fitting of the measured data, giving a shock speed of Mach 6. One-dimensional radiation hydrodynamics MULTI-IFE-Z simulations agree with the experimental observations qualitatively and confirm the existence of a radiative precursor. It is demonstrated with experiment and simulation that the radiative shock wave is generated by magnetic piston compression of dense plasma shell. Analytic estimates of the post-shock plasma conditions suggest that these Z-pinch magnetically-driven high-Mach shocks are strongly radiatively cooled. It is applicable to the optically thick downstream, optically thin upstream radiative shock regime; thus, it can be described by three-layer model, which potentially could be applied to scale studies of astrophysical shocks in the laboratory.

Study of radiative shocks using 2D interferometry and XUV spectroscopy

“…9,[23][24][25][26] They are considered as a test case of coupling between radiation and hydrodynamic, [27][28][29][30] which in turn need to be tested against dedicated experiments. In addition to a few experiments performed on electric pulsed power installations, [31][32][33] the majority of the experiments have been performed on high energy nanosecond laser installations, 11,[34][35][36][37][38][39][40][41][42] with laser intensity on the target of about 10 14 W/cm 2 . As radiative effects increase with the Mach number, most experiments have been performed in heavy gases like Xenon, at various initial pressures, where typical shock velocities are in the range of 50 km/s and are analyzed over a few nanoseconds.…”