Three stages of ICF implosion and the hydrodynamic instabilities operating at each stage.
Cartoon showing the penetration and absorption of M-band radiation ahead of an ablation-driven shock front in the geometry of an ICF implosion producing perturbations due to anisotropic microstructures in Be.
Schematic of target package used in Trident experiments showing drive beam emanating from right illuminating gold foil and VISAR measuring target free surface velocity from the left.
Measured source M-band spectrum (dashed curve) for one variation in filter and Au thickness and the inferred target absorption (symbols) after comparing the target transmission and source spectrum. Absorption from published data (Ref. 18) shown for comparison.
Static (left) and dynamic (right) TIDI images showing preheat-induced roughening in large-grained pure Be targets.
Static (left) and dynamic (right) TIDI images showing preheat-induced roughening in fine-grained Cu-doped Be targets.
Power spectral density of preheat roughened surface in three different target types. Dashed lines show the static roughness prior to x-ray pulse and solid lines show dynamic roughening at 3 ns.
Meyer–Blewett growth rate assuming 3 Mbar shock in Be impacting DT including an initial velocity perturbation. Measured preheat-induced surface spectrum was used as the unshocked initial amplitude.
Experimental and simulated velocity profiles for (a) uniformly doped BeCu targets and (b) commercially pure Be. The simulated profiles used a scaled version of the measured M-band spectrum from a filter-only shot (1.8–4.0 keV) and a second simulation with an additional 1.5–1.8 keV contribution. Tagged arrows show the decrease in velocity from the peak to the next minimum. Simulations do not show any evidence of velocity increases following the peak, suggesting the presence of spallation in the experiments.
Simulated temperature profiles (taken at 2 ns) for uniform doping ( thick) and undoped Be ( thick). The diagnostic side corresponds to the surface at which VISAR and TIDI measurements were taken and the source side is the target surface closest to the Au plasma.
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