(a) Pie diagram of the nominal PDD CH capsules shot on NIF and (b) image of the capsule that incorporated an equatorial defect. The lighter rings in the image are from reflected light.
Pre-shot simulated radiographs of the plain capsule implosion at fractional radii of (a) 0.75, (b) 0.50, (c) 0.25, and (d) full compression. Peak absorption varies from ∼10% in (a) to ∼50% in (d).
(a) The schematic view for backlit and self-emission radiographs as observed from the equatorial diagnostic insertion manipulator (DIM) located at spherical coordinate angles (90°, 78°), (b) backlit radiograph from shot N120730 (1.5 mm × 1.5 mm image size) at 2.62 ns into the implosion of the capsule with the equatorial defect, and (c) x-ray self-emission image of the same capsule at 2.87 ns. The dark region to the right of the capsule in (b) is absorption from the fill tube that is observed entering from the target positioner located at angles (90°, 239°), 71° behind the plane of the image. Note the bright spots in the region of the defect in (b) and the dual bright spots at the edges of the defect in (c).
Comparison of the HYDRA simulated capsule radius (thin-shell center of mass) versus time (green line) with discrete radii extracted from the x-ray images for shots N120728 (red circles) and N120730 (blue squares). Measurement error bars are shown for each point.
Experimental (a) P2 asymmetry and (b) P4 asymmetry of the capsule compared to pre-shot predictions during the last half of the implosion. The P2 asymmetry is becoming more negative (oblate) as the capsule approaches minimum radius while the P4 asymmetry is increasing during this time.
Self-emission images of the first PDD D2-filled CH capsule implosion on NIF (N120728) at 2.9 ns as seen from (a) the equatorial DIM showing an offset of the upper and lower hemispheres, and (b) the polar DIM. The image frames are 0.75 mm square and the capsule is 320 μm in diameter. In contrast to the equator-hot image in (a), the image in (c) shows the HYDRA simulated equatorial self-emission radiograph of this capsule where emission at the equator is predicted to be lower than the rest of the hot spot.
(a) Log of the self-emission of shot N120728 as seen from the north pole of the NIF target chamber at 3.25 ns and (b) the 3-D simulated density contours from HYDRA at time 2.7 ns obtained using as-shot laser powers and improved laser spot sizes and skew prescription. The beams for the backlighter were removed from the direction where the bulge appears.
PDD laser pointing angles and defocus distances.
Comparison of predicted and experimental parameters for the two DIME shots.
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