Calculated X-Ray Backlighting Images of Mixed Imploded Targets

Shell-core mixing, which can occur during the deceleration phase of a laser-driven implosion, is believed to be the major limitation on target performance. This mixing is brought about by a hydrodynamic instability during the deceleration phase, which is seeded by instability generated during the acceleration phase due to laser and target no nun if or mi tie^.^ The image of the x-ray emission from the shell (enhanced by high-Z doping) was used in recent experiments to diagnose this e f f e ~ t . ~ ~ e c a u s e of the limb effect, this emission appears in the image in the form of a ring; mixing causes this emission ring to move toward smaller radii. However, the difference in the image characteristics between mixed targets and unmixed targets, which compress to a smaller radius, is subtle: in the former case, the outward drop in intensity is slower. Thus, a smaller compression and mixing tend to cancel each other's effect on the position of the ring in the image.