Session CO1 - Compression and Burn.
ORAL session, Monday afternoon, November 15
Room 201/202, SCC
Imploding direct-drive double shell targets may provide an alternative, non-cryogenic path to ignition on the National Ignition Facility (NIF) and the Laser Megajoule (LMJ). Experiments are being pursued at OMEGA to understand the hydrodynamics of these implosions and the possibility of scaling to NIF designs. We have used 40 beams from the OMEGA laser to directly drive the capsules, and we have used the remaining 20 beams to backlight the imploding shells from two different directions at multiple times. Because the number of beams was fewer than the 60 normally used to drive a capsule symmetrically at OMEGA, we use offset pointing to produce relatively uniform drive. Offset pointing may also be used at other lasers not normally designed for uniformly driven direct drive targets, such as the NIF an LMJ. We will review the recent experiments to measure the zero-order hydrodynamics of the targets, and the symmetry of the drive. We use two-view x-ray radiography of the capsules. Experiments were pursued using direct drive in which the M-band effect, experienced in the indirect drive experiments, could be eliminated or controlled. We will review the method used to radiograph the targets and the techniques used to extract useful information to compare with calculations. The effect of imperfections in the target construction will be shown to be minimal during the initial stage of the implosion. (LA-UR-04-4939) This work was performed at Los Alamos National Lab under the auspices of the US DOE under contract No. W-7405-ENG-36