Radiation symmetry studies in double-Z-pinch hohlraums on Z using 4.7-mm capsules*
Abstract
Via x-ray backlit capsule shell distortion measurements, the time-averaged polar radiation uniformity in a 70 eV high-yield-scale double-z-pinch-driven hohlraum (cylindrical) on Sandia National Laboratories Z accelerator has recently been measured to the 3.0 +/- 1.4% level on the best shots [Bennett et al., Phys. Plasmas, in press]. This 3.0% symmetry would scale to 0.9% at 220 eV HY (high yield) conditions on a dual power-feed HY accelerator, close to that required for ignition, due to increased hohlraum wall albedo. These studies were performed in non-optimized hohlraums that were dominated by a P2 Legendre mode, controlled by hohlraum length [Vesey et al., Phys. Plasmas 10, 1854 (2003)], using 2.13-mm-diam plastic capsules. Experiments in Sept 2003 will use Ge-doped thin shell capsules of 4.7-mm diameter in order to improve the accuracy of the symmetry measurement, while replicating the case-to-capsule ratio of the HY design. Both P2 and P4 will be varied in these experiments, and this paper will focus on the most symmetric implosions that result.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2003
- Bibcode:
- 2003APS..DPPLO2010B