Experimental investigation of indirectly-driven, ignition-like double- shell implosions
Abstract
An experimental campaign has recently been conducted on the Omega Laser to study the performance of indirectly-driven, ignition-like double-shell implosions. These targets are of interest as they provide a possible non-cryogenic path to ignition on the NIF. In particular, these capsules were designed to produce significantly more DD neutron yield from the compressional phase of the implosion as opposed to that generated at shock convergence alone. This goal imposes severe constraints on the capsule tolerances and the driving laser pulse shape, both of which have been optimized to minimize the effects of interfacial mix between the inner shell and the DD fuel. The capsules, which have an outer diameter of 550μ, are assembled from a central DD-filled CH shell surrounded by a series of precision-machined hemispherical shells of 50mg/cc carbon foam and an outer ablator of Br-doped CH, all of which have dimensional tolerances of less than 5µm. The results of the experiments are described and compared with 2D integrated hohlraum simulations. The DD neutrons yields were observed to be remarkably consistent and were approximately 20 times the predicted yield due to shock convergence alone. Directions for further improvement in capsule performance are discussed.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2003
- Bibcode:
- 2003APS..DPPLO2005R