Laser-Driven Dynamic Hohlraums: Implosions

The Laser-Driven Dynamic Hohlraum (LDDH) is a direct-drive analogue to the dynamic hohlraums fielded on the Sandia Z machine\footnote{ Matzen, M. K. et al., Phys. Plasmas \textbf{12}, 055503 (2005).}. In the LDDH, a radiatively collapsed shock driven in a xenon-filled capsule confines radiation in a spherically convergent geometry, leading to a small, hot hohlraum. Fielding a second capsule inside the LDDH results in a system which is significantly less vulnerable to mix than a hydrodynamically coupled double-shell implosion. Previously\footnote{ Herrmann, Mark, BAPS, November 2003 (BI2.003).} we have reported on our observations of the radiatively collapsed shock (RCS) and ablation of a silver tracer layer. Since that time, we have used the LDDH to drive implosions in D$_{2}$-filled glass capsules placed inside the LDDH and observed yields of about 4X10$^{9}$ neutrons ($\sim $10{\%} of two-dimensional predictions) and the presence of significant x-ray emission from stagnation of ablated glass with the RCS. We will show our results from implosion experiments and comparisons with simulations.