Effect of Laser Bandwidth on High-Performance, Cryogenic Implosions

The goal of the high-performance cryogenic implosions on the OMEGA laser is to find the largest generalized Lawson criterion\footnote{ R. Betti \textit{et al.}, Phys. Rev. Lett. \textbf{114}, 255003 (2015).} that is accessible with 30-kJ, direct-drive implosions ($\chi_{\mathrm{no}}_{\alpha }$ OMEGA). $\chi _{\mathrm{no}}_{\alpha }$ OMEGA can then be used to extrapolate to the laser{\-}driver parameters needed for ignition. A study of implosion limitations is needed to meet the above goal. The bandwidth imposed by Smoothing by Spectral Dispersion (SSD) was varied to change the laser imprint on target implosions. Neutron yield ($Y_{\mathrm{n}})$ and areal density ($\rho R)$ were used to measure the implosion performance. $Y_{\mathrm{n}}$ and $\rho R$ data clearly show an SSD dependence that increases as bandwidth increases then plateaus at the higher values of bandwidth. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE{\-}NA0003856.