A multidimensional measurable criterion for central ignition of inertial-confinement-fusion capsules is derived. The criterion accounts for the effects of implosion nonuniformities and depends on three measurable parameters: the neutron-averaged total areal density ($\rho R_n^{\mathrm{tot}}$), the ion temperature ($T_n$), and the yield over clean ($\mathrm{YOC}=\mathrm{\text{ratio}}$ of the measured neutron yield to the predicted one-dimensional yield). The YOC measures the implosion uniformity. The criterion can be approximated by $\chi =(\rho R_n^{\mathrm{tot}}{)}^{0.8}(T_n/4.7{)}^{1.7}{\mathrm{YOC}}^{\mu }>1$ (where $\rho R$ is in $\mathrm{g}{\mathrm{cm}}^{-2}$, $T$ in keV, and $\mu \approx 0.4–0.5$) and can be used to assess the performance of cryogenic implosions on the NIF and OMEGA. Cryogenic implosions on OMEGA have achieved $\chi \sim 0.02–0.03$.

• Received 5 January 2010

DOI:https://doi.org/10.1103/PhysRevLett.104.135002