Generalized measurable ignition criterion for inertial confinement fusion

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 (ρRntot), the ion temperature (Tn), and the yield over clean (YOC=ratio of the measured neutron yield to the predicted one-dimensional yield). The YOC measures the implosion uniformity. The criterion can be approximated by χ=(ρRntot)0.8(Tn/4.7)1.7YOCμ>1 (where ρR is in gcm^-2, T in keV, and μ0.4-0.5) and can be used to assess the performance of cryogenic implosions on the NIF and OMEGA. Cryogenic implosions on OMEGA have achieved χ∼0.02-0.03.