Two-dimensional capsule-hohlraum designs for the national ignition facility

This article describes 250, 280, and 350 eV drive temperature copper-doped Be [Be(Cu)] two-dimensional (2-D) capsule-hohlraum designs for the National Ignition Facility (NIF) [Paisner , Laser Focus World 30, 75 (1994)]. These capsule-hohlraum designs are a follow-on to the previous one-dimensional c apsule designs of Bradley and Wilson [Phys. Plasmas 6, 4293 (1999)]. It is shown that a 2-D 350 eV capsule-hohlraum design scaled from the successful 330 eV design does not ignite, mostly due to poor symmetry. In addition, th e 350 eV capsule hohlraum design requires the full 500 TW of the NIF design and 1.66 MJ of the maximum 1.8 MJ designed energy output. It is possible t o design a capsule-hohlraum combination that achieves ignition and burn wit h peak radiation temperatures of 250, 280, and 330 eV. These designs use fr om 1.3 to 1.6 MJ of laser energy and the successful designs have yields of 16-20 MJ. Changes in symmetry and yield due to changing the focal point of the inner and outer laser cones were examined. The 280 eV capsule can toler ate pointing changes of 40-100 mum before the yield drops by 50%, while eve n a 40 mum pointing change for the 250 eV capsule causes the yield to drop by a factor of 2 to 100. (C) 2001 American Institute of Physics.