Indirect-drive radiation uniformity in tetrahedral hohlraums
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)
Tetrahedral hohlraums, by which are understood spherical hohlraums with four laser entrance holes (LEH{close_quote}s) placed at or near the vertices of a tetrahedron, are proposed for the National Ignition Facility (NIF) [J. Lindl, Phys. Plasmas {bold 2}, 3933 (1995)] and the upgraded OMEGA laser [T. R. Boehly {ital et} {ital al}., Rev. Sci. Instrum. {bold 66}, 508 (1995)]. All but four of the 48 NIF beams can irradiate a tetrahedral hohlraum, assuming that 72 beam ports are provided to accommodate direct drive. On OMEGA, the target chamber provides an exact tetrahedral symmetry, permitting the irradiation of tetrahedral hohlraums with all 60 beams. Hohlraum designs are optimized using a new three-dimensional view-factor program called Buttercup, which traces all beam paths through the hohlraum and calculates the radiation flux on the capsule for different values of the albedo. Good irradiation uniformity ({approximately}2{percent} rms) can be obtained on the capsule at all times during the implosion, even with identical beam temporal histories, in contrast to the case of cylindrical hohlraums where {open_quote}{open_quote}beam phasing{close_quote}{close_quote} is needed. {copyright} {ital 1996 American Institute of Physics.}
- Research Organization:
- Univ. of Rochester, NY (United States)
- DOE Contract Number:
- FC03-92SF19460
- OSTI ID:
- 383795
- Journal Information:
- Physics of Plasmas, Vol. 3, Issue 10; Other Information: PBD: Oct 1996
- Country of Publication:
- United States
- Language:
- English
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