J. Phys. IV France
Volume 133, June 2006
Page(s) 233 - 235
Publié en ligne 16 juin 2006
Inertial Fusion Sciences and Applications 2005
J.-C. Gauthier, et al.
J. Phys. IV France 133 (2006) 233-235

DOI: 10.1051/jp4:2006133047

Polar direct drive - Ignition at 1 MJ

S. Skupsky, R.S. Craxton, F.J. Marshall, R. Betti, T.J.B. Collins, R.Epstein, V.N. Goncharov, I.V. Igumenshchev, J.A. Marozas, P.W. McKenty, P.B. Radha, J.D. Kilkenny, D.D. Meyerhofer, T.C. Sangster and R.L. McCrory

Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, NY 14623, USA

Target designs to achieve direct-drive ignition on the NIF using the x-ray-drive beam configuration are examined. This approach, known as polar direct drive (PDD), achieves the required irradiation uniformity by repointing some of the beams toward the target equator, and by increasing the laser intensity at the equator to compensate for the reduced laser coupling from oblique irradiation. Techniques to increase the equatorial intensity can include using phase plates that produce elliptical spot shapes, increasing the power in beams directed toward the equator, and using a ring offset from the equator to redirect rays toward the target normal. The requirements for beam pointing, power balance, single-beam smoothing, and inner-ice-surface roughness are examined. Designs with an incident laser energy of 1.0 MJ are presented. The simulations use the 2-D hydrocode DRACO with 3-D ray trace to model the laser irradiation and Monte Carlo alpha particle transport to model the thermonuclear burn.

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