First results from cryogenic target implosions on OMEGA
2002; American Institute of Physics; Volume: 9; Issue: 5 Linguagem: Inglês
10.1063/1.1458586
ISSN1527-2419
AutoresC. Stöeckl, Catalin Chiritescu, J. A. Delettrez, R. Epstein, V. Yu. Glebov, D. R. Harding, R. L. Keck, S. J. Loucks, L. D. Lund, R. L. McCrory, P. W. McKenty, F. J. Marshall, D. D. Meyerhofer, Samuel Finley Breese Morse, S. P. Regan, P. B. Radha, S. Roberts, T. C. Sangster, W. Seka, S. Skupsky, V. A. Smalyuk, C. Sorce, J. M. Soures, R. P. J. Town, J. A. Frenje, C. K. Li, R. D. Petrasso, F. H. Séguin, K. Fletcher, S. Paladino, C. Freeman, N. Izumi, R. A. Lerche, T. W. Phillips,
Tópico(s)High-pressure geophysics and materials
ResumoInitial results from direct-drive spherical cryogenic target implosions on the 60-beam OMEGA laser system [T. R. Boehly, D. L. Brown, R. S. Craxton et al., Opt. Commun. 133, 495 (1997)] are presented. These experiments are part of the scientific base leading to direct-drive ignition implosions planned for the National Ignition Facility (NIF) [W. J. Hogan, E. I. Moses, B. E. Warner et al., Nucl. Fusion 41, 567 (2001)]. Polymer shells (1-mm diam with walls <3 μm) are filled with up to 1000 atm of D2 to provide 100-μm-thick ice layers. The ice layers are smoothed by IR heating with 3.16-μm laser light and are characterized using shadowgraphy. The targets are imploded by a 1-ns square pulse with up to ∼24 kJ of 351-nm laser light at a beam-to-beam rms energy balance of <3% and full-beam smoothing. Results shown include neutron yield, secondary neutron and proton yields, the time of peak neutron emission, and both time-integrated and time-resolved x-ray images of the imploding core. The experimental values are compared with 1-D numerical simulations. The target with an ice-layer nonuniformity of σrms=9 μm showed 30% of the 1-D predicted neutron yield. These initial results are encouraging for future cryogenic implosions on OMEGA and the NIF.
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