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Cryogenic-target performance and implosion physics studies on OMEGA.

Authors :
Smalyuk, V. A.
Betti, R.
Boehly, T. R.
Craxton, R. S.
Delettrez, J. A.
Edgell, D. H.
Glebov, V. Yu.
Goncharov, V. N.
Harding, D. R.
Hu, S. X.
Knauer, J. P.
Marshall, F. J.
McCrory, R. L.
McKenty, P. W.
Meyerhofer, D. D.
Radha, P. B.
Regan, S. P.
Sangster, T. C.
Seka, W.
Short, R. W.
Source :
Physics of Plasmas; May2009, Vol. 16 Issue 5, p056301, 8p, 2 Diagrams, 7 Graphs
Publication Year :
2009

Abstract

Recent progress in direct-drive cryogenic implosions on the OMEGA Laser Facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] is reviewed. Ignition-relevant areal densities of ∼200 mg/cm<superscript>2</superscript> in cryogenic D<subscript>2</subscript> implosions with peak laser-drive intensities of ∼5×10<superscript>14</superscript> W/cm<superscript>2</superscript> were previously reported [T. C. Sangster et al., Phys. Rev. Lett. 100, 185006 (2008)]. The laser intensity is increased to ∼10<superscript>15</superscript> W/cm<superscript>2</superscript> to demonstrate ignition-relevant implosion velocities of 3–4×10<superscript>7</superscript> cm/s, providing an understanding of the relevant target physics. Planar-target acceleration experiments show the importance of the nonlocal electron-thermal-transport effects for modeling the laser drive. Nonlocal and hot-electron preheat is observed to stabilize the Rayleigh–Taylor growth at a peak drive intensity of ∼10<superscript>15</superscript> W/cm<superscript>2</superscript>. The shell preheat caused by hot electrons generated by two-plasmon-decay instability was reduced by using Si-doped ablators. The measured compressibility of planar plastic targets driven with high-compression shaped pulses agrees well with one-dimensional simulations at these intensities. Shock mistiming has contributed to compression degradation of recent cryogenic implosions driven with continuous pulses. Multiple-picket (shock-wave) target designs make it possible for a more robust tuning of the shock-wave arrival times. Cryogenic implosions driven with double-picket pulses demonstrate somewhat improved compression performance at a peak drive intensity of ∼10<superscript>15</superscript> W/cm<superscript>2</superscript>. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
1070664X
Volume :
16
Issue :
5
Database :
Complementary Index
Journal :
Physics of Plasmas
Publication Type :
Academic Journal
Accession number :
40637954
Full Text :
https://doi.org/10.1063/1.3078102