Studies of plastic-ablator compressibility for direct-drive inertial confinement fusion on OMEGA.
The compression of planar plastic targets was studied with x-ray radiography in the range of laser intensities of I approximately 0.5 to 1.5x10(15) W/cm2 using square (low-compression) and shaped (high-compression) pulses. Two-dimensional simulations with the radiative hydrocode DRACO show good agreement with measurements at laser intensities up to I approximately 10(15) W/cm2. These results provide the first experimental evidence for low-entropy, adiabatic compression of plastic shells in the laser intensity regime relevant to direct-drive inertial confinement fusion. A density reduction near the end of the drive at a high intensity of I approximately 1.5x10(15) W/cm2 has been correlated with the hard x-ray signal caused by hot electrons from two-plasmon-decay instability.
Hu
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Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299, USA. shu@lle.rochester.edu
Smalyuk
V A
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Goncharov
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Knauer
J P
JP
Radha
P B
PB
Igumenshchev
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Marozas
J A
JA
Stoeckl
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C
Yaakobi
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B
Shvarts
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Sangster
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McKenty
P W
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Meyerhofer
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DD
Skupsky
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S
McCrory
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RL