Diagnosing radiation drive asymmetry and absorbed energy in ignition Hohlraums using gas-filled capsules
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States)
The shape of the x-ray self-emission image from an imploded inertial confinement fusion capsule has been used to diagnose Hohlraum radiation drive asymmetry [L. J. Suter et al., Phys. Rev. Lett. 73, 2328 (1994); A. Hauer et al., Rev. Sci. Instrum. 66, 672 (1995); A. Hauer et al., Phys. Plasmas 2, 2488 (1995); N. D. Delameter et al., Phys. Plasmas 3, 2022 (1996)]. Timing of neutron yield from the implosion can also be used to diagnose the absorbed radiation drive energy. We propose a set of beryllium capsules filled with gas, rather than layered cryogenic ice, to diagnose asymmetry and absorbed energy in ignition Hohlraums. Capsules with a range of initial shell thickness have a corresponding range of implosion times, allowing sampling of drive conditions throughout an ignition pulse. For example a 12 {mu}m thick shell implodes during the foot of the ignition pulse, sampling the drive up to about 10 ns. For such capsules, the foot pulse is a high-adiabat drive and leads to implosions that are rather robust against instability and mixing. In these capsules, the best time to record images for diagnosing asymmetry may be several hundred picoseconds after peak x-ray brightness, when the image distortion is increasing rapidly.
- OSTI ID:
- 20861241
- Journal Information:
- Review of Scientific Instruments, Vol. 77, Issue 10; Other Information: DOI: 10.1063/1.2221930; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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