Symmetry tuning for ignition capsules via the symcap technique
- Los Alamos National Laboratory, P.O. Box 1663, MS E-526, Los Alamos, New Mexico 87544 (United States)
- Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
Symmetry of an implosion is crucial to get ignition successfully. Several methods of control and measurement of symmetry have been applied on many laser systems with mm size hohlraums and ns pulses. On the National Ignition Facility [Moses et al., Phys. Plasmas 16, 041006 (2009)] we have large hohlraums of cm scale, long drive pulses of 10 s of ns, and a large number of beams with the option to tune their wavelengths. Here we discuss how we used the x-ray self-emission from imploding surrogates to ignition capsules (symcaps) to measure the symmetry of the implosion. We show that symcaps are good surrogates for low order symmetry, though having lower sensitivity to distortions than ignition capsules. We demonstrate the ability to transfer energy between laser beams in a gas-filled hohlraum using wavelength tuning, successfully tuning the lowest order symmetry of the symcaps in different size hohlraums at different laser energies within the specification established by calculations for successful ignition.
- OSTI ID:
- 21537892
- Journal Information:
- Physics of Plasmas, Vol. 18, Issue 5; Other Information: DOI: 10.1063/1.3574504; (c) 2011 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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