Two-plasmon-decay instability in direct-drive inertial confinement fusion experiments
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)
- Department of Applied Science, University of California at Davis, California 95616 (United States)
The two-plasmon-decay (TPD) instability in direct-drive irradiation OMEGA [J. M. Soures, R. L. McCrory, C. P. Verdon, et al., Phys. Plasmas 3, 2108 (1996)] experiments is seen in the half-integer harmonic emission. Experimental time-resolved {omega}/2 and 3{omega}/2 spectra indicate that the linear theory for the absolute TPD instability reasonably predicts TPD thresholds. The plasma wave spectra do not, however, agree at all with the predictions of the linear theory. This is most likely a consequence of the nonlinear evolution of this instability once it is above threshold. This is demonstrated with spectral data obtained from spherical implosion experiments as well as planar target experiments. In the latter, Thomson scattering shows the importance of the Landau cutoff. For the TPD instability, the Landau cutoff is found to be respected in all spherical and planar target experiments. In addition, the maximum plasma wave amplitudes appear to occur near the Landau cutoff.
- OSTI ID:
- 21277098
- Journal Information:
- Physics of Plasmas, Vol. 16, Issue 5; Other Information: DOI: 10.1063/1.3125242; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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