Impact of imposed mode 2 laser drive asymmetry on inertial confinement fusion implosions

Dataset · Mon Mar 18 00:00:00 EDT 2019

DOI:https://doi.org/10.7910/DVN/6E9ONS· OSTI ID:1881326

Johnson, M. Gatu; Appelbe, B. D.; Chittenden, J. P.; Crilly, A.; Delettrez, J.; Forrest, C.; Frenje, J. A.; Glebov, V. Yu.; Grimble, W.; Haines, B. M.; Igumenshchev, I.; Janezic, R.; Knauer, J. P.; Lahmann, B.; Marshall, F. J.; Michel, T.; Séguin, F. H.; Stoeckl, C.; Walsh, C.; Zylstra, A. B. ; Petrasso, R. D.

Low-mode asymmetries have emerged as one of the primary challenges to achieving high-performing inertial confinement fusion implosions. These asymmetries seed flows in the implosions, which will manifest as modifications to the measured ion temperature (Tion) as inferred from the broadening of primary neutron spectra. The effects are important to understand both to learn to control and mitigate low-mode asymmetries, and to experimentally more closely capture thermal Tion used as input in implosion performance metric calculations. In this paper, results from and simulations of a set of experiments with a seeded mode 2 in the laser drive are described. The goal of this intentionally asymmetrically driven experiment was to test our capability to predict and measure the signatures of flows seeded by the low-mode asymmetry. The results from these experiments (first discussed in M Gatu Johnson et al, Phys. Rev. E 98, 051201(R) (2018)) demonstrate the importance of interplay of flows seeded by various asymmetry seeds. In particular, measured Tion and self-emission x-ray asymmetries are expected to be well captured by interplay between flow seeded by the imposed mode 2 and the capsule stalk mount. Measurements of areal density asymmetry also indicate the importance of the stalk mount as an asymmetry seed in these implosions. The simulations brought to bear on the problem (1D LILAC, 2D xRAGE, 3D ASTER and 3D Chimera) show how thermal Tion is expected to be significantly lower than Tion as inferred from the broadening of measured neutron spectra. They also show that the electron temperature is not expected to be the same as Tion for these implosions.

• Research Organization: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: NA0002949; NA0002726; AC52-06NA25396
• OSTI ID: 1881326
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY