Triple-picket warm plastic-shell implosions on OMEGA

Journal Article · Sat Jan 15 00:00:00 EST 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3544930· OSTI ID:21532181

Radha, P B; Stoeckl, C; Goncharov, V N; Delettrez, J A; Edgell, D H; Igumenshchev, I V; Knauer, J P; Marozas, J A; Regan, S P; Sangster, T C; Seka, W; Skupsky, S ^[1]; Frenje, J A ^[2]; McCrory, R L; Meyerhofer, D D ^[1]; Petrasso, R D ^[3]

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1. Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)
2. Plasma Fusion Science Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States)
3. Department of Mechanical Engineering and Department of Physics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)

Warm deuterium-gas-filled plastic shells are imploded by direct irradiation from the OMEGA laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. The pulse shapes contain three pickets that precede a sharp rise to a constant laser intensity at {approx}4.5x10{sup 14} W/cm{sup 2}. The in-flight-aspect-ratio (IFAR), a crucial measure of shell instability to nonuniformity growth, is varied in these implosions by changing picket energies and the timing among the pickets. Simulations that include cross-beam energy transfer in addition to inverse bremsstrahlung for the laser-energy deposition models show better agreement with measurements of the neutron bang time and temporally resolved scattered light and therefore more correctly model the shell kinetic energy. It is also shown that target performance improves significantly as IFAR is reduced. Nearly twice the neutron yield is measured for IFAR{approx}31 compared to IFAR{approx}60. The ratio of the measured to simulated neutron yield and areal density increases significantly with decreasing IFAR. These implosions unambiguously link target performance to in-flight shell instability attributable to short-wavelength growth and indicate that IFAR{<=}40 is required to achieve adequate compression at this intensity.

• OSTI ID: 21532181
• Journal Information: Physics of Plasmas, Vol. 18, Issue 1; Other Information: DOI: 10.1063/1.3544930; (c) 2011 American Institute of Physics; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ENERGY TRANSFER
IMPLOSIONS
LASERS
PLASMA DENSITY
PLASMA INSTABILITY
PLASMA SIMULATION
INSTABILITY
SIMULATION