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H. Nishimura, H. Azechi, K. Fujita, M. Heya,
R. Ishizaki1, N. Izumi, N. Miyanaga,
M. Murakami, M. Nakai, S. Nakai, M. Nakatsuka,
M. Nishikino, K. Nishihara, T. Norimatsu, Y. Ochi,
N. Ohnishi, K. Shigemori, H. Shiraga, H. Takabe,
T. Yamanaka, C. Yamanaka2, and K. Mima
Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka,
Suita, Osaka 565-0871, Japan
1 National Institute for Fusion Science, 322-6 Shimoishi-cho, Toki, Gifu
509-5292, Japan
2 Institute for Laser Technology, 1-8-4 Utsubohonmachi, Nishi-ku,
Osaka 550-0004, Japan
Abstract. A new fusion-capsule drive-scheme was investigated. The capsule is
illuminated by an low-intensity thermal x-ray pulse in prior to the main
drive pulse, which leads to noticeable suppression of initial imprinting,
brought by the drive beam, due to thermal smoothing in the preformed plasma.
Among several types of the indirect-direct hybrid targets, we investigated
the indirect-direct hybrid effect for two types: One is a foam-hybrid in
which the capsule has a low-density foam layer attached directly on its
surface and pulsed radiation generated with a thin high Z layer on the foam
propagates through the foam, creating a preformed plasma. The other is an
external-hybrid in which the capsule is illuminated, apart from the capsule,
by external x-ray radiation generated with different beams from the capsule
drive beams. The hybrid effect was demonstrated by imposing initial imprint
on a planar target with an intensity modulated beam and subsequent
nonuniformity growth due to Rayleigh-Taylor instability was observed by
face-on back-lighting. The observed suppression due to presence of the
preformed plasma is interpreted by the cloudy-day model for both hybrids.
Capsule implosion experiments have been also started. Overall implosion
dynamics observed is replicated by 1D hydrocode simulations. Preliminary
results form the implosion experiments are presented.
IAEA 2001
