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High-density compression experiments at ILE, Osaka

Published online by Cambridge University Press:  09 March 2009

H. Azechi
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
T. Jitsuno
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
T. Kanabe
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
M. Katayama
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
K. Mima
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
N. Miyanaga
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
M. Nakai
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
S. Nakai
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
H. Nakaishi
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
M. Nakatsuka
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
A. Nishiguchi
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
P. A. Norrays
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
Y. Setsuhara
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
M. Takagi
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
M. Yamanaka
Affiliation:
Institute of Laser Engineering, Osaka University, 2–6 Yamada-oka, Suita, Osaka 565, Japan
C. Yamanaka
Affiliation:
Institute for Laser Technology, Suita, Osaka 565, Japan

Abstract

Direct-drive implosion experiments on the GEKKO XII laser (9 kJ, 0.5 μm, 2 ns) with deuterium and tritium (DT) exchanged plastic hollow shell targets demonstrated fuel areal densities (ρR) of ˜0.1 g/cm2 and fuel densities of ˜600 times liquid density at fuel temperatures of ˜0.3 keV. (The density and ρR values refer only to DT and do not include carbons in the plastic targets.) These values are to be compared with thermonuclear ignition conditions, i.e., fuel densities of 500–1000 times liquid density, fuel areal densities greater than 0.3 g/cm2, and fuel temperatures greater than 5 keV. The irradiation nonuniformity in these experiments was significantly reduced to a level of <5% in root mean square by introducing random-phase plates. The target irregularity was controlled to a 1% level. The fuel ρR was directly measured with the neutron activation of Si, which was originally compounded in the plastic targets. The fuel densities were estimated from the ρR values using the mass conservation relation, where the ablated mass was separately measured using the time-dependent X-ray emission from multilayer targets. Although the observed densities were in agreement with one-dimensional calculation results with convergence ratios of 25–30, the observed neutron yields were significantly lower than those of the calculations. This suggests the implosion uniformity is not sufficient to create a hot spark in which most neutrons should be generated.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1991

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References

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