(OV/5-1) Recent Progress on FIREX Project and Related Fusion Researches at ILE, Osaka

K. Mima1), H. Azechi1), Y. Inubushi1), Y. Fujimoto1), S. Fujioka1), A. Hata1), T. Johzai1), J. Kawanaka1), T. Matumoto1), N. Miyanaga1), M. Murakami1), H. Nagatomo1), K. Nagai1), M. Nakai1), T. Nakamura1), K. Nishihara1), H. Nishimura1), T. Norimatsu1), T. Sakaiya1), H. Shiraga1), H. Yoshida1), T. Jitsuno1), J. Lu1), Y. Nakata1), K. Sueda1), K. Tsubakimoto1), G. Xu1), A. Iwamoto2), T. Mito2), H. Sakagami2), M. Okamoto2), O. Motojima2), R. Kodama3), K. Kondo3), K.A. Tanaka3), H. Habara3), Y. Nakao4), Y. Sentoku5), A. Sunahara6), T. Taguchi7), T. Kanabe8)
1) Institute of Laser Engineering, Osaka University, Osaka, Japan
2) National Institute for Fusion Science, Toki, Gifu
3) Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
4) Graduate School of Engineering, Kyushu University, Fukuoka, Japan
5) Nevada Tera watt Facility, Reno, Nevada, USA
6) Institute of Laser Technology, Osaka, Japan
7) Setunan University, Neyagawa, Osaka, Japan
8) University of Fukui, Fukui, Japan

Abstract.  In the April of 2003, the FIREX project has started. In the project, the heating laser of 10 kJ/10 ps/1.06 μm, target fabrication and irradiation system of foam cryogenic target, and integrated fast ignition simulation code are developed as the collaboration program between Osaka University, NIFS (National Institute for Fusion Science) and other universities. After the completion of the laser, we will irradiate a foam cryogenic cone shell target with LFEX in late 2007. Cone shell target implosion has been simulated by 2D PINOCO. The shape of imploded core plasma of experiments is well reproduced in the simulation. Namely, the top of the cone is damaged by the jet produced by the stagnation of imploding fuel shell. The PINOCO simulation results also show that the plasma density is as high as the maximum density of spherical implosion and the area density can be higher than the spherical implosion. From the present understanding on the heating physics and the cone shell implosion hydrodynamics, we believe that the area density will reach 0.45 g/cm2 and 1.2 g/cm2 respectively in the FIREX-I, and -II. It is found that implosion of cone target is relatively insensitive to the hydrodynamic instabilities in comparison with spherical target. Planer cryogenic foam layer targets were irradiated with GEKKO XII laser recently. As a result, we found that a deuterium layer is compressed and accelerated by ablation pressure as expected in simulations. We also irradiated a foam cryogenic deuterium layer with the peta watt laser to investigate the heat transport. DD neutron from a cryogenic foam layer target has been observed. The neutron yield of cryogenic target is compared with CD plastic target to find that heat transport is strongly inhibited on a surface of a cryogenic DD layer. As an alternative fast heating scheme, the impact of a highly accelerated foil has been proposed, where the ablative acceleration to the order of 108 cm/sec is the key issue. The recent experiments show that the planer target is accelerated to 8×107 cm/sec. Finally the future scope of the fast ignition laser fusion will be discussed through reactor design.

Full paper and slides available (PDF)