Toward Realization of Hypervelocities for Impact Fusion Ignition

Toward Realization of Hyper-velocities for Impact Fusion Ignition (I F I) Nucl. Instrum. & Meth. in Phys. Res. A 544 (2005) 67 M. Murakami 　　　Institute of Laser Engineering, Osaka University ILE H. Azechi, H. Nagatomo, T. Sakaiya, S. Fujioka, H. Shiraga, M. Nakai, K. Shigemori NRL S. Obenschain, M. Karasik, J. Gardner, J. Bates, D. Colombant, J. Weaver, Y. Aglitskiy Contents of talk ・Introduction to I F I ・ 2 D simulation ・First experiment ・Critical issues

Advantages of Impact Ignition (1) Simple Physics (2) High Gain (3) Low Cost

Gain curves for Impact Ignition Targets

Impact Ignition can be designed in other illumination schemes Laser Direct HIB Indirect Laser Indirect

Shock tube problem to estimate the necessary implosion velocity Impactor Main fuel

More realistic velocities would be 1 -2 x 108 cm/s

Temporal evolution of density profile

1 D Radiation-hydrodynamic simulation shows that hyper velocities ~ 108 cm/s can be achieved under proper conditions.

Experiment Laser: • Gekko/HIPER: t. L = 2. 5 ns (super-Gaussian) l. L = 0. 35 mm IL = 4 x 1014 W/cm 2 Target: 14 - 20 mm, • Br-doped plastic planar target (CHBr) • Polystylen (CH)

High Intensity Plasma Experimental Research (HIPER) HIPER and NIKE are the only facilities that can explore impact ignition Target: CH, CHBr 0 cm th = 50 g n e l l Foca #=3 F e v i t Effec KDP Foot pulse Wavelength: 0. 53 mm (2 w) Energy: 0. 5 k. J Intensity: ~ 1012 W/cm 2 Beam smoothing: PCL Main pulse Wavelength: 0. 35 mm (3 w) Energy: 5 k. J Intensity: ~ 1014 W/cm 2 Beam smoothing: 2 -D SSD

We have observed a maximum velocity, 6 x 107 cm/s, ever achieved

Design Window for Laser and Target Parameters

Kritical issues that should be addressed

Summary (1) Preliminary 2 D simulation in full geometry has achieved key numbers such as V = 108 cm/s, r = 400 g/cm 3, T = 5 ke. V (2) First experiment has demonstrated a maximum velocity, V = 6 x 107 cm/s, ever achieved. (3) Further research is now being programmed under ILE/NRL collaboration toward realization of IFI.