Laser and Particle Beams (1987), vol. 5, part 4, pp. 609-642 609 Printed in Northern Ireland Results on light ion beam studies for inertial confinement fusion at the Institute of Laser Energetics By K. IMASAKI, S. MIYAMOTO, N. YUGAMI, T. AKIBA, S. SAWADA, K. EMURA, Y. MIZUGUCHI, K. SHIMOURA, K. NISHIHARA, T. OZAKI*, S. NAKAI, AND C. YAMANAKA Recent progress in research on Light Ion Beams-Inertial Confinement Fusion (LIB-ICF) at ILE, Osaka University is summarized. We report on pulsed power compression using PEOS, a super high voltage source, on diode physics, on beam trajectory control for focusing, on beam-target interactions and on a conceptual reactor design (Rokko I) in this article. 1. Introduction The first major milestone for inertial confinement fusion (ICF) research is to achieve ignition. This may be achieved by a laserdriver or by a light ion beam (LIB). Required parameters to achieve ignition using the LIB approach depends on the beam species, energies, brightness, power and the target design. The next step after ignition will be to construct a test facility to study reactor concepts. The LIB also has a reasonable potential for selection as the energy driver of the reactor. From this point of view, we have studied the reactor concept with emphasis on the window of beam transport in the reactor cavity, and the overlap and the coupling with the target at the end of the plasma channel. Research on LIB physics has been performed at ILE, Osaka University based on experiments using the Reiden IV facility. The output from the pulse forming line is 1 MV and 1 MA with a 60 ns pulse length. The voltage of this device is increased to 2-6 times the output of the PFL through the impedance transforming line. Using a plasma opening switch, the output is 6-4 MV on the anode. The brightness of the proton beam approaches 1-6 x 10 14 W/cm 2 rad 2 (Imasaki et al. 1984a). Beam focusing and interac- tion experiments are underway using the high brightness diode. Preliminary studies of a LIB-ICF reactor, Rokko, have been performed. It was found that conditions allow efficient transport of the beam in the reactor cavity. Also, numerical analysis indicated that coupling of the beam to the target at the end of the transport channel is favorable. 2. Requirements for ignition by light ion beam The energy balance and mass conservation equations provide a rough estimate of the driver energy required for the ignition (Imasaki et al. 1984b): £ ig - 4 x 10 9 (l + AJU'J) V ~ V 2 - (1) Here A is the initial nonuniformity of the implosion, n is the final compression ratio normalized by the liquid D-T fuel density, and r\, is an implosion efficiency. In this case, to achieve ignition, values of pR and temperature of 0-4g/cm 2 and 4keV, respectively, were assumed. 0263-0364/87/0504-0609S05.00