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The “v p ×B” effect is introduced into a traveling wave amplifier trying to increase its output power and efficiency. The numerical calculating results show that by introducing an tapered static magnetic field into a traditional traveling wave amplifier, its output power and efficiency can be increased obviously comparing with an ordinary traveling wave amplifier, because of the effective interactive duration of electron bunches and a rf field is extended by the “v p ×B” effect.

The radiation from the interaction between the ultra‐short andultra‐high power laser(0.5 TW, 100 fs)and the weakly magnetized plasmais studied. We observed the short pulse radiation (200 ps) in themicrowave region(up to 100 GHz). Two kind of radiations whose frequenciesare much lower than the plasma frequency, are observed. One isin the higer frequency region and polarized in parallel to theexternal B field(up to 6 kG). The frequency doesnt depend on the thestrength of the B field. On the other hand, other componets of theemitted radiation is vertically polarized and its frequency depends onthe strength of the B field. The experimental results suggest that theformer radiation is generated by the electron oscillation along the Bfield and the latter is by the electron Bernstein mode.

The peak power of 30 TW and the pulse width of 1 ps produced by the Nd:glass laser system is capable of creating a highly-ionized plasma of a moderate density gas on an ultrafast time scale and generating a large amplitude plasma wave with an accelerating gradient of the order of GeV/m. We are going to demonstrate particle acceleration, injecting electrons of a few MeV emitted from a solid target by intense laser irradiation. >

A collinear wakefield test facility using two linacs with a common test section is constructed. Beams from one linac excite wakefields in a test medium such as a plasma, while beams from the other linac witness the wakefields. The time interval between the two beams is controllable with an accuracy of /spl sim/1 psec. Plasma wakefield acceleration and plasma lens experiments were conducted using this facility. >

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.

A high-power magnetically insulated ion diode with radial geometry was successfully operated on a Reiden IV-H (2 MV, 200 kA) coaxial pulse power machine with across-current feed converter. The generated proton beams were focused ballistically onto the axis. Data of the beam trajectory measurements showed a large aberration of beam focusing in the diode gap region. This may be due to the electron virtual cathode distortion. The reduction of beam focusability was improved simply by correcting the shape of the anode surface. The focused beam intensity of 3×10 10 W/ cm 2 , which was measured by an ion pinhole camera, was compared with predicted values from the trajectory measurements and the beam brightness. Focus reduction factors in the diode were improved from 0.15 to 0.41.

Recent progress of inertial confinement fusion (ICF) research make possible to achieving the ignition condition of pellet implosion in near future. The small target implosion experiments have been done successfully by high power lasers as Gekko XII grass laser system.1 The scaling low of implosion fusion experiments indicates that the several MJ energy driver will realize the ICF reactor. The light ion beam generated by the pulse power technology is the promissing energy driver for ICF due to its high generation efficiency and easy to generate the large energy beam with relatively low cost.