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A pulse power transformer has been designed and tested for pulsed power driven Z-pinch experiments. The transformer has reduced the output impedance of a pulsed power machine ‘‘Reiden IV’’ from 2 to 0.02 Ω. The parasitic inductance at the water/vacuum insulator is minimized by the transformer because of the lower output voltage. Therefore, it is possible to improve liner implosion efficiency. When the liner is impedance matched with the transformer, the efficiency is estimated to be ∼10% according to 0-D calculations of the equation of motion and the circuit equation. In experiments, a high current pulse (∼1 MA) was obtained. This value is twice as high as obtained when no transformer is used. Of key importance in the design of the transformer is the geometry of the secondary coil.

We developed a personal computer based simulation method for the design of high-speed optical communication lines. Qmap is a contour plot of the transmission quality on the line parameter spaces. We applied Q-maps to the optimization of TDM and WDM lines considering the fiber nonlinear effects. In 40 Gbit/s 640 km TDM system, we numerically optimized the dispersion compensation elements, and experimentally observed error free transmission in the wavelength range of 1.2 nm. In WDM systems, we discuss the suppression of inter-channel nonlinear effect by alternative dispersion management scheme and quasi-linear transmission scheme. Our simulation system is connected to the Internet, and can exchange open-source codes and results. This system improve the reliability of the simulation studies. We discuss the simulation-studying environment based on the opensource concept, which enables a self-consistent research process of general scientific studies.

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