The tungsten vapour produced from the electrodes during short arc lamp operation is transported by gas convection and then deposited on the inner quartz bulb wall to form a tungsten thin film, causing the wall to blacken. We have been able to consider important phenomena for the first time by developing a unified numerical simulation model incorporating relevant sub-models. These include the absorption of the radiant energy due to blackening of the lamp and the temporal variation in the lamp parameters. The validity of the numerical simulation model is first evaluated by comparison with experimental results. The basic characteristics of the lamp obtained using the model is found to be in good agreement with the experimental results and other research results. The influence of the bulb wall blackening is then examined. The temperature of the bulb is shown strongly affected by convective heat transfer from the hot gas, and the temperature rise of the bulb after blackening is found to be primarily governed by the absorption of the radiant energy by the tungsten thin film. Through the increase in the bulb temperature, the gas temperature in the bulb is also increased. This raises the operating pressure, which increases the stress on the bulb wall. Consequently, it is demonstrated that the probability of breakage gradually increases with time due to the blackening by tungsten vapour deposition.

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A new technology for obtaining nanostructure on silicon surface for potential applications to optical devices is represented. Scanning electron microscope analysis indicated a grown nanostructure of dense forest consisting of long cylindrical needle cones with a length of approximately 300 nm and a mutual distance of approximately 200 nm. Raman spectroscopy and spectrophotometry showed a good crystallinity and photon trapping, and reduced light reflectance after helium plasma exposure. The present technique consists of a simple maskless process that circumvents the use of chemical etching liquid, and utilizes soft ion bombardment on silicon substrate, keeping a good crystallinity.

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Microwrinkle structures with a pitch of less than 100 nm and up to 600 nm on refractory metals like tungsten (W) and molybdenum, which are irradiated by noble gas ions such as neon and helium, have been studied systematically. The wrinkle formation mechanism is thought to be a buckling of the hard surface layer supported by the soft elastic substrate, which is induced by a penetration of noble gas species from the irradiated surface. Microwrinkle forms on this structure under lateral compressive strain/stress fields coming from thermal constriction on the way to substrate cooling. Such a process should be anticipated when walls in a fusion reactor are attacked by heat pulses such as edge localized modes and/or vertical displacement events, and therefore might be an initial stage of W surface damage.