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Divertor thermal load is one of the significant problems for a tokamak fusion device, and reduction of the thermal load is required. An application of a Cusp-Type Direct Energy Converter (CuspDEC), which is the device for D-3He fusion power generation to separate charged particles and convert their energy directly into electricity, was proposed to mitigate the heat flux of the divertor plasma. In order to install the CuspDEC in the narrow divertor region, a small-size CuspDEC simulator equipped with permanent magnets (PM-CuspDEC) was constructed to demonstrate divertor simulation experiment in GAMMA 10/PDX, and the performance of charge separation was examined. On one hand, development of measurement technology of heat quantity was also researched. A new calorimeter (CM) made for suppressing heat transmission has newly been manufactured to measure the small energy of end-loss flux in GAMMA 10/PDX experiment. The CM consists of a copper plate and thermocouples and can measure heat quantity and an inflow current simultaneously. The composed new CM is installed in the PM-CuspDEC, and its performance is investigated. A helium ion is used in the experiment of measuring heat quantity. The CM has successfully worked and measured the slight variation of the temperature.

In D-3He fusion, most of fusion energy is carried by created protons as kinetic energy, so direct energy conversion can be applied. A traveling wave direct energy converter was proposed as an energy recovering system for these protons, which was composed of a modulator and a decelerator. The axial position of the decelerator is one of the important device parameters for both energy conversion efficiency and device size. The best position for conversion efficiency was considered to be the bunching position at which proton density is the highest, but it was not examined well. In this study, we investigated the dependence of deceleration efficiency on the axial position of the decelerator by using simulation experiments and numerical calculations. The results show that the bunching position is not necessarily the optimum one for conversion efficiency.