As a numerical calculation technique of the electrostatically induced electric field in the human body by the commercial frequency AC electric field, we propose a two-step process method that employs the voxel-based surface charge simulation method, combined with the fast multipole method (FMM). The validity of the proposed method was verified through analysis of the half spheroid model and the NICT TARO model and the calculation performance, such as error rate, speed, required amount of memory, and parallelization efficiency were investigated. In order to verify the performance of the FMM in this problem, we analyzed the induced fields in simple subdivision models of the TARO model with up to 1.1 billion surface elements (= the number of unknowns N) that correspond to 27.6 billion tissue voxels. The O (N) characteristics of the FMM were successfully confirmed. Therefore, the proposed method can be considered as a useful option even when dealing with large-scale voxel models that are greater than the TARO model.

The authors were able to generate a penetrated water tree in an extruded three layer (E-E type) 6.6 kV XLPE cable subjected to an accelerated water-treeing test, and measured DC leakage and AC superposition currents of the cable. In this study, the penetrated water tree was modeled and DC leakage and AC superposition currents were calculated by using transient electric field analysis, and the calculated currents and measured ones were compared. In addition, the conductivity of water trees was selected so that the calculated AC superposition current was equivalent to the average value of the measured values, and DC leakage and AC superposition currents were calculated for a non-bridged water tree obtained after the accelerated water-treeing test. Furthermore, the shapes of water trees were assumed as spheroidal ones, and the DC leakage current, AC superposition current and AC breakdown voltage were analyzed when the length and width of the water tree changed.

The seasonal behavior of one-dimensional periodic structure is validated. The structure has angular dependence of reflectivity that changes from high reflectivity for summer to low reflectivity for winter. Sunlight simulator is used for exposing the one-dimensional periodic structure and non-structured surface to measure the substrate temperature while changing the angle of incidence from 0 degree to 70 degree. As a result, maximum temperature difference of these structures is achieved where 1.2°C at an angle of incidence of 40 degree.

We developed a new Doppler probe array with two pairs of view-lines to measure 1D ion flow vector. Using this array, just two glass tube insertion enables us to measure 1D ion flow and temperature profile. By use of four mirrors for one measurement point, the system receives the emission of ion in four different directions and that enables us to measure local ion flow vector. It is useful for ion outflow measurement caused by magnetic reconnection.

Surface materials of spacecraft operated in low and medium earth orbits, such as positioning satellite and earth observation satellite, are charged and discharged duet to radio-active rays, such as electrons and protons. Such the electro-static discharge is one of the origin of satellite operation anomaly. Therefore, in this study, we focus the FEP (fluorinated-ethylene-propylene copolymer) irradiated by proton and measure the space charge distribution using newly developed on-site space charge measurement system which can measure space charge accumulation during proton irradiation. We were able to get the result that positive charges were accumulated and saturated during irradiation. After saturation, the accumulated positive charges in the bulk were decreased during irradiation.

DC conduction current and space charge characteristics of laminate elastomer sheets with different laminating directions are investigated. Samples (N,V, H) were prepared as 3 types of the laminate elastomer sheets with different laminating directions using stereolithographic 3D printer. Sample N has no lamination. Sample V has the vertical laminating directions against the sample surface. Sample H has the horizontal laminating direction against sample surface. The sample thickness was around 0.5 mm and the laminating pitch was 0.05mm. The DC conduction current was measured by using current integration meter. Space charge distribution was measured using the pulsed electro-acoustic system. The experiments were carried out at 27°C. The accumulated positive charge amount near anode in sample H was larger than that in V and N. The conductivity was almost field-independent up to around 5kV/mm, but above 5kV/mm it increases with increase of electric field irrespective of difference among samples. It is considered that the conductivity of laminate elastomer sheets is governed by the same basic mechanism and parameter values regardless of space charge accumulation and laminating directions, albeit with slightly different magnitudes.