Ryusuke Tsuji

Fabrication of polystyrene hollow pellet with high Z microparticles on inner surface for measurement of temperature and density in ICF plasma

Copyright (c) 1997 Elsevier Science S.A. All rights reserved. A new type of polystyrene hollow pellet is fabricated for inertial confinement fusion (ICF) experiments. The pellet adsorbs high Z microparticles on its inner surface to emit characteristic X-rays of the high Z material. The fabrication method uses emulsion techniques. Three different phases of solution (W, W, O) are used for the fabrication process. The W phase is a 1 wt.% high Z microparticle mixture in water. This W phase solution is mixed with a 10 wt.% polystyrene solution in dichloromethane (O phase) while stirring. The resulting emulsion (W/O) is then poured into a 0.5 wt.% aqueous gelatin solution (W phase) while stirring. The resulting emulsion ((W/O)/W) is heated to evaporate dichloromethane and a solid polystyrene shell is formed. After drying, water which is encapsulated in the shell evaporates out and high Z microparticles remain on the inner surface of the pellet.

Position Measurement Method Using a Divergent Laser Beam and Arago Spot for Tracking of an Inertial Fusion Energy Target

This paper is a complement to our previous work [Jpn. J. Appl. Phys. 46 (2007) 6000] on the accuracy of the position measurement method using an Arago spot for an inertial fusion energy target tracking system and we here report an improvement of the measurement accuracy using a divergent laser beam. By employing divergent beam illumination, we can magnify the displacement of the Arago spot compared with the actual displacement of the target without enlarging the diameter of the Arago spot significantly, allowing us to measure the small displacement of the target with high accuracy over a large measurement range. The experimental results for a 5-mm-diameter target demonstrated that a measurement accuracy of lower than 0.2 µm can be achieved when the distance between the target and a charge-coupled device camera is within the range from 2 to 10 m.

Accuracy of Position Measurement Method Using Arago Spot for Inertial Fusion Energy Target Tracking System

The accuracy of a position measurement method using the Arago spot is reported for an inertial fusion energy (IFE) target tracking system, where the position of the target is determined by the position of the Arago spot, which is a bright spot appearing in the central portion of the diffraction pattern of a spherical obstacle. We use a He–Ne laser as the light source and a charge-coupled device (CCD) camera with a microscope objective lens to magnify and record the diffraction pattern of a spherical target. We examine two different algorithms to determine the center of the Arago spot in order to compare the measurement performances. The experimental results show that the position of a 5-mm-diameter target can be obtained with a measurement resolution of 1 µm and an rms measurement error of less than 0.2 µm for both algorithms when the distance between the target and the microscope objective lens is 5 cm.

Diagnostics for liquid samples by laser-pumped photo-thermal method

A laser pumped-thermal lens system as a tool for the measurement of liquid samples was constructed. The clear distinction of three different liquids at the stationary state was demonstrated. An example of the time-course feature at the transient state of diffusion when an impurity droplet was dropped into water was traced, exhibiting a time of about 5 s to the end of diffusion. The intensity of thermal lens signal versus the mixing rate of liquid samples in water at the steady state was measured with good reproducibility.

Parallel computing for tracing torus magnetic field line

This paper introduces a simple and approximate method of calculating the intersections on the cross section of the torus crossed by a torus magnetic field line which is added by a weak perturbed field. The method is based on consideration of the interpolation of the values of transition tables of the position of starting points and arrival points of magnetic field lines. A simplified geometry model is used to clarify the idea of the method. The calculation program is parallelized to implement on a HITACHI SR-2201 parallel computer to reduce the calculation time. Some numerical results are presented.

Computation of Poincare map of chaotic torus magnetic field line using parallel computation of data table and its interpolation

This paper describes computational methods of a Poincare map using parallel computation of data tables and interpolation. The Poincare map of a chaotic torus magnetic field line caused by the perturbation coil is calculated as the test problem. Data tables are made by the geometric parallelization method. The calculation program is implemented on the HITACHI SR2201 parallel computer and microcomputers. Two calculation methods using data tables are presented. Calculation time of making data tables and the Poincare map is reported.

Transmissivities of Radiation Beams and Particle Beams in Multicomponent Mixed Materials: II. Finite Markov Chain Model

This paper is a complement to an earlier paper [Jpn. J. Appl. Phys. 35 (1996) 4793] on the transmissivity of beams in multicomponent mixed materials of identical grain size and presents an analytical expression of transmissivity based on the finite Markov chain in the case of mixed materials of different grain sizes. The expression is represented by the flux vector and the response matrix obtained from the transition matrix.