researchmap

researchmap

AP/HTPB composite propellant is the most typical solid propellant that currently used. In order to obtain excellent combustion characteristics and reliability as a solid rocket motor, it is necessary to measure the dispersion state of AP particles and voids in solid propellant. In this study, we propose the measurement method of the mixed degree that represents the dispersion state of AP particles and voids in by using X-ray CT imaging. The mixed state of the AP/HTPB composite propellant is quantified by analyzing the brightness histogram obtained from the CT image. In the brightness histogram, mixed degree shows the difference between the ideal and measured propellant compositions in the image. Solid propellants with different mixing time were scanned by X-ray CT apparatus. The characteristics of the solid propellant at each mixing time were visualized. The mixing degree decreased as the mixing time longer.

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

The two-dimensional (2-D) Horn-antenna Millimeter-wave Imaging Device (HMID) has been developed for the O-mode Microwave Imaging Reflectometry (O-MIR) in the Large Helical Device (LHD). The detectable frequency range of the HMID is 23-33 GHz, which corresponds to the cutoff electron density of 0.8-1.5 X 10(19) m(-3) in the O-MIR. The HMID is a 2-D imaging device that improves on the horn-antenna mixer array, which had been developed for the X-mode MIR in the LHD. In the HMID, the signal (RF) wave from the horn antenna is transmitted to the microstrip line by the finline transmitter, and this is mixed by the double-balanced-mixer with the local oscillation wave that is fed by a coaxial cable. By using the HMID, the MIR optical system can be significantly simplified. Published by AIP Publishing.

DOI： 10.1063/1.4980150

Web of Science

researchmap

researchmap

researchmap

researchmap

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Plasma Science and Nuclear Fusion Research  

The O-mode microwave imaging reflectometry (O-MIR) has been developed. The frequency is 26 - 34 GHz, which corresponds to the cutoff electron density of 0.8 - 1.5 � 1019 m-3. Since the local wave of the newly developed horn antenna millimeter wave imaging device (HMID) is fed by coaxial cable, the optical system of O-MIR is significantly simplified. By using O-MIR, the edge electron density fluctuation in an H-mode plasma is observed in LHD. The spectrum in the wave number and the frequency (k -ω) space is obtained by using the two-point correlation analysis. In the H-mode plasma the fluctuation amplitude is higher and the k -ω spectrum has the feature of the drift wave.

DOI： 10.1585/pfr.11.2402111

Scopus

researchmap

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

Microwave imaging diagnostics are powerful tools that are used to obtain details of complex structures and behaviors of such systems as magnetically confined plasmas. For example, microwave imaging reflectometry and microwave imaging interferometers are suitable for observing phenomena that are involved with electron density fluctuations; moreover, electron cyclotron emission imaging diagnostics enable us to accomplish the significant task of observing MHD instabilities in large tokamaks. However, microwave imaging systems include difficulties in terms of multi-channelization and cost. Recently, we solved these problems by developing a Horn-antenna Mixer Array (HMA), a 50 - 110 GHz 1-D heterodyne-type antenna array, which can be easily stacked as a 2-D receiving array, because it uses an end-fire element. However, the HMA still evidenced problems owing to the requirement for local oscillation (LO) optics and an expensive high-power LO source. To solve this problem, we have developed an upgraded HMA, named the Local Integrated Antenna array (LIA), in which each channel has an internal LO supply using a frequency multiplier integrated circuit. Therefore, the proposed antenna array eliminates the need for both the LO optics and the high-power LO source. This paper describes the principle of the LIA, and provides details about an 8 channel prototype LIA.

DOI： 10.1088/1748-0221/10/12/C12031

Web of Science

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

A new antenna array is proposed in order to improve the sensitivity and complexity of microwave imaging diagnostics systems such as a microwave imaging reflectometry, a microwave imaging interferometer, and an electron cyclotron emission imaging. The antenna array consists of five elements: a horn antenna, a waveguide-to-microstrip line transition, a mixer, a local oscillation (LO) module, and an intermediate frequency amplifier. By using an LO module, the LO optics can be removed, and the supplied LO power to each element can be equalized. We report details of the antenna array and characteristics of a prototype antenna array. (C) 2014 AIP Publishing LLC.

DOI： 10.1063/1.4885471

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

A compact Cherenkov free-electron laser operating in the terahertz spectral range is being developed. Analysis of the double-slab type optical resonator has clarified the resonant frequency, the small signal gain, and the saturation power of the device. One-dimensional simulation code predicted a small signal gain of 6% with a 50 kV/3.6 mA electron beam. The saturation power was estimated to be 90 mW. The out-coupling structure of the resonator was designed using 3D simulation code. A transmittivity of 3.0% and a spread angle of 0.4 rad were predicted.

DOI： 10.1002/ecj.11554

Web of Science

researchmap

Language：Japanese   Publisher：The Institute of Electrical Engineers of Japan  

Developments of two types of the electron gun are presented. One is a compact DC electron gun using Field Emitter Array (FEA) as the <i>cold</i> cathode, the other is a photoinjector which outputs sub-pico second electron beam pulse. The FEA electron gun achieved to producing a 2 mA/50 kV electron beam. The photoinjector experiments revealed an exotic space-charge effect on the ultra-shot electron beam pulse.

DOI： 10.1541/ieejfms.134.22

CiNii Books

researchmap

Other Link： https://jlc.jst.go.jp/DN/JALC/10027425656?from=CiNii

researchmap

Publishing type：Research paper (international conference proceedings)  

researchmap

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

Progress in microwave and millimeter-wave technologies has made possible advanced diagnostics for application to various fields, such as, plasma diagnostics, radio astronomy, alien substance detection, airborne and spaceborne imaging radars called as synthetic aperture radars, living body measurements. Transmission, reflection, scattering, and radiation processes of electromagnetic waves are utilized as diagnostic tools. In this report we focus on the reflectometric measurements and applications to biological signals (vital signal detection and breast cancer detection) as well as plasma diagnostics, specifically by use of imaging technique and ultra-wideband radar technique.

DOI： 10.1088/1748-0221/7/01/C01089

Web of Science

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

Turbulence in the reversed field pinch (RFP) plasma has been investigated by using the microwave imaging reflectometry in the toroidal pinch experiment RX (TPE-RX). In conventional RFP plasma, the fluctuations are dominated by the intermittent blob-like structures. These structures are accompanied with the generation of magnetic field, the strong turbulence, and high nonlinear coupling among the high and low k modes. The pulsed poloidal current drive operation, which improves the plasma confinement significantly, suppresses the dynamo, the turbulence, and the blob-like structures. (C) 2011 American Institute of Physics. [doi:10.1063/1.3652848]

DOI： 10.1063/1.3652848

Web of Science

researchmap

researchmap

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：WORLD SCIENTIFIC PUBL CO PTE LTD  

Microwave imaging reflectometry (MIR) system and electron cyclotron emission imaging (ECEI) system are under development for the simultaneous reconstruction of the electron density and temperature fluctuation structures in the Large Helical Device (LHD). The MIR observes three-dimensional structure of disturbed cutoff surfaces by using the two-dimensionally distributed horn-antenna mixer array (HMA) of 5 x 7 channels in combination with the simultaneous projection of microwaves with four different frequency components (60.410, 61.808, 63.008 and 64.610 GHz). The ECEI is designed to observe two-dimensional structure of electron temperature by detecting second-harmonic ECE at 97-107 GHz with the one-dimensional HMA (7 channels) in the common optics with MIR system. Both the MIR and the ECEI are realized by the HMA and the band-pass filter (BPF) arrays, which are fabricated by micro strip-line technique at low-cost.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Experimental investigation of a compact 40-kV diode-type photoelectric DC gun driven by 100fs laser pulses revealed that the space-charge-limited current density could exceed 30kA/cm2 and that the density increased linearly with the accelerating voltage. We explained these important properties by the balance between the cathode surface field and the field produced by sheet-like electron bunches near the cathode surface. Our simple physical model agreed well with the experimental results. Copyright © 2011 Hiroko Yamamoto et al.

DOI： 10.1155/2011/714265

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

A simultaneous projection/detection system of four different frequencies for microwave imaging reflectometry (MIR) was developed for three-dimensional observation of electron density fluctuations in the Large Helical Device (LHD). The microwave with four frequency components at 60.410, 61.808, 63.008, and 64.610 GHz is projected in a continuous-wave mode to illuminate the target LHD plasma. A two-dimensional horn-antenna mixer array (2D HMA) receives the reflected wave from the plasma as well as the wave from the local oscillator operating at 55.800 GHz. The first intermediate frequency (IF) signals at 4.610, 6.008, 7.208, and 8.810 GHz were confirmed to be obtained by downconversion of these microwaves using the 2D HMA. Each of these first IF components is filtered from each other and downconverted again for the superheterodyne detection. It was confirmed that both the amplitudes and the phases of the detected signals reflect the fluctuations in LHD plasmas. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3491197]

DOI： 10.1063/1.3491197

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

A combined system of microwave imaging reflectometry and electron cyclotron emission (ECE) imaging has been developed for the Large Helical Device. This system includes a wide-band two-dimensional horn-antenna mixer array (HMA). The HMA consists of horn antennas, waveguides, mixers, and intermediate frequency circuits. The frequency response of the HMA is between 50 and 110 GHz. The ECE signal is selected using a 95 GHz local oscillator and a 93 GHz high-pass filter. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3491223]

DOI： 10.1063/1.3491223

Web of Science

researchmap

researchmap

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER NUCLEAR SOC  

Several types of microwave diagnostics, in the category of electron cyclotron emission (ECE) spectroscopy and reflectometry, have been developed on the Large Helical Device (LHD). Since LHD has a complicated magnetic configuration, the polarization effects have been studied for optimization of the microwave passive and active diagnostics. It was found that if the density is sufficiently high, the effect of mode conversion is negligible and the local polarization angle can be estimated as the angle at the plasma boundary. Three types of ECE spectroscopy, which are the heterodyne radiometer, the Michelson spectrometer, and the grating polychromator, have been optimized and operated routinely in order to measure radial profiles of electron temperature and its fluctuations in the frequency range 50 to 500 GHz. Several types of microwave reflectometers have also been utilized for measurements of the electron density profile and fluctuations. Two ultrashort pulsed radar reflectometers for density profile measurements, a V-band frequency-hopping reflectometer for density fluctuation profile measurements, and a fixed-frequency three-channel homodyne reflectometer for the interlock system of the neutral beam injection have been routinely operated. Also, an advanced diagnostic, which uses an imaging technique, has been developed to study the two- or three-dimensional structure of temperature and density fluctuations.

Web of Science

researchmap

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

A 50 kV photo-electron gun was developed to construct a powerful broad-band terahertz radiation source. A magnesium photocathode was irradiated by a frequency tripled Ti:sapphire laser. Train of electron bunch of 50 pC was generated. The bunch produced the optical transition radiation at the beam dumper.

Web of Science

researchmap

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

We have developed an electron cyclotron emission (ECE) radiometer to measure the radial electron temperature profiles. Before installation of this system on KSTAR, we installed a part of this system on LHD, and confirmed that acquired signals are in good agreement with those provided by the Michelson spectrometer.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Microwave to millimeter-wave diagnostic techniques such as interferometry, reflectometry, scattering and radiometry have been powerful tools for diagnosing magnetically confined plasmas. Recent advances in electronic devices and components together with computer technology have enabled the development of advanced diagnostics in microwave to millimeter-wave region. The two-dimensional and three-dimensional profiles of plasma density/temperature and dynamic behaviors of their fluctuations are measured by using the advanced diagnostic systems. The measurements have clarified the physics issues such as stability, wave phenomena and fluctuation-induced transport. We report here on the representative microwave diagnostics and their contribution to plasma confinement physics.

DOI： 10.1080/10519990902909436

Web of Science

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

Three key devices of the microwave imaging reflectometry (MIR) are under development in large helical device (LHD). The 2-D mixer array is developed by stacking the one-dimensional array of the planar Yagi-Uda antenna. The new type of the bandpass filter bank is modified to match the requirement of the MIR. The low-cost quadrature demodulator is also developed for the phase detection system. By using the low-price commercial wireless devices, the development cost becomes much lower than the expensive waveguide system. These devices enable the development of 2-D/3-D microwave imaging system for the plasma diagnostics and industrial applications.

DOI： 10.1063/1.2993741

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

Plasma experiments on KSTAR are scheduled to start up this year (2008). We have developed an electron cyclotron emission (ECE) radiometer to measure the radial electron temperature profiles in KSTAR experiments. The radiometer system consists, briefly, of two downconversion stages, amplifiers, bandpass filter banks, and video detectors. These components are made commercially or developed in house. The system detects ECE power in the frequency range from 110 to 196 GHz, the detected signal being resolved by means of 48 frequency windows. Before installation of this system on KSTAR, we installed a part of this system on large helical device (LHD) to study the system under similar plasma conditions. In this experiment, the signal amplitude, considered to be proportional to the electron temperature, is measured. The time-dependent traces of the electron temperature measured by this radiometer are in good agreement with those provided by the LHD Michelson spectrometer. The system noise level which limits the minimum measurable temperature (converted to the electron temperature) is about 30 eV.

DOI： 10.1063/1.2966380

Web of Science

researchmap

researchmap

researchmap

researchmap

researchmap

Language：Japanese  

J-GLOBAL

researchmap

researchmap

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

A multichannel reflectometry with an imaging optical system is under development for the measurement of the electron density fluctuations in the Large Helical Device (LHD). The right-hand cutoff layer is utilized as a reflection surface. The angle of an ellipsoidal mirror installed inside the vacuum chamber is remotely adjustable with the ultrasonic motor in order to optimize the illumination angle for the wider range of the plasma parameters. An oscillation due to density fluctuation was observed using the microwave imaging reflectometry for the first time in LHD plasma experiment. (c) 2006 American Institute of Physics.

DOI： 10.1063/1.2349749

Web of Science

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

This paper presents development of quasi-optical microwave technology for ECE and reflectometry diagnostics in the Large Helical Device (LHD). The ECE for the electron temperature measument is transmitted with the corrugated wave guide system. Technology for Microwave imaging, sucn as imaging reflectometry and ECE imaging, has been developed to visualize 3D view of turbulence.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：INT ATOMIC ENERGY AGENCY  

The main objective of the Low Aspect Ratio Torus Experiment (LATE) device is to demonstrate the formation of spherical torus (ST) plasmas by electron cyclotron heating (ECH) alone without a centre solenoid and establish its physical bases. By injecting a 2.45 GHz microwave pulse for 4 s, a plasma current of 1.2 kA is spontaneously initiated by P = 5 kW under a weak steady vertical field of B-v = 12 G and then ramped up slowly with a slow ramp-up of Bv for the equilibrium of the plasma loop and finally reaches 6.3 kA by P = 30 kW at Bv = 70 G. This current amounts to 10% of the total coil currents of 60 kA flowing through the centre post for the toroidal field. Magnetic measurements show that an ST equilibrium, having the last closed flux surface with an aspect ratio of R-0/a similar or equal to 20.4 cm/14.5 cm similar or equal to 1.4, an elongation of k similar or equal to 1.5 and q(edge) similar or equal to 37, has been produced and maintained for 0.5 s at the final stage of discharge. Spontaneous formation of ST equilibria under steady Bv fields, where plasma current increases rapidly in the time scale of a few milliseconds, is also effective and a plasma current of 6.8 kA is spontaneously generated and maintained at BY = 85 G by a 5 GHz microwave pulse (130 kW, 60 ms). In both cases, the plasma centre locates near the second or third harmonic EC resonance layer and the line averaged electron density significantly exceeds the plasma cutoff density, suggesting that the harmonic EC heating by the mode-converted electron Bernstein waves supports the plasma.

DOI： 10.1088/0029-5515/45/11/026

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：INT ATOMIC ENERGY AGENCY  

The main objective of the Low Aspect Ratio Torus Experiment (LATE) device is to demonstrate the formation of spherical torus (ST) plasmas by electron cyclotron heating (ECH) alone without a centre solenoid and establish its physical bases. By injecting a 2.45 GHz microwave pulse for 4 s, a plasma current of 1.2 kA is spontaneously initiated by P = 5 kW under a weak steady vertical field of B-v = 12 G and then ramped up slowly with a slow ramp-up of Bv for the equilibrium of the plasma loop and finally reaches 6.3 kA by P = 30 kW at Bv = 70 G. This current amounts to 10% of the total coil currents of 60 kA flowing through the centre post for the toroidal field. Magnetic measurements show that an ST equilibrium, having the last closed flux surface with an aspect ratio of R-0/a similar or equal to 20.4 cm/14.5 cm similar or equal to 1.4, an elongation of k similar or equal to 1.5 and q(edge) similar or equal to 37, has been produced and maintained for 0.5 s at the final stage of discharge. Spontaneous formation of ST equilibria under steady Bv fields, where plasma current increases rapidly in the time scale of a few milliseconds, is also effective and a plasma current of 6.8 kA is spontaneously generated and maintained at BY = 85 G by a 5 GHz microwave pulse (130 kW, 60 ms). In both cases, the plasma centre locates near the second or third harmonic EC resonance layer and the line averaged electron density significantly exceeds the plasma cutoff density, suggesting that the harmonic EC heating by the mode-converted electron Bernstein waves supports the plasma.

DOI： 10.1088/0029-5515/45/11/026

Web of Science

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Physical Society of Japan (JPS)  

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Physical Society of Japan (JPS)  

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The main objective of LATE is to demonstrate the formation of Spherical Tokamak (ST) by electron cyclotron heating (ECH) alone without the center solenoid. In the last year, as a result of the extended microwave power from 10 to 30 kW and introducing the vertical plasma position control system, the achievable plasma current has been raised substantially compared with the results reported previously(1). With a two-seconds pulse of 2.45 GHz microwave power up to 30 kW, a plasma current of 2.0 kA have been spontaneously initiated under the steady vertical field, then ramped-up slowly to 7.2 kA with a slow ramp-up of the vertical field strength (Bv) for the equilibrium of the plasma current loop. The Bv decay index is temporally-controlled during the discharge to successfully increase the plasma elongation with the aid of the active control of the vertical plasma position. This increase in elongation has lead to an effective increase in the plasma current. Magnetic analysis shows that an ST equilibrium, having the last closed flux surface with an aspect ratio of R0/a = 20.5cm/14.8cm ≃ 1.4, an elongation of κ ≃ 1.6 and qedge ≃ 34, has been finally formed and maintained steady until the end of the microwave pulse. © 2005, The Institute of Electrical Engineers of Japan. All rights reserved.

DOI： 10.1541/ieejfms.125.914

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

In the LATE device, Spherical Tokamak (ST) plasmas are formed by electron cyclotron heating (ECH) without center solenoid. Two types of experiments are described: (1) slow formation of ST plasmas and (2) spontaneous formation of ST plasmas with rapid-current-rise. A ST formation scenario is discussed including the current-drive mechanism, particle confinement and MHD equilibrium.

Web of Science

researchmap

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The main objective of LATE is to demonstrate the formation of Spherical Tokamak (ST) by electron cyclotron heating (ECH) alone without the center solenoid. In the last year, as a result of the extended microwave power from 10 to 30 kW and introducing the vertical plasma position control system, the achievable plasma current has been raised substantially compared with the results reported previously(1). With a two-seconds pulse of 2.45 GHz microwave power up to 30 kW, a plasma current of 2.0 kA have been spontaneously initiated under the steady vertical field, then ramped-up slowly to 7.2 kA with a slow ramp-up of the vertical field strength (Bv) for the equilibrium of the plasma current loop. The Bv decay index is temporally-controlled during the discharge to successfully increase the plasma elongation with the aid of the active control of the vertical plasma position. This increase in elongation has lead to an effective increase in the plasma current. Magnetic analysis shows that an ST equilibrium, having the last closed flux surface with an aspect ratio of R0/a = 20.5cm/14.8cm ≃ 1.4, an elongation of κ ≃ 1.6 and qedge ≃ 34, has been finally formed and maintained steady until the end of the microwave pulse. © 2005, The Institute of Electrical Engineers of Japan. All rights reserved.

DOI： 10.1541/ieejfms.125.914

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

Sawtooth crashes in an Ohmically heated plasma with a low safety factor of q(a) similar or equal to 2.7 in the WT-3 tokamak have been observed by using soft x-ray computer tomography (SXCT) systems attached at three different poloidal cross sections around the torus. With this multi-toroidally positioned (MTP) SXCT system we have examined how the core plasmas collapse at the three different toroidal locations in terms of the shift and the shape of hot cores in order to visualize the whole helical hot structure around the torus during the crash. A variety of crashes have been observed. In any case collapsing proceeds in two steps, called the first and second phases. In the first phase collapsing proceeds slowly keeping the helical hot structure of an m = 1/n = 1 mode and/or an m = 2/n = 2 mode around the torus. In the second phase, collapsing proceeds rapidly as the helical hot structure is strongly deformed, and reaches the end in such a manner that the hot core shifted to the low field side is deformed into a thin crescent shape aligned along the inversion circle while that shifted to the high field side fades away or is deformed into a broad, warm structure depending on the types of crashes. Thus, present MTP SXCT has revealed for the first time a remarkable deformation of the helical hot structure around the torus during the sawtooth crashes.

DOI： 10.1088/0741-3335/46/8/001

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMERICAN PHYSICAL SOC  

Sawtooth crashes in an Ohmically heated plasma in the WT-3 tokamak have been observed by using soft x-ray computer tomography at three different poloidal cross sections around the torus. Initially, collapsing proceeds slowly with keeping the helical structure of an m=1/n=1 hot core around the torus. It accelerates as the helical hot structure is strongly deformed and fades away in the manner that the hot core at the high field side becomes obscure and disappears, while that at the low field side is deformed into a thin crescent aligned along the inversion circle, which survives even at the completion of the crash.

DOI： 10.1103/PhysRevLett.93.045005

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMERICAN PHYSICAL SOC  

Extraordinary (X) waves are perpendicularly injected for electron Bernstein (B) wave heating into an Ohmically heated plasma from the inboard side in the WT-3 tokamak. Measurements show that absorption does not take place at the electron cyclotron resonance layer nor the upper hybrid resonance layer, but does happen midway between them. This is consistent with the ray tracing prediction, i.e., the poloidal field and poloidal inhomogeneity of toroidal field lead the B waves to have a large parallel refractive index N-parallel to (&gt;1), and the B waves are damped away via the Doppler-shifted cyclotron resonance.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN J APPLIED PHYSICS  

A field emitter array (FEA) is found to be useful for the production of pure electron plasmas. The FEA is robust and easy to handle under the ultra-high vacuum condition. The electrons from the FEA are accumulated in the trap and the accumulated electron number can be easily controlled by varying the potential depth or the trap.

Web of Science

researchmap

researchmap

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

researchmap

Language：Japanese   Publisher：日本航空宇宙学会  

researchmap

Language：Japanese   Publisher：日本航空宇宙学会  

researchmap

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Copyright © 2016 by the International Astronautical Federation (IAF). All rights reserved. The target of this study is to realize the continuous solid propellant producing technique for a cost reduction of solid rocket motor systems. In the process of the solid propellant manufacture, the mixing process controls the quality of the loaded solid propellant; the batch process is impossible to be replaced at present. We have considered the peristaltic pumping action mixer as one of the candidates for the continuous mixer. This mixer system is based on the artificial muscle actuator (soft actuator), and it is elongated and contracted by the pressurized gas. The system has some segments that has double rubber pipes (inner/outer), and the units can work independently. The outer rubber tube controls the shape change direction; the inner one works as a mixing chamber. The outer tube is swollen by the pressurized gas and the segments constrict axially; the inner tube inflates and the free volume can be changed. We expected that this mixer system has possible to replace the batch process by the continuous one. The peristaltic motion enables not only the mixing but also conveying even high viscosity slurry. The mixing mechanism by the soft actuator compress has no impact for the safety of the solid propellant handling. In this research, the mixing completeness of the composite solid propellant slurry by the peristaltic pumping mixer was estimated. The dispersion of the particle materials in the binder and the existing voids was observed by the X ray CT microscope. The solid propellant samples were made by our mixing system. The test materials were as follows: Hydroxyl terminated polybutadiene (HTPB) polymer as for the binder, aluminum powder as for the metallic fuel, dioctyladipate as for the plasticizer, ammonium perchlorate particles as for the oxidizer. The propellant composition was HTPB/AP/Al = 14/68/18 in massThe result showed that the mixer we proposed could mix the propellant slurry. The X ray CT scanning images showed that the solid materials well dispersed through the analysis of the luminance histograms.

Scopus

researchmap

Language：Japanese  

平成27年度宇宙輸送シンポジウム（2016年1月14日-15日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)）, 相模原市, 神奈川県資料番号: SA6000050036レポート番号: STCP-2015-037

researchmap

Language：Japanese  

平成27年度宇宙輸送シンポジウム（2016年1月14日-15日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)）, 相模原市, 神奈川県資料番号: SA6000050035レポート番号: STCP-2015-036

researchmap

Language：Japanese  

平成27年度宇宙輸送シンポジウム（2016年1月14日-15日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)）, 相模原市, 神奈川県著者人数: 11名資料番号: SA6000050033レポート番号: STCP-2015-034

researchmap

Language：Japanese  

J-GLOBAL

researchmap

researchmap

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

J-GLOBAL

researchmap

researchmap

researchmap

DOI： 10.1063/1.3491223

PubMed

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

DOI： 10.1109/ICIMW.2009.5324955

researchmap

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

researchmap

招待講演： プラズマ・核融合学会誌 編集委員会による推薦

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese   Publisher：プラズマ・核融合学会  

DOI： 10.1585/jspf.81.337

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese   Publisher：プラズマ・核融合学会  

CiNii Books

researchmap

Language：Japanese   Publisher：プラズマ・核融合学会  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese   Publisher：The Japan Society of Plasma Science and Nuclear Fusion Research  

An 89 GHz quasi-optical Electron Cyclotron Heating (ECH)/Current Drive (ECCD) system has been installed on the WT-3 tokamak. In order to investigate the effect of localized ECH/ECCD on the MHD instabilities, this system is designed to focus the micro-wave beam into a small focal spot with the radius about 1cm in the plasma center. This radius is smaller than the inversion radius of the sawtooth oscillation observed in WT-3. Utilizing this feature, the experiment on control of sawtooth oscillation by on-axis current drive have been performed. Stabilization of sawtooth by counter-ECCD is observed when the power deposition is localized inside the inversion radius. This result may be due to the decrease in current density near the magnetic axis. For the optimal coupling of the micro-wave to obliquely propagating waves at the plasma surface, a linear-elliptical polarization converter has been installed recently. This polarization converter may raise the effective current drive efficiency by a factor of 1.5 for the injected micro-wave power.

DOI： 10.1585/jspf.75.732

CiNii Books

researchmap

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10453640

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

researchmap

Venue：広島大学 東広島キャンパス  

researchmap

Venue：上智大学 四谷キャンパス  

researchmap

Venue：上智大学 四谷キャンパス  

researchmap

Venue：関西大学 100周年記念会館  

researchmap

Venue：宇宙科学研究所 相模原キャンパス (神奈川)  

researchmap

Venue：12 Lu Jiang Dao, Siming District, Xiamen 361001, China  

researchmap

Venue：12 Lu Jiang Dao, Siming District, Xiamen 361001, China  

researchmap

Venue：12 Lu Jiang Dao, Siming District, Xiamen 361001, China  

researchmap

Venue：12 Lu Jiang Dao, Siming District, Xiamen 361001, China  

researchmap

Venue：大阪工業大学 梅田キャンパス 2階セミナー室201･202 (大阪)  

researchmap

Venue：Ceratopia Toki, Toki-city, Gifu, Japan  

researchmap

Venue：Ceratopia Toki, Toki-city, Gifu, Japan  

researchmap

Venue：Ceratopia Toki, Toki-city, Gifu, Japan  

researchmap

Venue：AOSSA and Happiring, Fukui, Japan  

researchmap

Venue：東京電機大学 東京千住キャンパス ５号館 4Ｆ 5402教室  

researchmap

Venue：東京工業大学 (東京)  

researchmap

Venue：東京工業大学 (東京)  

researchmap

Venue：東京工業大学 (東京)  

researchmap

Venue：東京工業大学 (東京)  

researchmap

Venue：東京工業大学 (東京)  

researchmap

Venue：関西大学 100周年記念会館  

researchmap

Venue：久留米シティプラザ展示室 (福岡)  

researchmap

Venue：Toyama International Conference Center and ANA Crowne Plaza Toyama, Japan  

researchmap

Venue：Toyama International Conference Center and ANA Crowne Plaza Toyama, Japan  

researchmap

Venue：Toyama International Conference Center and ANA Crowne Plaza Toyama, Japan  

researchmap

Venue：東京電機大学 東京千住キャンパス（東京）  

researchmap

Venue：早稲田大学 西早稲田キャンパス/ベルサール高田馬場  

researchmap

Venue：早稲田大学 西早稲田キャンパス/ベルサール高田馬場  

researchmap

Venue：早稲田大学 西早稲田キャンパス/ベルサール高田馬場  

researchmap

Venue：早稲田大学 西早稲田キャンパス/ベルサール高田馬場  

researchmap

Venue：早稲田大学 西早稲田キャンパス/ベルサール高田馬場  

researchmap

Venue：早稲田大学 西早稲田キャンパス/ベルサール高田馬場  

researchmap

Venue：関西大学 100周年記念会館 第1会議室  

researchmap

Venue：朱鷺メッセ〔新潟コンベンションセンター〕3階ホワイエ (新潟)  

researchmap

Venue：Himegin Hole, Matsuyama, Ehime, Japan  

researchmap

Venue：Himegin Hole, Matsuyama, Ehime, Japan  

researchmap

Venue：パシフィコ横浜 2017(神奈川)  

researchmap

Venue：パシフィコ横浜 2017(神奈川)  

researchmap

Venue：関西大学 100周年記念会館 第3会議室  

researchmap

Venue：宇宙科学研究所 相模原キャンパス (神奈川)  

researchmap

Venue：宇宙科学研究所 相模原キャンパス (神奈川)  

researchmap

Venue：宇宙科学研究所 相模原キャンパス (神奈川)  

researchmap

Venue：Putah Creek Lodge, University of California, Davis, USA  

researchmap

Venue：Expo Guadarajara, Guadarajara, Mexico  

researchmap

Venue：函館アリーナ (北海道)  

researchmap

Venue：函館アリーナ (北海道)  

researchmap

Venue：東京工業大学 大岡山キャンパス  

researchmap

Venue：東京工業大学 大岡山キャンパス  

researchmap

Venue：東京工業大学 大岡山キャンパス  

researchmap

Venue：東京工業大学 大岡山キャンパス  

researchmap

Venue：関西大学 100周年記念会館 特別会議室  

researchmap

Venue：関西大学 100周年記念会館 特別会議室  

researchmap

Venue：宇宙科学研究所 相模原キャンパス (神奈川)  

researchmap

Venue：宇宙科学研究所 相模原キャンパス (神奈川)  

researchmap

Venue：宇宙科学研究所 相模原キャンパス (神奈川)  

researchmap

Venue：大分県別府市青山町5-73 豊泉荘 Ａ会場  

researchmap

Venue：関西大学 100周年記念会館 第3会議室  

researchmap

Venue：関西大学 100周年記念会館 第3会議室  

researchmap

Venue：大阪府吹田市 関西大学 100周年記念会館 第3会議室  

researchmap

Venue：大阪府大阪市 大阪産業大学 梅田サテライト  

researchmap

Venue：京都大学 桂キャンパス ローム記念館  

researchmap

Venue：京都市中京区 島津製作所 京都三条工場 SATIO 21号  

researchmap

Venue：大阪府吹田市 関西大学 100周年記念会館ホール  

researchmap

Venue：九州大学医学部 百年講堂 中ホール1  

researchmap

Venue：東京工業大学 大岡山キャンパス 本館H116  

researchmap

Venue：東京工業大学 大岡山キャンパス 本館H116  

researchmap

Venue：東京工業大学 大岡山キャンパス 本館H116  

researchmap

Venue：大阪府大阪市 大阪産大梅田サテライト  

researchmap

Venue：東京都豊島区 池袋大学  

researchmap

Venue：Albuquerque, New Mexico, United States  

researchmap

Venue：Orlando, Florida, United States  

researchmap

Venue：Toki, Gifu, Japan  

researchmap

Venue：Takayama, Gifu, Japan  

researchmap

Venue：Toki, Gifu, Japan  

researchmap

Venue：Williamsburg, Virginia, United States  

researchmap

Venue：Denver, Colorado, United States  

researchmap

Venue：Naka, Ibaraki, Japan  

researchmap

Venue：Montreux, Schweiz  

researchmap