A5018601063- Gyrotron and Vacuum Electronics Research
- Particle accelerators and beam dynamics
- Magnetic confinement fusion research
- Microwave Engineering and Waveguides
- Superconducting Materials and Applications
- Pulsed Power Technology Applications
- Stellar, planetary, and galactic studies
- Hydraulic and Pneumatic Systems
- Plasma Diagnostics and Applications
- Advanced Photonic Communication Systems
- Optical Network Technologies
- Rheology and Fluid Dynamics Studies
- Photonic and Optical Devices
- Statistical Mechanics and Entropy
- Advanced Memory and Neural Computing
- Astrophysics and Star Formation Studies
- Advanced Fiber Laser Technologies
- Combustion and Detonation Processes
- Fluid Dynamics and Vibration Analysis
- Plasma Applications and Diagnostics
- Fluid Dynamics and Turbulent Flows
- Astro and Planetary Science
- Flow Measurement and Analysis
- Quantum chaos and dynamical systems
- Water Systems and Optimization
National Institutes for Quantum Science and Technology
2021-2024
National Institute for Fusion Science
2021
Toshiba (Japan)
2002-2020
Hamamatsu University
2020
Osaka University
2006-2019
Hamamatsu Photonics (Japan)
2018-2019
Tohoku University
1982-2017
National Institute of Technology, Tsuruoka College
2017
Saitama University
2017
Japan Atomic Energy Agency
2007-2016
The design progress in a compact low aspect ratio (low A ) DEMO reactor, ‘SlimCS’, and its issues are reported. study focused mainly on the torus configuration including blanket, divertor, materials maintenance scheme. For continuity with Japanese ITER-TBM, blanket is based water-cooled solid breeder blanket. vertical stability of elongated plasma high beta access, segmented into replaceable permanent blankets sector-wide conducting shell arranged inbetween these blankets. numerical...
A 24 MW Electron Cyclotron (EC) system operating at 170 GHz and 3600 s pulse length is to be installed on ITER. The EC plant shall deliver 20 of this power the plasma for Heating Current Drive (H&CD) applications. designed initiation, central heating, current drive, profile tailoring, Magneto-hydrodynamic control (in particular, sawteeth Neo-classical Tearing Mode) in flat-top phase plasma. preliminary design review was performed 2012, which identified a need extended application...
Laser plasma interactions in a relativistic parameter regime have been intensively investigated for studying the possibility of fast ignition inertial confinement fusion (ICF). Using ultra-intense laser systems and particle-in-cell (PIC) simulation codes, light self-focusing, super hot electrons, ions, neutron production, are studied. The experiments performed with 50 J energy, 0.5–1 ps pulse at 1053 nm wavelength intensity 1019 W/cm2. Most shots studied under preformed conditions 100 μm...
Propagation of an ionization front in the beam channel was observed after plasma generated using a 170GHz millimeter-wave atmosphere. The propagation velocity found to be supersonic when power density greater than 75kWcm−2. momentum coupling coefficient Cm, ratio propulsive impulse input energy, measured conical and cylindrical thruster models. A Cm value 350NMW−1 recorded propagated with velocity.
A 170 GHz gyrotron has been developed at JAEA, which achieved operation of 1 MW/800 s and up to 55% efficiency. This is the first demonstration a achieving even exceeding ITER operating requirements MW/500 50% In addition demonstrated for h with an output power 0.6 MW. The oscillation was stable all cooling water temperatures vacuum pressure reaching equilibrium conditions during pulse length either level. successful aided by very low level stray radiation (∼2% power), contributed fast...
Recent progress on the high power gyrotron development in JAEA is presented. The featured to have a triode-type magnetron injection gun, cylindrical resonator working at 170 GHz with TE 31,8 mode, water-cooled diamond window and depressed collector. After demonstration of ITER basic performance, has been operated for 3 years, recorded ∼200 GJ total output energy. Next, which oscillates higher order 31,12 , designed fabricated study long pulse oscillation greater than 1 MW. In parallel,...
A large sized synthetic diamond window assembly was installed on a 170 GHz gyrotron. An aperture and thickness of the are 83 2.23 mm, respectively, whose edge directly cooled by water. Gyrotron performances 520 kW at 6.2 s 450 8 were attained. temperature increase stabilized after ∼5 s, whereas power had been limited to below with conventional windows. This drastic improvement deliverable obtained from outstanding properties diamond, that is, an extremely high thermal conductivity (∼1800...
Development of 170 and 110 GHz gyrotrons their application to electron cyclotron heating systems are presented. A parasitic oscillation that degraded the beam quality was suppressed, performance gyrotron improved significantly. Up now, 0.9 MW/9.2 s, 0.5 MW/30 0.3 MW/60 0.2 MW/132 etc, have been demonstrated at GHz. At GHz, 1.3 MW/1.5 1.2 MW/4.1 1 MW/5 s were obtained. It is found reduction stray radiation enhancement cooling capability important for continuous wave operation. Four under...
Long-scale jetlike x-ray emission was observed in a 100-TW laser-plasma interaction. The jet well collimated with divergence of 30-40 mrad and continued from the target surface into underdense regions for distance over 4 mm specular direction laser light. A two-dimensional particle-in-cell simulation shows an electron acceleration specularly reflected light collimation stream by self-generated magnetic field, resulting to
We demonstrate a resolution upgrade toward 6 bit optical quantization using power-to-wavelength conversion without an increment of system parallelism. Expansion full-scale input range is employed in conjunction with reduction step size keeping sampling-rate transparency characteristic over several 100 sGS/s. The effective number bits estimated to 5.74 bit, and the integral nonlinearity error differential are less than 1 least significant bit.
To satisfy the electrical and thermomechanical requirements for a continuous wave millimeter beam transmission, window assembly using large size synthesized diamond disk has been developed. Such systems are needed as vacuum barrier tritium shielding in future electron cyclotron heating fusion plasma noninductive current drive. The used this study was manufactured by chemical vapor deposition (CVD) consists of polycrystalline 96 mm diameter 2.23 thick. built into an which two Inconel tubes...
We demonstrated spectral compression of ultrashort soliton pulses in a wide wavelength region based on an adiabatic technique using comb-profile fiber. The fiber was carefully designed numerical analysis and fabricated conventional single-mode dispersion-shifted width 200 fs pulse compressed from 12 to 15 nm 0.54-0.71 the 1620-1850 nm, giving factor up 19.8-25.9. Owing effect, side lobe level suppressed -19.2 -9.7 dB.
We report the attempt of optical quantization and coding in 5-bit parallel format for photonic A/D conversion. The proposed system is designed to realize generation 32 different codes proportion corresponding signal levels when fed a certain range amplitude-varied input pulses setup. Optical bit-parallel made it possible, that provides 5 bit from quantized pulses. operation an module with multi-ports was tested our experimental
The transmission line (TL) subsystem associated with the ITER electron cyclotron heating and current drive system has reached conceptual design maturity. At this stage responsibility of finalizing been transferred from Organization to U.S. Domestic Agency. purpose TL is transmit microwaves generated by 170-GHz gyrotrons installed in radio-frequency building launchers located one equatorial four upper tokamak ports. Each consists evacuated HE11 waveguides, direct-current breaks, power...
Covers advancements in spacecraft and tactical strategic missile systems, including subsystem design application, mission analysis, materials structures, developments space sciences, processing manufacturing, operations, applications of technologies to other fields.
An experiment was conducted on a microwave rocket (repetitive-pulse millimeter-wave-beam-powered thruster) with repetitive pulses. A thruster model forced-breathing system used. The supplies fresh air from the thrust wall into thruster. pressure histories in weremeasured and propagation velocity of shock wave impulse were deduced. Results show that although identical to result for single-pulse operation at first pulse, increased after second pulse. Similarly, decreased dependence performance...
A high power dual-frequency gyrotron is designed and tested. The design based on a 170 GHz single-frequency with triode magnetron injection gun (MIG). MIG enables to choose variety of oscillation modes for different frequencies suitable pitch factor, which the great advantage multi-frequency gyrotron. Another frequency 137 selected in order use 1.853-mm-thick single-disk output window. Cavity are TE31,11 TE25,9 GHz, respectively, have mode conversion efficiency RF beam similar radiation...
We report the experimental demonstration of a 10-GS/s 5-bit real-time optical quantization using soliton self-frequency shift (SSFS) and multistage spectral compression. prove feature sampling rate transparency at 10 GS/s by transmitting 10-Gb/s multi-intensity level quasi analog signals through our quantizer. Furthermore, to confirm performance quantizer, we measure bit-error-rate calculate effective number bits, integral nonlinearity error, differential error.
Quasi-steady-state high βp H mode discharges performed by suppressing neoclassical tearing modes (NTMs) are described. Two operational scenarios have been developed for long sustainment of the discharge: NTM suppression profile optimization, and stabilization local electron cyclotron current drive (ECCD)/electron heating (ECH) at magnetic island. Through optimization pressure safety factor profiles, a plasma with H89PL = 2.8, HHy,2 1.4, ≈ 2.0 βN 2.5 has sustained 1.3 s small values...
A scanning tunneling microscope dedicated to in situ experiments under the irradiation of highly brilliant hard-X-rays synchrotron radiation has been developed. In microscopy (STM) observation was enabled by developing an accurate alignment system ultrahigh vacuum. Despite noisy conditions facility and load around probe tip, STM images were successfully obtained at atomic resolution. Tip-current spectra for Ge nano-islands on a clean Si(111) surface changing incident photon energy across...