A5033676070- Magnetic confinement fusion research
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Physics of Superconductivity and Magnetism
- Solar and Space Plasma Dynamics
- Gyrotron and Vacuum Electronics Research
- Structural Load-Bearing Analysis
- Dust and Plasma Wave Phenomena
- Structural Behavior of Reinforced Concrete
- Laser-induced spectroscopy and plasma
- Nuclear reactor physics and engineering
- Particle Accelerators and Free-Electron Lasers
- Spacecraft and Cryogenic Technologies
- Nuclear Materials and Properties
- Atomic and Subatomic Physics Research
- HVDC Systems and Fault Protection
- Nuclear Physics and Applications
- Frequency Control in Power Systems
- Seismic Performance and Analysis
- Atomic and Molecular Physics
- Magnetic and transport properties of perovskites and related materials
Princeton Plasma Physics Laboratory
2015-2024
Princeton University
2009-2024
Osaka University
2019-2022
Kyushu University
2019-2021
The University of Tokyo
2003-2021
National Institutes for Quantum Science and Technology
2021
University of Wisconsin–Madison
2021
Edgewood College
2021
Japan Science Society
2016-2019
The Japanese Society of Gastroenterological Surgery
2016
A sharp transport barrier, accompanied by a bifurcated poloidal rotation and radial electric field, is formed at the plasma edge driving current across outer magnetic surfaces of tokamak. decrease in particle observed for negative E fields. When turned off, field damp on time scale comparable with ion-ion collision time.
Abstract The objectives of NSTX-U research are to reinforce the advantages STs while addressing challenges. To extend confinement physics low- A , high beta plasmas lower collisionality levels, understanding transport mechanisms that set performance and pedestal profiles is being advanced through gyrokinetic simulations, reduced model development, comparison NSTX experiment, as well improved simulation RF heating. develop stable non-inductive scenarios needed for steady-state operation,...
The National Spherical Torus Experiment (NSTX) is being built at Princeton Plasma Physics Laboratory to test the fusion physics principles for spherical torus concept MA level. NSTX nominal plasma parameters are R0 = 85 cm, a 67 R/a ⩾ 1.26, Bt 3 kG, Ip 1 MA, q95 14, elongation κ ⩽ 2.2, triangularity δ 0.5 and pulse length of up 5 s. heating/current drive tools high harmonic fast wave (6 MW, s), neutral beam injection (5 80 keV, s) coaxial helicity injection. Theoretical calculations predict...
Abstract The spherical tokamak (ST) is a leading candidate for Fusion Nuclear Science Facility (FNSF) due to its compact size and modular configuration. National Spherical Torus eXperiment (NSTX) MA-class ST facility in the US actively developing physics basis an ST-based FNSF. In plasma transport research, experiments exhibit strong (nearly inverse) scaling of normalized confinement with collisionality, if this trend holds at low high fusion neutron fluences could be achievable very...
National Spherical Torus Experiment [which M. Ono et al., Nucl. Fusion 40, 557 (2000)] high-power divertor plasma experiments have shown, for the first time, that benefits from lithium coatings applied to facing components found previously in limited plasmas can occur also diverted configurations. Lithium were with pellets injected into helium discharges, and an oven directed a collimated stream of vapor toward graphite tiles lower center stack divertor. depositions few milligrams 1g been...
Abstract A fusion nuclear science facility (FNSF) could play an important role in the development of energy by providing environment needed to develop materials and components. The spherical torus/tokamak (ST) is a leading candidate for FNSF due its potentially high neutron wall loading modular configuration. key consideration choice configuration range achievable missions as function device size. Possible include: fluence, demonstrating tritium self-sufficiency, electrical self-sufficiency....
Research in NSTX has been conducted to establish spherical torus plasmas be used for high β, auxiliary heated experiments. This device a major radius R0 = 0.86 m and midplane halfwidth of 0.7 m. It operated with toroidal magnetic field B0 ⩽ 0.3 T Ip 1.0 MA. The evolution the plasma equilibrium is analysed between discharges an automated version EFIT code. Limiter, double null lower single diverted configurations have sustained several energy confinement times. stored reached 92 kJ (βt 17.8%)...
We have developed a Maglev train under the guidance of Japanese Ministry Transport. The is an advanced that can run more than 500 km/h with linear synchronous motor (LSM) has both superconducting magnet on board and armature coil in ground. was tested Yamanashi test line. Tests began 1997, which exercised various functions performance. main results tests are reported this article.
Liquid metal plasma-facing components (PFCs) have been proposed as a means of solving several problems facing the creation economically viable fusion power reactors. To date, few demonstrations exist this approach in diverted tokamak and we here provide an overview such work on National Spherical Torus Experiment (NSTX). The Lithium Divertor (LLD) was installed operated for 2010 run campaign using evaporated coatings filling method. LLD consisted copper-backed structure with porous...
Abstract ST40 is a compact, high-field ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>B</mml:mi> <mml:mi mathvariant="normal">T</mml:mi> <mml:mn>0</mml:mn> </mml:mrow> </mml:msub> <mml:mtext>⩽</mml:mtext> <mml:mn>2.1</mml:mn> <mml:mstyle scriptlevel="0"/> <mml:mtext>T</mml:mtext> </mml:math> ) spherical tokamak (ST) with mission to expand the physics and technology basis for ST route commercial fusion. The research programme covers...
Ion Bernstein wave heating (IBWH) utilizes the ion (IBW), a hot plasma wave, to carry radio frequency (rf) power heat tokamak reactor core. Earlier accessibility studies have shown that this finite-Larmor-radius (FLR) mode should penetrate into dense core without significant attenuation. Moreover, IBW’s low perpendicular phase velocity (ω/k⊥≊VTi≪Vα) greatly reduces otherwise serious absorption by 3.5 MeV fusion α particles. In addition, property of k⊥ρi≊1 makes localized bulk possible at...
High harmonic fast magnetosonic waves in high beta plasmas are investigated. In the regime, a combination of reduced group velocity and enhancement magnetic pumping lead to such large values electron absorption that one can expect strong (≊100%) single pass absorption. particular, by controlling wave spectrum, prospect localized heating current drive appears be feasible low-aspect-ratio tokamak regimes. Inclusion finite-Larmor-radius terms reveals an accessibility limit ion regime (βi≊50%...
A tokamak discharge has been formed and maintained through helicity injection, by use of only an external dc low-energy electron beam. The discharge, in a 5-kG toroidal field, evolved to steady-state circular cross section with q(a)=10, q(0)=4, which was for more than 400 L/R periods, the time (60 msec) limited cathode bias supply. density profile reached line-averaged n${\ifmmode\bar\else\textasciimacron\fi{}}_{e}$=2\ifmmode\times\else\texttimes\fi{}${10}^{13}$...
The National Spherical Torus Experiment (NSTX) has undergone a major upgrade, and the NSTX Upgrade (NSTX-U) Project was completed in summer of 2015.NSTX-U first plasma subsequently achieved, diagnostic control systems have been commissioned, H-mode accessed, magnetic error fields identified mitigated, physics research campaign carried out.During ten run weeks operation, NSTX-U surpassed record pulse-durations toroidal (TF), high-performance ~1 MA plasmas comparable to best sustained near...
AbstractThe mission of the National Spherical Torus Experiment (NSTX) is to prove principles spherical torus physics by producing high-βt plasmas that are noninductively sustained and whose current profiles in steady state. The NSTX will be one first ultralow-aspect-ratio tori (R/a ≤ 1.3) operate at high power (Pinput up 11 MW) produce (25 40%), low-collisionality, high-bootstrap-fraction (≤70%) discharges. Both radio-frequency neutral beam heating drive employed. Built into sufficient...
Global magnetohydrodynamic (MHD) stability limits in the National Spherical Torus Experiment (NSTX) have increased significantly recently due to a combination of device and operational improvements. First, more routine H-mode operation with broadened pressure profiles allows access higher normalized β lower internal inductance. Second, correction poloidal field coil induced error-field has largely eliminated locked tearing modes during normal maximum achievable β. As result these...
A noninductive current drive concept, based on internal pressure-driven currents in a low-aspect-ratio toroidal geometry, has been demonstrated the Current Drive Experiment Upgrade (CDX-U) [Forest et al., Phys. Rev. Lett. 68, 3559 (1992)] and further tested DIII-D [in Plasma Physics Controlled Nuclear Fusion Research, 1986, Proceedings of 11th International Conference, Kyoto (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 159]. For both experiments, electron cyclotron power...
Pressure driven currents are observed in an electron cyclotron resonance (ECR) heated, small-aspect-ratio toroidal plasma the CDX-U device. A current of 1.05 kA was generated with \ensuremath{\sim}8 kW ECR power. At this level, poloidal field created by these is significantly larger than vacuum and produces closed flux surfaces a tokamak geometry. After surface formation we hypothesize that bootstrap to maintain discharge. This internally may offer attractive method start up
The spherical torus or tokamak (ST) is a member of the family with its aspect ratio (A = R0/a) reduced to A ∼ 1.5, well below normal operating range ≥ 2.5. As reduced, ideal beta β (radio plasma magnetic pressure) stability limit increases rapidly, approximately as 1/A. current it can sustain for given edge safety factor q-95 also rapidly. Because above, natural elongation κ, which makes shape appear spherical, ST configuration yield exceptionally high performance in compact geometry. Due...
Coaxial Helicity Injection (CHI) on the National Spherical Torus Experiment (NSTX) has produced 240kA of toroidal current without use central solenoid.Values multiplication ratio (CHI / injector current) up to 10 were obtained, in agreement with predictions.The discharges which lasted for 200ms, limited only by programmed waveform are more than an order magnitude longer duration that any CHI previously a Spheromak or (ST).
Research on the stability of spherical torus plasmas at and above no-wall beta limit is being addressed National Spherical Torus Experiment [M. Ono et al., Nucl. Fusion 40, 557 (2000)], that has produced low aspect ratio plasmas, R/a∼1.27 plasma current exceeding 1.4 MA with high energy confinement (TauE/TauE_ITER89P&gt;2). Toroidal normalized have exceeded 25% 4.3, respectively, in q∼7 plasmas. The observed to increase then saturate increasing li. factor βN/li reached 6, limited by...
The highly indented plasmas of the PBX-M tokamak experiment [Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Vienna, 1989), Vol. 1, p. 97] have reached plasma regimes both high volume-averaged beta (βt), high-beta poloidal (βp), show evidence suppression external surface modes by passive stabilizing system. Values βt up to 4.0 I/aB (% MA/m T) with Ti(0)≊4 keV been obtained. A magnetohydrodynamic analysis βp=2.0 indicates that these are near threshold second stability regime....
The major objective of the National Spherical Torus Experiment (NSTX) is to understand basic toroidal confinement physics at low aspect ratio and high βT in order advance spherical torus (ST) concept. In do this, NSTX utilizes up 7.5 MW neutral beam injection, 6 harmonic fast waves (HHFWs), it operates with plasma currents 1.5 MA elongations 2.6 a field 0.45 T. New facility, diagnostic modelling capabilities developed over past two years have enabled research team make significant progress...