A5037553494- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Venous Thromboembolism Diagnosis and Management
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Magnetic Field Sensors Techniques
- Magnetic Properties and Applications
- Astrophysics and Cosmic Phenomena
- Atrial Fibrillation Management and Outcomes
- Electric Motor Design and Analysis
- Cardiac Valve Diseases and Treatments
- Particle accelerators and beam dynamics
- Infective Endocarditis Diagnosis and Management
- Gamma-ray bursts and supernovae
- Dust and Plasma Wave Phenomena
- Laser-induced spectroscopy and plasma
- Geomagnetism and Paleomagnetism Studies
- Cardiac Imaging and Diagnostics
- Acute Ischemic Stroke Management
- Gas Dynamics and Kinetic Theory
- Cardiovascular Function and Risk Factors
- Cardiac tumors and thrombi
- DNA and Nucleic Acid Chemistry
- Antiplatelet Therapy and Cardiovascular Diseases
National Institute for Fusion Science
2012-2024
Kansai Electric Power Hospital
2022-2024
National Institutes of Natural Sciences
2008-2024
The University of Tokyo
2019-2024
Kansai Electric Power (Japan)
2023
Kyoto University
2023
The Graduate University for Advanced Studies, SOKENDAI
2017
Nagoya University
2001-2004
Waves propagating perpendicular to a magnetic field in plasma consisting of electrons, positrons, and ions are studied theoretically numerically. In three component plasma, there appears frequency domain which the magnetosonic waves cannot propagate; thus, we have two separate modes below electron cyclotron frequency. Their dispersion relations discussed. Then, Korteweg–de Vries equations derived for these modes. A solitary wave low-frequency mode has soliton width 1–103 times as large skin...
Abstract In tokamak plasma merging experiments, high-power ion heating is achieved only when the current sheet thickness compressed to gyroradius. The magnetic reconnection converts 40-50% of reconnecting field energy into with scaling law proportional square field. If larger than gyrodadius, 5-10% energy. can be understood from experimental finding that poloidal electric due electrostatic quadrupolar potential in downstream region increases linearly both and guide
Background Real-world data on clinical characteristics and outcomes related to the use of different direct oral anticoagulants (DOACs) for cancer-associated venous thromboembolism (VTE) is lacking. Methods The COMMAND VTE Registry-2 a multicenter registry enrolling 5,197 consecutive patients with acute symptomatic from 31 centers in Japan January 2015 August 2020. Our study population comprised 1,197 active cancer who were divided into edoxaban (N = 643, 54%), rivaroxaban 297, 25%), apixaban...
Background: Data on concomitant mitral regurgitation (MR) in patients with severe aortic stenosis (AS) are scarce.
Abstract There were no data comparing the in-hospital outcomes after transcatheter aortic valve implantation (TAVI) with those surgical replacement (SAVR) in Japan. Among consecutive patients severe AS between April 2018 and December 2020 CURRENT Registry-2, we identified 1714 who underwent (TAVI group: 1134 patients, SAVR 580 patients). Patients TAVI group much older (84.4 versus 73.6 years, P < 0.001) more often had comorbidities than group. In-hospital death rate was numerically lower...
The mechanism of plasma heating through magnetic reconnection with a guide field is investigated by means two-dimensional electromagnetic particle simulations. These simulations mimic the dynamics two torus plasmas merging in spherical tokamak (ST) device. It found that large part protons, which behave as nonadiabatic, are effectively heated downstream because ring-like structure proton velocity distribution observed at local point downstream. characteristic features can be explained...
The dependence of the ion effective heating on poloidal (reconnection) and toroidal (guide) magnetic fields during reconnection in presence a guide field is investigated by means particle simulations, which mimic merging plasmas spherical tokamak. In previous works, our simulations demonstrated that temperature perpendicular to grows mainly downstream, ring-shaped velocity distributions are formed. This ions effectively heated. basic theory explains distribution formed rotate around while E...
A multi-hierarchy simulation model aimed at magnetic reconnection studies has been developed, in which macroscopic and microscopic physics are solved self-consistently simultaneously. In this work, the previous by these authors is extended to a more realistic one with non-uniform space grids. Based on domain decomposition method, consists of three parts: magnetohydrodynamics algorithm express global dynamics, particle-in-cell describe kinetic physics, an interface interlock macro micro...
The influence of a guide field on collisionless driven reconnection is investigated by means two-dimensional electromagnetic particle simulation in an open system. In quasi-steady state when electric evolves fully, current layer locally narrow kinetic region and its scale decreases proportion to electron meandering as the intensified. Here, stands for average spatial nongyrotropic motions vicinity point. Force terms associated with off-diagonal components ion pressure tensors, which are...
Positron acceleration in oblique shock waves is studied with relativistic, electromagnetic, particle simulations full dynamics. In the simulations, some positrons have been accelerated to energies γ∼600, where γ Lorentz factor. The electric field parallel magnetic plays an essential role acceleration; it prevents from passing through wave. For certain propagation velocities and angles, these stay around front for long periods of time, moving roughly external field, gain great energies. These...
Incessant acceleration of nonthermal fast ions by an oblique magnetosonic shock wave is studied with hybrid simulations. First, magnetic and electric field profiles are obtained means a one-dimensional, relativistic, electromagnetic, particle simulation. Test trajectories then calculated using these profiles. Some trapped the owing to relativistic effect that velocity limited speed light while momentum can grow indefinitely. In simulations, some found suffer energy jumps several tens times;...
There is scarce data evaluating the current practice pattern and clinical outcomes for patients with severe aortic stenosis (AS), including both those who underwent surgical valve replacement (SAVR) or transcatheter implantation (TAVI) were managed conservatively in TAVI era.
A multi-hierarchy simulation model for magnetic reconnection studies is developed in which macroscopic and microscopic physics are expressed consistently simultaneously. We the first to have successfully demonstrated collisionless driven framework of a model. Magnetic found occur micro-hierarchy upon plasma injection from macro-hierarchy.
Multi-hierarchy physics in magnetic reconnection is investigated using two kinds of numerical simulation models: the electromagnetic particle model for an open system (PASMO) and magnetohydrodynamic particle-in-cell (MHD-PIC) interlocked multi-hierarchy reconnection. A series studies PASMO code have disclosed that ion electron dissipation regions form inside a kinetic regime which meandering orbit effects are crucial triggering collisionless (CR). Anomalous resistivity leading to CR also...
Motions of nonthermal, fast ions in an oblique shock wave are studied theoretically and numerically. After the encounter with a wave, some get to move it. Their energies then increase once each gyroperiod. momenta parallel magnetic field also increase. Thus, these particles eventually escape, going away ahead wave. However, it is predicted that under certain circumstances, owing relativistic effects, cannot go faster direction propagation than Some therefore escape from Accordingly,...
Electron dynamics and energization are one of the key components magnetic field dissipation in collisionless reconnection. In 2D numerical simulations reconnection, main mechanism that limits current density provides an effective is most probably electron pressure tensor term, which has been shown to break frozen-in condition at x-point. addition, electron-meandering-orbit scale controls width region, where temperature observed increase both recent Magnetospheric Multiple-Scale (MMS)...
The motion of ultrarelativistic particles in an oblique plasma wave is theoretically studied. Making use the relation vdγ/dt≫γdv/dt, where γ Lorentz factor, zeroth-order velocity and energy increase rate are obtained. This solution applicable to any particle species. nearly parallel external magnetic field when vsh∼c cos θ, vsh propagation speed θ angle between normal field. perturbed motions ions positrons then separately discussed. Their perturbations both perpendicular velocity. ion...
In order to perform a computer simulation of large time and spatial scale system, such as fusion plasma device solar-terrestrial plasma, macro model, where micro physics is modeled analytically or empirically, usually used. However, kinetic effects wave-particle interaction play important roles in most nonlinear phenomena result anomalous behavior. This limits the applicability models. past few years several attempts have been performed overcome this difficulty. Two types multi-scale method...
Two different types of merging processes spheromak-like plasmoids (SPs) without any external guide-field (toroidal) component, which are confined in a rectangular conducting vessel, have been investigated by means two-dimensional PIC simulation, i.e., counter-helicity and co-helicity processes. The time scale is given the transit for ion sound wave to travel from center SP initial profile reconnection point both cases. Through process, toroidal magnetic field energy effectively converted...