A5040947454- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Fusion materials and technologies
- Laser-Plasma Interactions and Diagnostics
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Laser-induced spectroscopy and plasma
- Plasma Diagnostics and Applications
- Nuclear Physics and Applications
- High-pressure geophysics and materials
- Laser-Matter Interactions and Applications
- Dust and Plasma Wave Phenomena
- Markov Chains and Monte Carlo Methods
- Semiconductor materials and devices
- Atomic and Molecular Physics
- Ion-surface interactions and analysis
- Theoretical and Computational Physics
- Anomaly Detection Techniques and Applications
- Nuclear Materials and Properties
- Advanced Data Storage Technologies
- Geotechnical and Geomechanical Engineering
- Radiation Detection and Scintillator Technologies
- GaN-based semiconductor devices and materials
National Institutes for Quantum Science and Technology
2016-2024
National Institute for Fusion Science
2016-2024
Princeton Plasma Physics Laboratory
2021-2022
Princeton University
2021-2022
Fusion Academy
2019
Fusion (United States)
2019
Japan Atomic Energy Agency
2011-2015
Max Planck Institute for Plasma Physics
2007-2015
Max Planck Society
2015
University of California, Irvine
2009
Abstract The JET 2019–2020 scientific and technological programme exploited the results of years concerted engineering work, including ITER-like wall (ILW: Be W divertor) installed in 2010, improved diagnostic capabilities now fully available, a major neutral beam injection upgrade providing record power 2019–2020, tested technical procedural preparation for safe operation with tritium. Research along three complementary axes yielded wealth new results. Firstly, plasma delivered scenarios...
Dedicated experiments to generate energetic D ions and fusion-born alpha particles were performed at the Joint European Torus (JET) with ITER-like wall (ILW). Using 3-ion radio frequency (RF) heating scenario, deuterium from neutral beam injection (NBI) accelerated in core of mixed plasmas higher energies ion cyclotron resonance (ICRF) waves, turn leading a core-localized source particles. The fast-ion distribution RF-accelerated D-NBI was controlled by varying ICRF NBI power ( 4–6 MW, 3–20...
A multi-phase simulation that is a combination of classical and hybrid for energetic particles interacting with magnetohydrodynamic (MHD) fluid developed to simulate the nonlinear dynamics on slowing down time scale particles. The code extended realistic beam deposition profile, collisions losses, used both phases. run without MHD perturbations in phase, while interaction between simulated phase. In DIII-D discharge #142111, stored ion energy saturated due Alfvén eigenmodes (AE modes) at...
A multi-phase simulation, which is a combination of classical simulation and hybrid for energetic particles interacting with magnetohydrodynamic (MHD) fluid including neutral beam injection, slowing-down, pitch angle scattering, applied to DIII-D discharge #142111 where the fast ion spatial profile significantly flattened due multiple Alfvén eigenmodes (AEs).The large pressure flattening observed experimentally successfully reproduced by these first kind comprehensive simulations.Temperature...
Abstract In the late 1990s, fusion scientists at Japanese tokamak JT-60U discovered abrupt large-amplitude events during beam-driven deuterium plasma experiments. A large spike in magnetic fluctuation signal followed by a drop neutron emission rate indicates that energetic ions abruptly migrate out of core an intense burst Alfvén waves lasts only 0.3 ms. With continued beam injection, ion population recovers until next event occurs 40–60 ms later. Here we present results from simulations...
Abstract The instability that was previously identified (Gorelenkov 2009 Phys. Plasmas 16 056107) as a fast-ion driven beta-induced Alfvén-acoustic eigenmode (BAAE) in DIII-D misidentified. In dedicated experiment, low frequency modes (LFMs) with characteristic ‘Christmas light’ patterns of brief linked to the safety factor evolution occur plasmas electron temperature T e ≳ 2.1 keV but modest beta. To isolate importance different driving gradients on these modes, cyclotron heating (ECH)...
Long-pulse operation of a self-sustained fusion reactor using toroidal magnetic containment requires control over the content alpha particles produced by D-T reactions. On one hand, MeV-class must stay confined to heat plasma. other decelerated helium ash be expelled before diluting fuel. Here, we report results kinetic-magnetohydrodynamic hybrid simulations large tokamak plasma that confirm existence parameter window where such energy-selective confinement can accomplished exploiting...
In magnetic configurations with two or three q=1 (with q being the safety factor) resonant surfaces in a tokamak plasma, resistive magnetohydrodynamic modes poloidal mode numbers m much larger than 1 are found to be linearly unstable. It is that these high-m double triple tearing significantly enhance through nonlinear interactions growth of m=1 mode. This may account for sudden onset internal kink, i.e., fast sawtooth trigger. Based on subsequent reconnection dynamics can proceed without...
Configurations with nearby multiple resonant surfaces have broad spectra of linearly unstable coupled tearing modes dominant high poloidal mode numbers m. This was recently shown for the case q=1 resonances [Bierwage et al., Phys. Rev. Lett. 94 65001 (2005)]. In present work, similar behavior is found double (DTM) on q⩾1. A detailed analysis linear instability characteristics DTMs various m performed using numerical simulations. The structures and dispersion relations are calculated....
Magnetohydrodynamic (MHD) instabilities driven by energetic alpha particles and beam deuterium are investigated for ITER operation scenarios using a hybrid simulation code interacting with an MHD fluid. The particle method finite Larmor radius effects is applied to both particles. For the steady-state scenario 9 MA plasma current, beta-induced Alfvén eigenmodes (BAE modes) low toroidal mode number (n = 3, 5) were found become dominant in nonlinear phase although many (TAE n ∼ 15 most...
Recurring bursts of chirping Alfvén modes that were observed in JT-60U tokamak plasmas driven by negative-ion-based neutral beams (N-NB) are reproduced first-principle simulations performed with an extended version the hybrid code MEGA. This simulates interactions between gyrokinetic fast ions and magnetohydrodynamic (MHD) presence a realistic ion source collisions, so it self-consistently captures dynamics across wide range time scales (0.01–100 ms). The simulation confirms experimentally...
The exponential growth phase of fast-ion-driven Alfvénic instabilities is simulated and the resonant wave-particle interactions are analyzed numerically. simulations carried out in realistic magnetic geometry with a particle distribution for JT-60U plasma driven by negative-ion-based neutral beams. In order to deal large drifts fast ions, two new mapping methods developed applied. first yields radii pitch angles at points, where unperturbed orbit intersects mid-plane. These canonical...
Abstract The parameter <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>R</mml:mi> <mml:mi mathvariant="normal">D</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mi>P</mml:mi> <mml:mi>rad</mml:mi> <mml:mo>/</mml:mo> <mml:mi>cond</mml:mi> </mml:math> , which measures the ratio of radiated power to conductive heat flux at downstream Scrape-Off-Layer (SOL), is proposed as a robust and practically useful figure merit for divertor...
The effect of a narrow sub-Alfvénic shear flow layer near the minimum qmin tokamak safety factor profile in configuration with reversed central is analyzed. Sufficiently strong velocity gives rise to broad spectrum fast growing Kelvin-Helmholtz (KH)-like ideal magnetohydrodynamic modes dominant mode numbers m,n∼10. Nonlinear simulations finite resistivity show magnetic reconnection ripples caused by KH-like vortices, formation turbulent structures, and flattening profile. KH are compared...
The mutual nonlinear interactions of shear Alfvén modes and alpha particles can enhance their transport in burning plasmas. Theoretical numerical works have shown that rapid energetic ions take place because fast growing (e.g. particle driven modes, EPMs). This kind has been observed experiments as well simulations. Hybrid MHD-gyrokinetic codes investigate linear dynamics (EP) retaining the interaction between waves EPs self-consistently. Self-consistent wave–particle (both configuration...
The JT-60SA tokamak, being built under the Broader Approach agreement jointly by Europe and Japan, is due to start operation in 2020 expected give substantial contributions both ITER DEMO scenario optimisation. A broad set of preparation activities for an efficient experiments on carried out, involving elaboration Research Plan, advanced modelling various domains, feasibility conception studies diagnostics other sub-systems connection with priorities scientific programme, development...
JT-60SA, the largest tokamak that will operate before ITER, has been designed and built jointly by Japan Europe, is due to start operation in 2020.Its main missions are support ITER exploitation contribute demonstration fusion reactor machine scenario design.Peculiar properties of JT-60SA its capability produce long-pulse, high-β, highly shaped plasmas.The preparation Research Plan, plasma scenarios, producing physics results not only relevant future experiments, but often constitute...
Abstract The fast ion dynamics and the associated heat load on plasma facing components in KSTAR tokamak were investigated with orbit following Monte-Carlo (OFMC) code several magnetic field configurations realistic wall geometry. In particular, attention was paid to effect of resonant perturbation (RMP) fields. Both vacuum approximation as well self-consistent that includes response a stationary considered. both cases, (MP) is dominated by toroidal mode number n = 1, but otherwise its...
Abstract The mission of the low aspect ratio spherical tokamak NSTX-U is to advance physics basis and technical solutions required for optimizing configuration next-step steady-state fusion devices. will ultimately operate at up 2 MA plasma current 1 T toroidal field on axis 5 s, has available 15 MW neutral beam injection power different tangency radii 6 high harmonic fast wave heating. With these capabilities develop understanding control tools ramp-up sustain performance fully...
The hybrid code MEGA is used to simulate an abrupt large-amplitude event (ALE) in JT-60U shot E039672 that was strongly driven by a pair of negative-ion-based neutral beams (N-NBs). This configuration known be unstable energetic particle modes (EPMs) with toroidal mode number n = 1. purpose this study look for threshold respect the on-axis fast ion beta value, βh0, beyond which EPM undergoes convective amplification (CA) and causes significant transport. motivated hypothesis such may work as...
Dynamics of fast ions and shear Alfvén waves are simulated using MEGA, a global nonlinear hybrid code. The scenario considered is based on JT-60U shot E039672, driven by strong negative-ion-based neutral beams (N-NB), just before the onset so-called abrupt large event (ALE). It found that modes with toroidal mode numbers n = 2, 3, 4 can be destabilized, besides 1 studied previously. properties > sensitive to value plasma beta form ion distribution, so simulation conditions set up as...
The nonlinear interactions between shear Alfvén modes and tangentially injected beam ions in the 150–400 keV range are studied numerically realistic geometry for a JT-60U tokamak scenario. In Paper I, which was reported companion paper, recently developed orbit-based resonance analysis method used to track resonant frequency of fast during their evolution subject large magnetic electric drifts. Here, that is applied map wave-particle power transfer from canonical guiding center phase space...
Abstract The sensitivity of the growth and nonlinear evolution fast-ion-driven modes is examined with respect to choice particle boundary conditions, diffusion coefficients, fast ion gyroradii bulk compressibility. primary purpose this work justify parameters be used in self-consistent long-time simulations dynamics using global MHD-kinetic hybrid codes that include sources collisions. present study conducted for a scenario based on N-NB-driven JT-60U shot E039672, which subject abrupt large...
Resonances of high energy particles in magnetic confinement devices due to electromagnetic instabilities can strongly modify the distribution, leading a reduction fusion power and even discharge termination particle loss device walls through avalanche. The existence mode resonance depends on properties equilibrium, trajectories, perturbation harmonic content. Resonance location is function equilibrium field line helicity. Different methods for finding dependence are developed. resonances...