A5026533721- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Solar and Space Plasma Dynamics
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Nuclear Physics and Applications
- Plasma Diagnostics and Applications
- Laser-induced spectroscopy and plasma
- Fluid Dynamics and Turbulent Flows
- Advanced Data Storage Technologies
- Geophysics and Gravity Measurements
- Dust and Plasma Wave Phenomena
- Nuclear Engineering Thermal-Hydraulics
- Ocean Waves and Remote Sensing
- COVID-19 Clinical Research Studies
- Anomaly Detection Techniques and Applications
- Ion-surface interactions and analysis
- Quantum chaos and dynamical systems
- Atomic and Molecular Physics
- earthquake and tectonic studies
- Physics of Superconductivity and Magnetism
- Mass Spectrometry Techniques and Applications
Culham Centre for Fusion Energy
2002-2024
Culham Science Centre
2002-2024
ITER
2015-2024
General Atomics (United States)
2020
Donghua University
2020
Max Planck Institute for Plasma Physics
1998-2017
Max Planck Society
1998-2017
Max Planck Innovation
2002-2017
Max Planck Institute for Plasma Physics - Greifswald
2006
University of Nottingham
1998
Type-I edge-localized modes (ELMs) have been mitigated at the JET tokamak using a static external $n=1$ perturbation field generated by four error correction coils located far from plasma. During application of ELM frequency increased factor 4 and amplitude ${\mathrm{D}}_{\ensuremath{\alpha}}$ signal decreased. The energy loss per normalized to total stored energy, $\ensuremath{\Delta}W/W$, dropped values below 2%. Transport analyses shows no or only moderate (up 20%) degradation confinement...
The area of energetic particle (EP) physics in fusion research has been actively and extensively researched recent decades. progress achieved advancing understanding EP substantial since the last comprehensive review on this topic by Heidbrink Sadler (1994 Nucl. Fusion 34 535). That coincided with start deuterium–tritium (DT) experiments Tokamak Test Reactor (TFTR) full scale alphas studies.
Gyrokinetic simulations of the fishbone instability in DIII-D tokamak plasmas find that self-generated zonal flows can dominate nonlinear saturation by preventing coherent structures from persisting or drifting energetic particle phase space when mode frequency down-chirps. Results simulation with agree quantitatively, for first time, experimental measurements amplitude and transport. Moreover, fishbone-induced are likely responsible formation an internal transport barrier was observed after...
The onset of a neoclassical tearing mode (NTM) depends on the existence large enough seed island. It is shown in Joint European Torus that NTMs can be readily destabilized by long-period sawteeth, such as obtained sawtooth stabilization from ion-cyclotron heating or current drive. This has important implications for burning plasma scenarios, alpha particles strongly stabilize sawteeth. also that, adding and drive just outside inversion radius, sawteeth are destabilized, resulting shorter...
MAST plasmas with a safety factor above unity and profile either weakly reversed shear or broad low-shear regions, regularly exhibit long-lived saturated ideal magnetohydrodynamic (MHD) instabilities. The toroidal rotation is flattened in the presence of such perturbations fast ion losses are enhanced. These modes, distinguished as by notable lack islands signs reconnection, driven unstable approaches unity. This could be significance for advanced scenarios, hybrid scenarios which aim to...
The ITER Integrated Modelling & Analysis Suite (IMAS) will support both plasma operation and research activities on the tokamak experiment.The IMAS be accessible to all members as a key tool for scientific exploitation of ITER.The backbone infrastructure is standardized, machine-generic data model that represents simulated experimental with identical structures.The other outcomes design prototyping phase are set tools access integrated modelling workflows, well first simulators workflows...
This paper discusses the behaviour and consequences of expected populations energetic ions in ITER plasmas. It begins with a careful analytic numerical consideration stability Alfvén Eigenmodes 15 MA baseline scenario. The threshold is determined by balancing ion drive against dominant damping mechanisms it found that only outer half plasma (r/a>0.5) can fast overcome thermal Landau damping. spite reduced numbers alpha-particles beam this region but means any Eigenmode-induced...
Alfv\'en spectra in a reversed-shear tokamak plasma with population of energetic ions exhibit quasiperiodic pattern primarily upward frequency sweeping (Alfv\'en cascade). Presented here is an explanation for such asymmetric behavior which involves finding new particle mode localized around the point zero magnetic shear.
Persistent rapid up and down frequency chirping modes with a toroidal mode number of zero (n = 0) are observed in the JET tokamak when energetic ions, range several hundred keV, created by high field side ion cyclotron resonance heating. Fokker–Planck calculations demonstrate that heating method enables formation an energetically inverted distribution which supplies free energy for ions to excite related geodesic acoustic mode. The large shifts this attributed phase space structures whose...
Experiments designed for generating internal transport barriers in the plasmas of Joint European Torus [JET, P. H. Rebut et al., Proceedings 10th International Conference, Plasma Physics and Controlled Nuclear Fusion, London (International Atomic Energy Agency, Vienna, 1985), Vol. I, p. 11] reveal cascades Alfvén perturbations with predominantly upward frequency sweeping. These experiments are characterized by a hollow plasma current profile, created lower hybrid heating drive before main...
The formation of internal transport barriers (ITBs) has been experimentally associated with the presence rational q surfaces in both JET and ASDEX Upgrade. triggering mechanisms are related to occurrence magneto-hydrodynamic (MHD) instabilities such as mode coupling fishbone activity. These events could locally modify poloidal velocity increase transiently shearing rate values comparable linear growth ion temperature gradient modes. For reversed magnetic shear scenarios, ITB emergence occurs...
Recent experiments on JET have shown that type-I edge localized modes (ELMs) can be controlled by the application of static low n = 1 external magnetic perturbation fields produced four error field correction coils (EFCC) mounted far away from plasma between transformer limbs. When an with amplitude a few mT at (the normalized poloidal flux, ?, is larger than 0.95) applied during stationary phase ELMy H-mode plasma, ELM frequency rises ~30?Hz up to ~120?Hz. The energy loss per total stored...
Remarkable progress has been made in diagnosing energetic particle instabilities on presentday machines and establishing a theoretical framework for describing them.This overview describes the much improved diagnostics of Alfvén modelling tools developed world-wide, discusses interpreting observed phenomena.A multi-machine comparison is presented giving information performance both different plasma conditions outlining expectations ITER based our present knowledge.
This paper summarizes the physical principles behind novel three-ion scenarios using radio frequency waves in ion cyclotron range of frequencies (ICRF). We discuss how to transform mode conversion electron heating into a new flexible ICRF technique for and fast-ion generation multi-ion species plasmas. The theoretical section provides practical recipes selecting plasma composition realize scenarios, including two equivalent possibilities choice resonant absorbers that have been identified....
Plasma configurations with shear reversal are prone to the excitation of unusual Alfvén eigenmodes by energetic particles. These modes exhibit a quasiperiodic pattern predominantly upward frequency sweeping (Alfvén cascades) as safety factor q changes in time. This work presents theory that employs two complementary mechanisms for establishing cascades: (1) nonstandard adiabatic response particles large orbits and (2) toroidal magnetohydrodynamic effects second-order inverse aspect ratio....
Recent experiments at ASDEX Upgrade have achieved advanced scenarios with high βN (>3) and confinement enhancement over ITER98(y, 2) scaling, HH98y2 = 1.1–1.5, in steady state. These discharges been obtained a modified divertor configuration for Upgrade, allowing operation higher triangularity, changed neutral beam injection (NBI) system, more tangential, off-axis deposition. The figure of merit, βNHITER89-P, reaches up to 7.5 several seconds plasmas approaching stationary conditions....
Dedicated experiments in the DIII-D tokamak [J. L. Luxon, Nucl. Fusion, 42, 614 (2002)], Joint European Torus (JET) [P. H. Rebut, R. J. Bickerton, and B. E. Keen, Fusion 25, 1011 (1985)], National Spherical Experiment (NSTX) [M. Ono, S. M. Kaye, Y.-K. Peng et al., 40, 557 (2000)] reveal commonalities of resistive wall mode (RWM) stabilization by sufficiently fast toroidal plasma rotation devices different size aspect ratio. In each device weakly damped n=1 RWM manifests itself resonant field...
In 2003, the performance of 'hybrid' regime was successfully validated in JET experiments up to βN = 2.8 at low toroidal field (1.7 T), with plasma triangularity and normalized Larmor radius (ρ*) corresponding identical ASDEX Upgrade discharges. Stationary conditions have been achieved fusion figure merit ( ) reaching 0.42 q95 3.9. The discharges show similar MHD, edge current profile behaviour, when compared Upgrade. addition, extended hybrid scenario operation higher 2.4 T lower ρ* towards...
The fast-ion distribution from third harmonic ion cyclotron resonance frequency (ICRF) heating on the Joint European Torus is studied using neutron emission spectroscopy with time-of-flight spectrometer TOFOR. energy dependence of fast deuteron function inferred measured spectrum neutrons born in DD fusion reactions, and compared theoretical models for ICRF heating. Good agreements between modelling measurements are seen clear features function, that due to finite Larmor radius resonating...
The detection of fast particle-driven waves in the ion cyclotron frequency range (ion emission or ICE) could provide a passive, non-invasive diagnostic confined and escaping particles (fusion α-particles beam ions) ITER, would be compatible with high radiation environment deuterium–tritium plasmas that device. Recent experimental results from ASDEX Upgrade DIII-D demonstrate efficacy ICE as different species losses, while recent particle-in-cell (PIC) hybrid simulations more exact comparison...
Abstract In the initial stages of ITER operation, ELM mitigation systems need to be commissioned. This requires controlled flat-top operation in type-I ELMy H-mode regimes. Hydrogen or helium plasma discharges are used exclusively these ensure negligible production neutrons from fusion reactions. With expected higher L-H power threshold hydrogen and plasmas compared corresponding D D/T plasmas, it is uncertain whether available auxiliary sufficient operate stable H-mode. has been...
Abstract We review the physics of energetic particles (EPs) in magnetically confined burning fusion plasmas with focus on advances since last update ITER Physics Basis (Fasoli et al 2007 Nucl. Fusion 47 S264). Topics include basic EP physics, generation, diagnostics EPs and instabilities, interaction thermal plasma EP-driven particle modes (EPMs), turbulence, linear nonlinear stability simulation instabilities EPMs, 3D effects, scenario optimization strategies based phase-space control,...
A microwave interferometry technique is applied for the first time detecting a discrete spectrum of Alfvén cascade (AC) eigenmodes excited with fast ions in reversed magnetic shear plasmas Joint European Torus. The measurements plasma density perturbations associated ACs show an unprecedented frequency and resolution superior to that obtained external coils. are used monitoring evolution safety factor rational surfaces region maximum current.