A5022982251- Magnetic confinement fusion research
- Superconducting Materials and Applications
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Solar and Space Plasma Dynamics
- Nuclear reactor physics and engineering
- Laser-induced spectroscopy and plasma
- Physics of Superconductivity and Magnetism
- Mechanical Engineering and Vibrations Research
- Semiconductor materials and devices
- Electric and Hybrid Vehicle Technologies
- Vehicle Dynamics and Control Systems
- Cellular and Composite Structures
- Atomic and Subatomic Physics Research
- Particle physics theoretical and experimental studies
- Silicon and Solar Cell Technologies
- Particle Detector Development and Performance
- Geomagnetism and Paleomagnetism Studies
- High-Energy Particle Collisions Research
- Atomic and Molecular Physics
- Advanced Data Storage Technologies
- Quantum Chromodynamics and Particle Interactions
Fraunhofer Institute for Chemical Technology
2020-2023
Jet Propulsion Laboratory
2021-2023
UNSW Sydney
2020-2023
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
2016-2018
Voestalpine (Austria)
2011-2016
Max Planck Institute of Quantum Optics
2016
Technical University of Munich
2016
General Atomics (United States)
2005-2014
Technische Universität Braunschweig
2012
Voestalpine (Brazil)
2011
Progress in the area of MHD stability and disruptions, since publication 1999 ITER Physics Basis document (1999 Nucl. Fusion 39 2137–2664), is reviewed. Recent theoretical experimental research has made important advances both understanding control tokamak plasmas. Sawteeth are anticipated baseline ELMy H-mode scenario, but tools exist to avoid or them through localized current drive fast ion generation. Active other instabilities will most likely be also required ITER. Extrapolation from...
A stochastic magnetic boundary, produced by an applied edge resonant perturbation, is used to suppress most large edge-localized modes (ELMs) in high confinement ($H$-mode) plasmas. The resulting $H$ mode displays rapid, small oscillations with a bursty character modulated coherent 130 Hz envelope. transport barrier and core are unaffected the despite threefold drop toroidal rotation. These results demonstrate that boundaries compatible may be attractive for ELM control next-step fusion tokamaks.
Large Type-I edge localized modes (ELMs) are completely eliminated with small n = 3 resonant magnetic perturbations (RMP) in low average triangularity, , plasmas and ITER similar shaped (ISS) plasmas, relevant collisionalities . Significant differences the RMP requirements properties of ELM suppressed found when comparing two triangularities. In ISS current required to suppress ELMs is approximately 25% higher than triangularity plasmas. It also that width q95 window for suppression smaller...
Intermittent plasma objects (IPOs) featuring higher pressure than the surrounding plasma, and responsible for ∼50% of E×BT radial transport, are observed in scrape off layer (SOL) edge DIII-D tokamak [J. Watkins et al., Rev. Sci. Instrum. 63, 4728 (1992)]. Conditional averaging reveals that IPOs, produced at a rate ∼3×103 s−1, positively charged also polarized, poloidal electric fields up to 4000 V/m. The IPOs move poloidally speeds 5000 m/s radially with E×BT/B2 velocities ∼2600 near last...
Intermittent plasma objects (IPOs), featuring higher pressure than the surrounding plasma, are responsible for ∼50% of E×BT radial transport in scrape off layer (SOL) Doublet III D (DIII-D) tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] L- and H-mode discharges. Conditional averaging reveals that IPOs positively charged feature internal poloidal electric fields up to 4000 V/m. The move radially with E×BT/B2 velocities ∼2600 m/s near last closed flux surface (LCFS), ∼330 wall. slow down...
As part of the ITER Design Review and in response to issues identified by Science Technology Advisory Committee, physics requirements were reviewed as appropriate updated. The focus this paper will be on recent work affecting design with special emphasis topics near-term procurement arrangements. This describe results on: sensitivity studies, poloidal field coil requirements, vertical stability, effect toroidal ripple thermal confinement, material choice heat load for plasma-facing...
Large sub-millisecond heat pulses due to Type-I edge localized modes (ELMs) have been eliminated reproducibly in DIII-D for periods approaching nine energy confinement times (τE) with small dc currents driven a simple magnetic perturbation coil. The current required eliminate all but few isolated ELM impulses during coil pulse is less than 0.4% of plasma current. Based on field line modelling, the fields resonate flux surfaces across most pedestal region (0.9 ⩽ ψN 1.0) when q95 = 3.7 ± 0.2,...
In this paper the manipulation of power deposition on divertor targets at DIII-D by application resonant magnetic perturbations (RMPs) for suppression large type-I edge localized modes (ELMs) is analysed. We discuss modification ELM characteristics RMP applied. It shown that width pattern in ELMy H-mode depends linearly deposited energy, whereas phase discharge those patterns are controlled externally induced perturbation. was also found heat transport due to small, plasma pedestal electron...
Recent DIII-D [J. L. Luxon et al., Nucl. Fusion 43, 1813 (2003)] experiments show a correlation between the extent of overlap magnetic islands induced in edge plasma by perturbation coils and complete suppression Type-I localized modes (ELMs) plasmas with ITER-like electron pedestal collisionality νe*∼0.1, flux surface shape low safety factor (q95≈3.6). With fixed amplitude n=3 resonant (RMP), ELM is obtained only finite window (q95) consistent maximizing component applied helical field....
We present the first evidence for existence of a neoclassical toroidal rotation driven in direction counter to plasma current by nonaxisymmetric, nonresonant magnetic fields. At high beta and with large injected neutral beam momentum, field torque slows down toward ``offset'' rate. With small is accelerated offset rotation, resulting improvement global energy confinement time. The observed magnitude, direction, radial profile are consistent theory predictions [A. J. Cole et al., Phys. Rev....
Operating ITER in the reference inductive scenario at design values of Ip = 15 MA and QDT 10 requires achievement good H-mode confinement that relies on presence an edge transport barrier whose pedestal pressure height is key to plasma performance. Strong gradients occur such conditions can drive magnetohydrodynamic instabilities resulting localized modes (ELMs), which produce a rapid energy loss from region facing components (PFC). Without appropriate control, heat loads PFCs during ELMs...
The application of static, non-axisymmetric, nonresonant magnetic fields (NRMFs) to high beta DIII-D plasmas has allowed sustained operation with a quiescent H-mode (QH-mode) edge and both toroidal rotation neutral beam injected torque near zero. Previous studies have shown that QH-mode can be accessed only if sufficient radial shear in the plasma flow is produced edge. In past experiments, this was using injection (NBI) provide torque. recent nearly completely replaced by from applied...
Abstract The non-linear reduced four-field RMHD model in cylindrical geometry was extended to include plasma rotation, neoclassical poloidal viscosity and two fluid diamagnetic effects. Interaction of the static resonant magnetic perturbations (RMPs) with rotating plasmas tokamaks studied. self-consistent evolution equilibrium electric field due RMP penetration is taken into account model. It demonstrated that pedestal region steep pressure gradients, mean flows perpendicular field, which...
H-mode operation is the choice for next-step tokamak devices based either on conventional or advanced physics. This choice, however, comes at a significant cost both and tokamaks because of effects edge-localized modes (ELMs). ELMs can produce erosion in divertor affect β limit reduced core transport regions needed operation. Recent experimental results from DIII-D have demonstrated new operating regime, quiescent which solves these problems. We achieved ELM-free yet has good density...
The authors' data indicate that the L-mode to H-mode transition in DIII-D tokamak is associated with sudden reduction anomalous, fluctuation-connected transport across outer midplane of plasma. In addition edge density and magnetic fluctuations observed at transition, radial electric field becomes more negative after transition. They have determined scaling power threshold various plasma parameters; roughly linear increase toroidal are particularly significant. Control ELM frequency duration...
The sensitivity of tokamak plasmas to very small deviations from the axisymmetry magnetic field |deltaB/B| approximately 10{-4} is well known. What was not understood until recently importance perturbation plasma equilibrium in assessing effects externally produced asymmetries field, even far a stability limit. DIII-D and NSTX experiments find that when deleterious are mitigated, external asymmetric often made stronger had an increased interaction with unperturbed equilibrium. This Letter...
Large Type-I edge-localized mode (ELM) heat pulses may limit the life of divertor targets in a burning plasma. Recent experiments show that pitch-resonant nonaxisymmetric magnetic perturbations plasma edge 0.0005 or less main field offer useful solution, but there is little room presently designed ITER for even small perturbation coils. We present proposed coil requirements ELM suppression, derived primarily from DIII-D suppression experiments. by calculated examples large arrays coils (e.g....
A study of three-dimensional (3D) perturbed magnetic field structures and transport for edge localized mode control experiments with resonant perturbations at DIII-D is presented. We focus on ITER-Similar Shape plasmas ITER relevant electron pedestal collisionalities . This performed in comparison results from TEXTOR-Dynamic Ergodic Divertor circular limiter plasmas. For both the structure analyzed vacuum paradigm—superimposing external RMP unperturbed equilibrium. TEXTOR L-mode this...
A low amplitude (δbr∕BT=1 part in 5000) edge resonant magnetic field perturbation with toroidal mode number n=3 and poloidal numbers between 8 15 has been used to suppress most large type I localized modes (ELMs) without degrading core plasma confinement. ELMs have suppressed for periods of up 8.6 energy confinement times when the safety factor q95 is 3.5 4. The are replaced by packets events (possibly II ELMs) small amplitude, narrow radial extent, a higher level density fluctuations,...
The first quantitative comparison of linear ideal magnetohydrodynamic (MHD) theory with external magnetic measurements the nonaxisymmetric plasma perturbation driven by long-wavelength fields in high-temperature tokamak plasmas is presented. yields good (within 20%) agreement for pressures up to ∼75% stability limit calculated without a conducting wall. For higher pressures, MHD model tends overestimate perturbed field indicating increasing importance stabilizing nonideal effects.
A detailed experiment-theory comparison reveals that linear ideal MHD theory is in quantitative agreement with external magnetic and internal soft x-ray measurements of the plasma response to externally applied non-axisymmetric fields over a broad range beta rotation. This result represents significant step toward goal advancing understanding three-dimensional tokamak equilibria. Both show driven perturbation increases linearly perturbation, suggesting relevance models. The are made at...
In-vessel, non-axisymmetric, control coils have proven to be an important option for mitigating and suppressing edge-localized modes (ELMs) in high performance operating regimes on a growing number of tokamaks. Additionally, in-vessel non-axisymmetric ELM coil is being considered the ITER baseline design. In preparing initial operation this set, comprehensive study was carried out characterize linear superposition 3D vacuum magnetic field, produced by coil, series equilibria representing...
Using resonant magnetic perturbations with toroidal mode number n = 3, we have produced H-mode discharges without edge localized modes (ELMs) which run constant density and radiated power for periods up to about 2550 ms (17 energy confinement times). These ELM suppression results are achieved at pedestal collisionalities close those desired next step burning plasma experiments such as ITER provide a means of eliminating the rapid erosion divertor components in machines could be caused by...