A5042964509- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Laser-induced spectroscopy and plasma
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Atomic and Molecular Physics
- Solar and Space Plasma Dynamics
- Nuclear reactor physics and engineering
- X-ray Spectroscopy and Fluorescence Analysis
- Laser Design and Applications
- Spectroscopy and Laser Applications
- Fault Detection and Control Systems
- Particle Accelerators and Free-Electron Lasers
- Lightning and Electromagnetic Phenomena
- GNSS positioning and interference
- Advancements in Photolithography Techniques
- Plasma and Flow Control in Aerodynamics
- Quantum chaos and dynamical systems
- Fusion and Plasma Physics Studies
- Fluid Dynamics and Turbulent Flows
Eindhoven University of Technology
2015-2024
Ghent University
2006-2018
Ghent University Hospital
2017
Fusion (United States)
2010-2015
Fusion Academy
2010-2015
Institute for Atomic and Molecular Physics
2001-2013
Dutch Institute for Fundamental Energy Research
2013
Forschungszentrum Jülich
1995-2008
Ioffe Institute
2008
Culham Science Centre
2008
The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D temperature dynamics with high spatial and temporal resolution. An overview technical experimental properties system is presented. These are illustrated by edge localized mode reversed shear Alfvén eigenmode, showing both advantage having a two-dimensional (2D) measurement, as well some limitations measurements. Furthermore, application singular value decomposition powerful...
The main challenge for the Thomson scattering (TS) diagnostic on TEXTOR tokamak is detailed study of fast plasma events at a high spatial resolution and repetition rate measurements. uses intra-cavity probing with repetitively pulsed ruby laser CMOS camera as detectors. Since 2004, TS system has been gradually systematically enhanced measurements events. For that it recently upgraded to obtain multi-pass configuration. Two spherical mirrors have installed force beam probe specified number...
Abstract In this work, we provide the first 2D spatially resolved description of radiative detachment in MAST-U Super-X L-mode divertor plasmas. The magnetic configuration was designed to achieve reduced heat- and particle loads at target compared conventional exhaust solutions. We use filtered camera imaging reconstruct emissivity profiles poloidal plane for multiple atomic molecular emission lines bands. A set deuterium fuelling scans is discussed that, together, span attached deeply...
Stationary high energy confinement is observed on TEXTOR-94 for times limited only by the flux swing of transformer using strong edge radiation cooling. Necessary tools are feedback control radiated power and plasma content. At highest densities obtained (up to 1.2 Greenwald limit), exceeds edge-localized-mode-free H-mode scaling ITERH93-P more than 20%. β limits reached with fH89/qa≈0.6. No detrimental effect seeded impurity seen. These discharges meet many conditions necessary a fusion...
An experimental study of the generation runaway electrons in TEXTOR has been performed. From infrared synchrotron radiation emitted by relativistic electrons, number can be obtained as a function time. In low density discharges (ne < 1 × 1019 cm-3) runaways are created throughout discharge and not predominantly in-the startup phase, exponential increase population ongoing production after is increased, it concluded that secondary generation, i.e. creation through close collisions already...
Extensive analysis of disruptions in JET has helped advance the understanding trends disruption-generated runaway electrons. Tomographic reconstruction soft x-ray emission made possible a detailed observation magnetic flux geometry evolution during disruptions. With aid and hard diagnostics electrons have been detected at very beginning A study electron parameters shown that an approximate upper bound for conversion efficiency pre-disruptive plasma currents into runaways is about 60% over...
Runaway electrons represent a serious problem for the reliable operation of future experimental tokamak ITER.Due to multiplication factor exp(50) in avalanche even few seed runaway will result beam high energetic that is able damage machine.Thus suppression task importance, which reason we present here systematic study following massive gas injection TEXTOR.Argon can cause generation runaways carrying up 30% initial plasma current, while disruptions triggered by helium or mixtures argon (5,...
The suppression of (neoclassical) tearing modes is great importance for the success future fusion reactors like ITER. Electron cyclotron waves can suppress islands, both by driving noninductive current in island region and heating island, causing a perturbation to Ohmic plasma current. This Letter reports on experiments TEXTOR tokamak, investigating effect heating, which usually neglected. unique set tools available TEXTOR, notably dynamic ergodic divertor create islands with fully known...
The Charge Exchange Recombination Spectroscopy (CXRS) diagnostic has become a routine on almost all major high temperature fusion experimental devices. For the optimized stellarator Wendelstein 7-X (W7-X), highly flexible and extensive CXRS been built to provide high-resolution local measurements of several important plasma parameters using recently commissioned neutral beam heating. This paper outlines design specifics W7-X system gives examples initial results obtained, including typical...
A population of 30 MeV runaway electrons in the TEXTOR tokamak is diagnosed by their synchrotron emission. During pellet injection a large fraction lost within 600 \ensuremath{\mu}s. This rapid loss attributed to stochastization magnetic field. The remaining runaways form narrow, helical beam at $q=1$ drift surface. radial and poloidal diffusion this extremely slow, $D<0.02$ ${\mathrm{m}}^{2}$/s. fact that survives period stochastic field shows chaotic sea big islands must remain intact.
The first results of the Dynamic Ergodic Divertor in TEXTOR, when operating m/n=3/1 mode configuration, are presented. deeply penetrating external magnetic field perturbation this configuration increases toroidal plasma rotation. Staying below excitation threshold for m/n=2/1 tearing mode, rotation is always direction current, even if projection rotating opposite direction. observed consistent with a radial electric field, generated by an enhanced electron transport ergodic layers near...
Controlled experiments on the suppression of m/n = 2/1 tearing mode with electron cyclotron heating and current drive in TEXTOR are reported. The was produced reproducibly by an externally applied rotating perturbation field, allowing a systematic study its suppression. Heating inside island is shown to be dominant mechanism these experiments. An extrapolation findings ITER indicates that projected system for could significantly more effective than present estimates indicate, which only...
The motional Stark effect (MSE) diagnostic is used to measure the radial magnetic pitch angle profile in neutral beam heated plasmas. This information calculate safety factor, q, with equilibrium reconstruction codes such as EFIT. MSE important during active shaping of q optimize confinement and stability, it has become a key high performance tokamaks. A multichord photo-elastic modulator (PEM) based system being developed for real-time plasma current control Korea Superconducting Tokamak...
Abstract Radial impurity density profiles in two Wendelstein 7-X (W7-X) experiments heated by neutral beam injection (NBI) are analyzed with respect to their transport properties. Local densities derived from charge exchange reactions the W7-X NBI system using simulated cross-validated emission spectroscopy. Impurity of argon and carbon found show an evolving central accumulation inside half radius. The properties underlying assessed one-dimensional code pySTRAHL. Comparisons between...
Runaway generation during a major disruption has been observed in TEXTOR. Measurements of the synchrotron radiation yielded number, energy and pitch angle runaways. A simple model, which assumes that runaways take over current density centre discharge, successfully describes these measurements. This model is applied to JET ITER. One interesting result it could be favourable for ITER have high runaway production. leads lower less damage. Quantitative predictions are sensitive value parameter...
The radiative improved (RI) mode is a tokamak regime offering many attractive reactor features. In the article, RI of TEXTOR-94 shown to follow same scaling as linear ohmic confinement and thus identified one most fundamental operational regimes. current understanding derived from experiments modelling conditions necessary for sustaining reviewed, are mechanisms leading L-RI transition. article discusses compatibility high impurity seeding with low central power density burning reactor, well...
With the dynamic ergodic divertor in TEXTOR fundamental effects of coupling external magnetic field perturbations to confined plasma have been studied. The non-linear between (m/n = 12/4) and internal modes 3/1) has investigated. critical perturbation for excitation an m/n 2/1 tearing mode depends not only on magnitude but also direction toroidal angular momentum input by neutral beam injection (NBI). Below threshold this a spin-up observed, which strength field. It is independent both...
For fusion reactors, based on the principle of magnetic confinement, it is important to avoid so-called islands or tearing modes. They reduce confinement and can be cause major disruptions. One class that perturbation field driven This can, for example, intrinsic error field. Theoretical work predicts a strong relationship between plasma rotation excitation Experimentally, theory mode has been confirmed several tokamaks. In those experiments, however, control over velocity direction,...
Several collisional–radiative (CR) models (Anderson et al 2000 Plasma Phys. Control. Fusion 42 781–806, Hutchinson 2002 44 71–82, Marchuk 2008 Rev. Sci. Instrum. 79 10F532) have been developed to calculate the attenuation and population of excited states hydrogen or deuterium beams injected into tokamak plasmas. The datasets generated by these CR are needed for modelling beam ion deposition (excited) densities in current experiments, reliability data will be crucial obtain helium ash on ITER...
In present day tokamaks runaway electrons can be confined long enough to gain energies in the order of several tens megaelectron volts. At these synchrotron radiation is emitted infrared wavelength range which easily detected by thermographic cameras. The spectral features this are reviewed. On TEXTOR-94 a diagnostic exploiting has been developed and presented here. It shown how deduce parameters like energy, pitch angle, current beam radius from measurements. Based on experience at...
An overview of the results obtained so far for radiative I-mode regime on upgraded Torus Experiment Technology Oriented Research (TEXTOR-94) [Proceedings 16th IEEE Symposium Fusion Engineering (Institute Electrical and Electronics Engineers, Piscataway, NJ, 1995), Vol. 1, p. 470] is given. This under quasistationary conditions with edge neon seeding in a pumped limiter tokamak circular cross section. It combines high confinement β (up to normalized beta, βn=2) low q values (down qa=2.8)...
Duplex Doppler ultrasound (US) was used in 21 consecutive patients with renal masses, including carcinoma (n = 9), metastases 6), lymphoma 4), angiomyolipoma 1), and sarcoma 1). Seven of the nine carcinomas had shifts 4 kHz or more were hypervascular vascular. These seven masses significantly higher (P less than .001) all other malignant two avascular cell carcinomas. Correlation angiographic findings suggests that high-frequency signals associated arteriovenous shunts. Detection high shift...
The need for quantitative evaluation of complex line emission spectra as observed in hot fusion plasmas initiated a challenging development sophisticated interpretation tools based on integrating advanced atomic modelling with detailed treatment the plasma environment. successful merging two worlds has led to routine diagnostic procedures which have contributed enormously understanding underlying processes and also wide acceptance spectroscopy reliable method. In this paper three...
The ergodization of the magnetic field lines imposed by dynamic ergodic diverter (DED) in TEXTOR can lead both to confinement improvement and deterioration. cases substantial are resonant ways related particular conditions which flux tubes starting at $X$ points induced islands connected with wall. This opening process is a characteristic modification heat deposition pattern divertor target plate leads increase steepening core plasma density pressure. tentatively attributed electric...