A5053717846- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Laser-Plasma Interactions and Diagnostics
- Superconducting Materials and Applications
- Solar and Space Plasma Dynamics
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Spectroscopy and Quantum Chemical Studies
- Photochemistry and Electron Transfer Studies
- Fluid Dynamics and Turbulent Flows
- Molecular spectroscopy and chirality
- Nuclear Materials and Properties
- Catalytic Processes in Materials Science
- Parallel Computing and Optimization Techniques
- Ion-surface interactions and analysis
- Aerosol Filtration and Electrostatic Precipitation
- Mathematics, Computing, and Information Processing
- Magnetic properties of thin films
- Spectroscopy and Laser Applications
- CO2 Reduction Techniques and Catalysts
- Scientific Research and Discoveries
- Human-Animal Interaction Studies
- Sports, Gender, and Society
Forschungszentrum Jülich
2012-2025
Plasma (Russia)
2019-2021
Royal Military Academy
2020
Lawrence Livermore National Laboratory
2016
Cologne Business School
2013-2014
Fusion for Energy
2013
European University of Applied Sciences
2013
Universität Innsbruck
2009
Kurchatov Institute
2008
University of Duisburg-Essen
1995
Abstract Results from three-dimensional modeling of plasma edge transport and plasma–wall interactions during application resonant magnetic perturbation (RMP) fields for control edge-localized modes in the ITER standard 15 MA Q = 10 H-mode are presented. The full 3D fluid kinetic neutral code EMC3-EIRENE is used modeling. Four characteristic perturbed topologies considered discussed with reference to axisymmetric case without RMP fields. Two field amplitudes at half ELM coil current...
Abstract A review is given on the highlights of a scatter-shot approach developing machine-learning methods and artificial neural networks based fast predictors for application to fusion exhaust. The aim enable facilitate optimized improved modeling allowing more flexible integration physics models in light extrapolations towards future devices. project encompasses various research objectives: (a) developments surrogate model power & particle exhaust plants; (b) assessments...
Systematic measurements on the edge turbulence and turbulent transport have been made by Langmuir probe arrays TEXTOR under various static Dynamic Ergodic Divertor (DED) configurations. Common features are observed. With DED, in ergodic zone local flux reverses sign from radially outwards to inwards. The properties profoundly modified energy redistribution frequency spectra suppression of large scale eddies. fluctuation poloidal phase velocity changes direction electron ion diamagnetic...
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...
A cross-comparison and verification of state-of-the-art European codes describing gradient-driven plasma turbulence in the core edge regions tokamaks, carried out within EFDA Task Force on Integrated Tokamak Modelling, is presented. In case ion temperature gradient (ITG) driven with adiabatic electrons (neglecting trapped particles), good/reasonable agreement found between various gyrokinetic/gyrofluid codes. The main physical reasons for some deviations observed nonlocal simulations are...
The influence of the magnetic ergodization on edge turbulence and turbulence-induced transport has been investigated by Langmuir probes in TEXTOR under three different static DED configurations. Common features are observed. With DED, equilibrium profiles altered resultant positive Er is agreement with modelling. In ergodic zone, potential fluctuations strongly reduced local turbulent flux changes direction from radially outwards to inwards. same properties profoundly modified energy...
The plasma response on externally applied resonant magnetic field perturbations is studied by means of numerical simulations. It shown that dependent collisionality and perturbation strength, currents build up which can compensate the external field. These are accompanied out-of-phase poloidal flows at surfaces. With an increasing screening decreases a certain level, vacuum approximation holds for total
In a tokamak plasma the maximum achievable density is limited. A too high will result in violent end of discharge. Two types limit disruption can be distinguished: (a) impure and moderately heated discharges, if radiative power exceeds input power, (b) clean, auxiliary where Greenwald encountered. It has been found that TEXTOR-94 these two limits differ by instability boundary, which preceeds disruption. symmetric mantle detachment are observed prior to first type, while MARFE precursor....
The dynamic ergodic divertor (DED), a new concept of the divertor, is presently installed for TEXTOR tokamak. Beside conventional operation DED also permits with rotating magnetic field which allows, in particular, to broaden heat deposition pattern on plates. Since its first proposal 1996 structure field, especially, onset zone lines and related transport DED-operation has been extensively studied using different theoretical numerical methods. New methods study line mapping have developed....
The magnetic field penetration process into a magnetized plasma is of basic interest both for physics and astrophysics. In this context special measurements on the amplification are performed by Hall probe dynamic ergodic divertor (DED) TEXTOR tokamak data interpreted two-fluid model. It observed that growth forced reconnection rotating DED accompanied change fluid rotation. differential rotation frequency between plays an important role in excitation tearing modes. momentum input from to...
Experiments to investigate transport properties under the influence of dynamic ergodic divertor (DED) on TEXTOR are discussed. Relativistic runaway electrons applied for studying ergodization such as enhanced loss. The causes an loss rate; this is higher low relativistic than highly ones, in good agreement with particle orbit mapping. Edge can be controlled by DED perturbation: limiter H-mode plasmas ELM-like and heat bursts associated formation edge pressure gradients mitigated 6/2...
The electrostatic potential and density fluctuations have been measured at the edge of TEXTOR tokamak by two toroidally distant Langmuir probe arrays.The geodesic acoustic mode (GAM) zonal flows are observed in with a toroidal poloidal symmetric structure.The GAM frequency, , changes monotonically local temperature is close to frequency-dispersion predicted theories.Bispectral analysis shows clear nonlinear coupling between broadband ambient turbulence.The packet has narrow radial extent ≃...
Transport properties of the edge ergodized plasma in TEXTOR-DED (Finken K H and Wolf G 1997 Fusion Eng. Des. 37 337) are studied using 3D transport code package, EMC3-EIRENE, prior to forthcoming experimental campaign. EMC3 solves steady-state fluid equations mass, momentum energy, almost any arbitrary magnetic bounding surface configurations. It is iteratively coupled with EIRENE, a kinetic neutral particle code. Two different levels ergodization have been selected order assess additional...
An important operational range for TEXTOR-DED is the case of a high ergodization at plasma edge. Under these conditions, edge magnetic field forms proper ergodic layer and laminar zone. The zone established by lines which intersect wall elements after only few toroidal turns (open system). For this, both heat particle transport in are dominated shows well defined structure compared with that layer. present analysis regions containing connection lengths corresponding to one or two poloidal...
The expression for the Coulomb collision term in Fokker-Planck form is revised and generalized to case of interaction trace impurity ions with a fluid-like background plasma. velocity distribution assumed as Maxwellian 13 moment expansion, parameters determined from fluid consideration. impurities are described framework linear drift kinetic test particle model. new suitable Monte Carlo procedures provides both correct treatment thermalization particles an accurate description effects on...
Recently, the dynamic ergodic divertor (DED) of TEXTOR has been studied in an m/n = 3/1 set-up which is characterized by a relatively deep penetration perturbation field. The field creates (a) helical divertor, (b) pattern and/or (c) excitation tearing modes, depending on whether DED current static, rotating co-current direction or counter-current direction. Characteristic properties such as high recycling regime enhanced shielding have studied. A strong effect ergodization spin up plasma...
The turbulent blob transport in the tokamak edge and its structural changes perturbed magnetic configurations like islands ergodic structures is studied by means of numerical simulations. An explicit finite-difference algorithm for treating three-dimensional plasma fluid turbulence models presented described detail. For an unperturbed equilibrium results show appearance density blobs vicinity last closed flux surface. In presence perturbation strong suppression amplitudes local reversal...
The error-field penetration process of the dynamic ergodic divertor (DED) on TEXTOR tokamak has been investigated analytically in terms a single fluid MHD model with finite plasma resistivity and viscosity cylindrical geometry. linear produces localization induced current at resonance surface predicts vortex structure velocity field near layer. Moreover, effects Alfvén for are identified by two peaks radial profiles perturbed toroidal magnetic flux when relative rotation between DED rotating...
This paper attempts to give an overview on the study of geodesic acoustic mode (GAM) and related velocity oscillation zonal flow (ZF) at TEXTOR. The reported results are obtained from poloidal cross correlation reflectometry. advantages diagnostic combined with a multi-antenna set-up, as it is installed TEXTOR, shortly reviewed compared other diagnostics used in experiments GAMs.
During the static 6/2 Dynamic Ergodic Divertor experiments in TEXTOR, a significant influence of edge resonant magnetic perturbation (RMP) on turbulent blob transport scrape-off layer (SOL) has been observed. In ohmic discharges without RMP, blobs extend 4–5 cm deep into SOL with radially outward moving speed about 1 km s −1 and hence constitute strong outflow mass. With application amplitudes their velocity are both reduced, resulting reduction SOL. The effect RMP is found to be robust...
Abstract Rotating resonant magnetic perturbation (RMP) fields impose a characteristic modulation to the edge electron density n e ( r , t ) and temperature T fields, which depends on relative rotation f rel between external RMP field plasma fluid. The measured in / = 0.9–1.05) of TEXTOR L-mode plasmas are close correlation with local vacuum topology for low −0.2 kHz. In comparison 3D neutral transport code EMC3-Eirene, this provides substantial experimental evidence that level high...
Three-dimensional global drift fluid simulations are carried out to analyze coherent plasma structures appearing in the NAGDIS-II linear device (nagoya divertor Simulator-II). The numerical reproduce several features of intermittent spiraling observed, for instance, statistical properties, rotation frequency, and frequency expulsion. detailed inspection three-dimensional dynamics allows identify key mechanism behind formation these events. resistive coupling between electron pressure...