G. Szepesi
A5056467106- Magnetic confinement fusion research
- Fusion materials and technologies
- Analytical Chemistry and Chromatography
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Superconducting Materials and Applications
- Nuclear reactor physics and engineering
- Particle accelerators and beam dynamics
- Heat Transfer and Optimization
- Plasma Diagnostics and Applications
- Combustion and Detonation Processes
- Chromatography in Natural Products
- Microfluidic and Capillary Electrophoresis Applications
- Risk and Safety Analysis
- Heat Transfer Mechanisms
- Solar and Space Plasma Dynamics
- Analytical Methods in Pharmaceuticals
- Refrigeration and Air Conditioning Technologies
- Process Optimization and Integration
- Cyclone Separators and Fluid Dynamics
- Radiative Heat Transfer Studies
- Aerodynamics and Fluid Dynamics Research
- Hungarian Social, Economic and Educational Studies
- Engineering Applied Research
- Fluid Dynamics and Mixing
University of Miskolc
2015-2024
Culham Science Centre
2014-2024
Culham Centre for Fusion Energy
2011-2024
United Kingdom Atomic Energy Authority
2020-2024
Royal Military Academy
2020
Max Planck Society
2018
Max Planck Institute for Plasma Physics
2018
Institute of Plasma Physics
2017
University of Warwick
2009-2014
Mahidol University
2012
Operation and exploitation of present future Tokamak reactors require advanced scenario modeling in order to optimize engineering parameters the design phase as well physics performance during phase. The simulation scenarios involves simultaneous different regions reactor, characterized by symmetries, predict quantities such particle energy confinement, fusion yield, power deposited on wall, wall load from fast particles. JINTRAC is a system 25 interfaced Tokamak-physics codes for integrated...
Toroidal momentum transport mechanisms are reviewed and put in a broader perspective. The generation of finite flux is closely related to the breaking symmetry (parity) along field. argument allows for systematic identification possible mechanisms. Those that appear lowest order normalized Larmor radius (the diagonal part, Coriolis pinch, E × B shearing, particle flux, up–down asymmetric equilibria) reasonably well understood. At higher order, expected be importance plasma edge, theory still...
Quasilinear turbulent transport models are a successful tool for prediction of core tokamak plasma profiles in many regimes. Their success hinges on the reproduction local nonlinear gyrokinetic fluxes. We focus significant progress quasilinear model QuaLiKiz [C. Bourdelle et al. 2016 Plasma Phys. Control. Fusion 58 014036], which employs an approximated solution mode structures to significantly speed up computation time compared full linear solvers. Optimization dispersion relation algorithm...
Since the end of 2005 most plasma–wall interaction experiments on FTU have been focused possible use liquid lithium as plasma facing material. Liquid limiter is an active method to deposit, during discharge, a film walls with prolonged beneficial effects. Reliable operation very clean plasmas, low wall particle recycling, spontaneous peaking density profile for line-averaged values obtained. These results allowed us extend limit highest value so far obtained ( at I p = 0.7 MA and B T 7.1 T,...
New H-mode regimes with high confinement, low core impurity accumulation, and small edge-localized mode perturbations have been obtained in magnetically confined plasmas at the Joint European Torus tokamak. Such are achieved by means of optimized particle fueling conditions input power, current, magnetic field, which lead to a self-organized state strong increase rotation ion temperature decrease edge density. An interplay between plasma regions leads reduced turbulence levels outward...
Abstract The work describes the pedestal structure, transport and stability in an effective mass ( A eff ) scan from pure deuterium to tritium plasmas using a type I ELMy H-mode dataset which key parameters that affect behaviour (normalized pressure, ratio of separatrix density density, ion Larmor radius, collisionality rotation) are kept as constant possible. Experimental results show significant increase at top with increasing , modest reduction temperature pressure. variations heights...
Abstract As part the DTE2 campaign in JET tokamak, we conducted a parameter scan T and D-T complementing existing pulses H D. For different main ion masses, type-I ELMy H-modes at fixed plasma current magnetic field can have pedestal pressure varying by factor of 4 total changing from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>β</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">N</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo>...
Abstract In the paper we present an overview of interpretive modelling a database JET-ILW 2021 D-T discharges using TRANSP code. The main aim is to assess our capability computationally reproducing fusion performance various plasma scenarios different external heating and mixtures, understand driving mechanisms. We find that simulations confirm general power-law relationship between increasing power output, which supported by absolutely calibrated neutron yield measurements. A comparison...
Nondiffusive anomalous momentum transport in toroidal plasmas occurs through symmetry breaking mechanisms. In this paper the contribution of sheared E×B flows to parallel [R. R. Dominguez and G. M. Staebler, Phys Fluids B 5, 3876 (1993)] is investigated with nonlinear gyrokinetic simulations geometry. The background perpendicular shear treated independently from velocity isolate a nondiffusive, nonpinch flux. It found that size term depends strongly on magnetic shear, sign reversing for...
The interaction between small scale turbulence (of the order of ion Larmor radius) and mesoscale magnetic islands is investigated within gyrokinetic framework. Turbulence, driven by background temperature density gradients, over nonlinear mode coupling, pumps energy into long wavelength modes, can result in an electrostatic vortex that coincides with island. strength strongly enhanced modified plasma flow response connected change topology, transport it generates compete parallel motion...
Tokamak experiments operate with a rotating plasma, toroidal velocity which can be driven externally but also arise spontaneously. In the frame that corotates effects of centrifugal force are felt through drift and an enhanced mirror [Peeters et al., Phys. Plasmas 16, 042310 (2009)]. These inertial terms become important in case strong rotation, as is common spherical devices, for heavy impurity ions even at small velocities. this work, first gyrokinetic simulations including strongly plasma...
This paper outlines an approach towards improved rigour in tokamak turbulence transport model validation within integrated modelling. Gaussian process regression (GPR) techniques were applied for profile fitting during the preparation of modelling simulations allowing rigourous sensitivity tests prescribed initial and boundary conditions as both fit derivative uncertainties are provided. was demonstrated by a JETTO simulation JET ITER-like-wall H-mode baseline discharge #92436 with QuaLiKiz...
Relativistic electron (RE) beams at high current density (low safety factor, qa) yet very low free-electron accessed with D2 secondary injection in the DIII-D and JET tokamak are found to exhibit large-scale MHD instabilities that benignly terminate RE beam. In JET, this technique has enabled termination of MA-level currents without measurable first-wall heating. This scenario thus offers an unexpected alternate pathway achieve mitigation collisional dissipation. Benign is explained by two...
Abstract We present an overview of results from a series L–H transition experiments undertaken at JET since the installation ITER-like-wall (JET-ILW), with beryllium wall tiles and tungsten divertor. Tritium, helium deuterium plasmas have been investigated. Initial in tritium show ohmic transitions low density power threshold for ( P LH ) is lower than ones densities, while we still lack contrasted data to provide scaling high densities. In there notable shift which minimum <?CDATA...
Abstract A toroidal Alfvén eigenmode (TAE) has been observed to be driven by alpha particles in a JET deuterium-tritium internal transport barrier plasma. The observation occurred 50 ms after the removal of neutral beam heating (NBI). mode is on magnetics, soft-xray, interferometry and reflectometry measurements. We present detailed stability calculations using similar tool set validated during deuterium only discharges. These strongly support conclusion that TAE, this was destabilized...
Abstract The recent deuterium–tritium campaign in JET-ILW (DTE2) has provided a unique opportunity to study the isotope dependence of L-H power threshold an ITER-like wall environment (Be and W divertor). Here we present results from dedicated transition experiments at JET-ILW, documenting tritium plasmas, comparing them with matching deuterium hydrogen datasets. From earlier it is known that as plasma isotopic composition changes deuterium, through varying deuterium/hydrogen concentrations,...
Abstract The pre-thermal quench (pre-TQ) dynamics of a pure deuterium ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi mathvariant="normal">D</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:math> ) shattered pellet injection (SPI) into <mml:mn>3</mml:mn> <mml:mstyle scriptlevel="0"/> <mml:mi>MA</mml:mi> / <mml:mn>7</mml:mn> <mml:mi>MJ</mml:mi> JET H-mode plasma is studied via 3D non-linear MHD modelling with the JOREK code....
Abstract This paper presents a study on the dependence of ion temperature stiffness plasma main isotope mass in JET ITER-like wall and C discharges. To this aim, database H, D T shots is analyzed, including new dedicated shots, comparing experiments with lower higher power injected by NBI system. In order to characterize turbulence mass, three these discharges (two one D) same external heating scheme are studied detail interpreted gyrokinetic linear nonlinear simulations. The analysis...
Abstract A reduction of the pedestal pressure with increasing separatrix density over ( n e sep / ped ) has been observed in JET. The physics behind this correlation is investigated. due to two distinct mechanisms. increase till ≈0.4 shifts radially outwards, decreasing peeling-balloning stability and reducing height. effect position saturates above ≈ 0.4. For higher values, ascribed increased turbulent transport and, likely, resistive MHD effects. reduces ∇ /n , η transport. This gradient...
Abstract Runaway electrons (REs) created during tokamak disruptions pose a threat to the reliable operation of future larger machines. Experiments using shattered pellet injection (SPI) have been carried out at JET investigate ways prevent their generation or suppress them if avoidance is not sufficient. Avoidance possible SPI contains sufficiently low fraction high-Z material, it fired early in advance disruption prone runaway generation. These results are consistent with previous similar...
A finite radial temperature gradient has been observed to be maintained within magnetic islands in gyro-kinetic turbulence simulations despite the fast motion along field, and is related trapped particles which do not move field around island. Recent calculations of interaction drift-wave with have shown that can exist separatrix, turn allows only partial flattening electron profiles. Here we calculate, using a minimal drift-kinetic model, effect on bootstrap current tokamak. Consequences...
The first experimental evidence of parallel momentum transport generated by the up-down asymmetry a toroidal plasma is reported. experiments, conducted in Tokamak à Configuration Variable, were motivated recent theoretical discovery ion-scale turbulent induced an magnetic equilibrium. rotation gradient observed to depend on outer part leading variation central factor 1.5-2. direction effect and its magnitude are agreement with predictions for eight possible combinations asymmetry, current, field.