A5082164438- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Nuclear reactor physics and engineering
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Nuclear Materials and Properties
- Electrostatic Discharge in Electronics
- Laser-induced spectroscopy and plasma
- Nuclear Physics and Applications
- Diamond and Carbon-based Materials Research
- Radiative Heat Transfer Studies
- Atomic and Molecular Physics
- Silicon and Solar Cell Technologies
- High-Energy Particle Collisions Research
- Dust and Plasma Wave Phenomena
- Gas Dynamics and Kinetic Theory
- Vacuum and Plasma Arcs
- Computational Fluid Dynamics and Aerodynamics
- Advanced Control Systems Optimization
- Nuclear Engineering Thermal-Hydraulics
- Particle Accelerators and Free-Electron Lasers
Max Planck Institute for Plasma Physics
2015-2024
University of Rome Tor Vergata
2024
École Polytechnique Fédérale de Lausanne
2002-2023
Max Planck Institute for Plasma Physics - Greifswald
2023
Culham Science Centre
2010-2022
Culham Centre for Fusion Energy
2013-2022
Max Planck Society
2012-2021
Oak Ridge National Laboratory
2021
Royal Military Academy
2020
Max Planck Innovation
2005-2007
A future fusion reactor is expected to have all-metal plasma facing materials (PFMs) ensure low erosion rates, tritium retention and stability against high neutron fluences. As a consequence, intrinsic radiation losses in the edge divertor are comparison devices with carbon PFMs. To avoid localized overheating divertor, low-Z medium-Z impurities be inserted into convert major part of power flux facilitate partial detachment. For burning conditions ITER, which operates not far above L–H...
The physics base for the ITER Physics Design Guidelines is reviewed in view of application to DEMO and areas are pointed out which improvement needed arrive at a consistent set Guidelines. Amongst proposed improvements, area power exhaust plays crucial role since predictive capability present-day models low this expected play major limiting designs due much larger value Ptot/R than devices even ITER.
Detachment of high power discharges is obtained in ASDEX Upgrade by simultaneous feedback control core radiation and divertor or thermoelectric currents the injection radiating impurities. So far 2/3 ITER normalized heat flux Psep/R = 15 MW m−1 has been under partially detached conditions with a peak target well below 10 m−2. When detachment further pronounced towards lower at target, substantial changes edge localized mode (ELM) behaviour, density distribution occur. The time-averaged both...
The first stable completely detached H-mode plasma in the full tungsten ASDEX Upgrade has been achieved. Complete detachment of both targets is induced by nitrogen seeding into divertor. Two new phases are added to classification described Potzel et al (2014 Nucl. Fusion 54 013001): first, line integrated density increases about 15% with partial outer Second, complete correlated appearance intense, strongly localized, radiation at X-point. Radiated power fractions, frad, increase from 50%...
In this paper, a new experimental classification of divertor detachment in ASDEX Upgrade is presented. For purpose, series ohmic and L-mode density ramp discharges at different heating powers, magnetic field directions plasma species were carried out. the first time electron volume occurrence recombination measured by means spectroscopy. It shown that not continuously evolving process but rather undergoes three distinct states while characteristics inner outer are strongly coupled. Before...
In the European fusion roadmap, ITER is followed by a demonstration power reactor (DEMO), for which conceptual design under development. This paper reports first results of coherent effort to develop relevant physics knowledge that (DEMO Physics Basis), carried out experts. The program currently includes investigations in areas scenario modeling, transport, MHD, heating & current drive, fast particles, plasma wall interaction and disruptions.
Operation of DEMO in comparison to ITER will be significantly more demanding, as various additional limitations physical and technical nature have respected. In particular a set extremely restrictive boundary conditions on divertor operation during between ELMs It is high importance describe these order consider them early possible the ongoing development concept design. This paper extrapolates existing physics basis power particle exhaust DEMO.
A multidiagnostic approach, utilizing Langmuir probes in the midplane, X-point and divertor walls, along with lithium beam infrared measurements is employed to evaluate evolution of scrape-off layer (SOL) ASDEX Upgrade across L-mode density transition leading formation a shoulder. The flattening SOL profiles linked regime change filaments, which become faster larger, similar q∥ profile. This related beginning outer detachment leads onset velocity shear SOL. Experimental are good agreement...
Future fusion reactors require a safe, steady state divertor operation. A possible solution for the power exhaust challenge is detached operation in scenarios with high radiated fractions. The radiation can be increased by seeding impurities, such as N dominant scrape-off-layer radiation, Ne or Ar SOL and pedestal Kr core radiation. Recent experiments on two of all-metal tokamaks, ASDEX Upgrade (AUG) JET, demonstrate fractions fully-detached N, conventional vertical target geometry. For both...
Experimental evidence for the impact of a region high density localised in high-field side scrape-off layer (the HFSHD) on plasma confinement is shown various dedicated experiments ASDEX Upgrade (AUG). Increasing main ion fuelling to increase separatrix and shift profile outwards. Predictive pedestal modelling this indicates 25% decrease attainable top pressure, which compares well with experimental observations gas scan.
Abstract Future fusion reactors require a safe, steady state divertor operation. The required detached operation is, in tokamaks with metal walls, usually achieved by seeding of impurities, such as nitrogen. With strong levels, the dominant radiation is emitted from small, poloidally localized volume inside confined region, vicinity X-point. location radiating observed to vary relative X-point depending on and power i.e. degree detachment. At ASDEX Upgrade tokamak, position radiator can be...
The understanding of divertor physics and the evolution detachment is crucial for developing capability to model power exhaust in current experiments reliably predict it future fusion devices. In simulations ASDEX Upgrade, an experimentally observed region high density field side scrape-off layer has been recovered. Validated modeling with SOLPS5.0 shows that a detailed match plasma not only important local parameters, but can lead strong changes global parameters. Drifts play role...
Abstract Based on particle and energy balances, a reduced model is derived for the physical mechanisms leading to occurrence of stable unstable X-point radiators (XPRs), latter also known as marfes. The roles neutral deuterium density in divertor region initiating XPRs highlighted. An access condition formulated whose parameter dependencies are consistent with experimental observations which could apply process detachment. With an exponential increase recombination rate at low temperature,...
A summary of recent results on filamentary transport, mostly obtained with the ASDEX-Upgrade tokamak (AUG), is presented and discussed in an attempt to produce a coherent picture scrape-off layer (SOL) transport. clear correlation found between L-mode density shoulder formation outer midplane transition sheath-limited inertial regimes. Divertor collisionality be parameter triggering transition. reduction ion temperature takes place far SOL after transition, both for background filaments....
A simple analytical formula for the impurity seeded partially detached divertor operational point has been developed using 1D modelling. The inclusion of charge exchange momentum loss terms improves modelling ASDEX Upgrade conditions and its extrapolation to larger devices. investigations are concentrated around a working low heat flux an electron temperature 2.5 eV at target which required maintain sputtering rates tungsten plate. An experimental onset detachment by nitrogen seeding in is...
Future fusion reactors require a safe, steady-state divertor operation. With deep detachment, which is typically induced by impurity seeding, the radiation concentrates in small region at X-point or on closed flux surfaces above X-point. This so-called radiator (XPR) moves further inside confined with increasing seeding and location can be actively controlled. At AUG, parameter space for operation an XPR was significantly extended, using active feedback location. The observed nearly whole...
To study the impact of strong impurity radiation on energy confinement and discharge stability at JET-ILW, dedicated high-density, highly heated experiments with neon seeding have been performed. In these an increase in core especially pedestal region plus a characteristic X-point radiator inside confined observed. The increased separatrix had no confinement. Only highest puff rates heating powers () weak H-mode without back-transitions to L-mode (M-mode) could be achieved, while lower or...
In this work we carry out quantitative measurements of particle and heat transport associated to SOL filaments in a tokamak, relate density shoulder formation the advection energy far SOL. For first time, attempt includes direct ion electron temperatures for background filaments. With aim, combine data from number equivalent L-mode discharges ASDEX Upgrade tokamak which different probe heads were installed on midplane manipulator. This approach is validated by comparison with independent...
The effect of the upcoming TCV divertor upgrade on distribution neutrals and onset detachment is studied using 2D transport code simulations. centered around installation a gas baffle to form chamber variable closure. SOLPS-ITER simulations predict that geometry selected be installed in 2019 increases neutral density by factor ∼5 compression one order magnitude typical single null, Ohmic heated scenarios (330 kW). further with addition auxiliary heating systems (1.2 MW). Simulations show...
Abstract The X-point radiator (XPR) is an attractive scenario that may contribute to solving the power exhaust problem in future fusion devices. 2D transport code SOLPS-ITER was applied reproduce experimentally measured plasma condition with XPR ASDEX Upgrade tokamak and compare a reduced model. Neutrals penetrating from adjoining cold divertor region large connection length near play important role initiating XPR. However, once such created, it persists even if fueling impurity seeding...