A5008442059- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Fusion materials and technologies
- Laser-Plasma Interactions and Diagnostics
- Electrostatic Discharge in Electronics
- Nuclear Physics and Applications
- Laser-induced spectroscopy and plasma
- Tropical and Extratropical Cyclones Research
- GNSS positioning and interference
- High voltage insulation and dielectric phenomena
- Particle Accelerators and Free-Electron Lasers
- Magneto-Optical Properties and Applications
- Electromagnetic Scattering and Analysis
- Advanced Frequency and Time Standards
- Antenna Design and Analysis
- Quantum optics and atomic interactions
- Electron and X-Ray Spectroscopy Techniques
- Geophysical Methods and Applications
- Stability and Control of Uncertain Systems
- Microwave and Dielectric Measurement Techniques
- Lightning and Electromagnetic Phenomena
Max Planck Institute for Plasma Physics
2016-2025
Max Planck Society
2012-2021
Institute of Plasma Physics and Laser Microfusion
2021
Max Planck Innovation
2002-2017
Centre National de la Recherche Scientifique
2015
Université de Lorraine
2015
Institut Jean Lamour
2015
Ghent University
2015
Royal Military Academy
2011
Eurogentec (Belgium)
2009
Abstract The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and preparation operation, as well addressing issues for a future DEMO design. Since 2015, AUG equipped with new pair 3-strap ICRF antennas, which were designed reduction tungsten release during operation. As predicted, factor two on ICRF-induced W plasma content could be achieved by sheath voltage at antenna limiters via compensation image currents central side straps in...
The European DEMO is a pulsed device with pulse length of 2 hours. functions devoted to the heating and current drive system are: plasma breakdown, ramp-up flat-top where fusion reactions occur, control during phase, finally ramp-down. EU-DEMO project was in Pre-Concept Design Phase 2014-2020, meaning that some cases, design values precise requirements from physics point view were not yet frozen. A total 130 MW considered for all phases plasma: flat top, 30 required neoclassical tearing...
A comparison of the ASDEX Upgrade 3-strap ICRF antenna data with linear electromagnetic TOPICA calculations is presented.The substantiates a reduction local electric field at radially protruding plasma-facing elements as relevant approach for minimizing tungsten (W) sputtering in conditions when slow wave strongly evanescent.The measured reaction time-averaged RF current limiters to feeding variations less sensitive than predicted by calculations.This likely have been caused temporal and...
Recent experiments at ASDEX Upgrade have achieved advanced scenarios with high βN (>3) and confinement enhancement over ITER98(y, 2) scaling, HH98y2 = 1.1–1.5, in steady state. These discharges been obtained a modified divertor configuration for Upgrade, allowing operation higher triangularity, changed neutral beam injection (NBI) system, more tangential, off-axis deposition. The figure of merit, βNHITER89-P, reaches up to 7.5 several seconds plasmas approaching stationary conditions....
Experiments with boron-coated side limiters of two antennas operated together in 2012 showed that the are responsible for more than half increased W content plasma. Together contribution from other limiter tiles, not replaced 2012, account at least thirds content. A modified test two-strap ion cyclotron range frequency (ICRF) ASDEX Upgrade broad and narrow straps has shown an improved operation full wall 2011/2012 campaigns up to a 40% lower rise concentration allowing stable low deuterium...
Abstract The 3-strap antennas in ASDEX Upgrade allow ICRF operation with low tungsten (W) content the confined plasma W-coated antenna limiters. With configuration, local W impurity source at is drastically reduced and core concentration similar to that of boron coated 2-strap a given power. Operation power ratio between central outer straps <?CDATA $1.5:1$ ?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mstyle displaystyle="false"> <mml:mn>1.5</mml:mn>...
Abstract Experiments on ASDEX Upgrade (AUG) in 2021 and 2022 have addressed a number of critical issues for ITER EU DEMO. A major objective the AUG programme is to shed light underlying physics confinement, stability, plasma exhaust order allow reliable extrapolation results obtained present day machines these reactor-grade devices. Concerning pedestal physics, mitigation edge localised modes (ELMs) using resonant magnetic perturbations (RMPs) was found be consistent with reduction linear...
Recent achievements in studies of the effects ICRF (Ion Cyclotron Range Frequencies) power on SOL (Scrape-Off Layer) and PWI (Plasma Wall Interactions) ASDEX Upgrade (AUG), Alcator C-Mod, JET-ILW are reviewed. Capabilities to diagnose model effect DC biasing associated impurity production at active antennas magnetic field connections described. The experiments show that near-fields can lead not only E × B convection, but also modifications density, which for C-Mod limited a narrow region...
Abstract The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance physics base of ITER and DEMO. Here, full tungsten wall is a key asset for extrapolating future devices. high overall heating power, flexible mix comprehensive diagnostic set allows studies ranging from mimicking scrape-off-layer divertor conditions DEMO at density fully non-inductive operation ( q 95 = 5.5, ) low density. Higher installed electron cyclotron...
The B-dot probe diagnostic suite on the ASDEX Upgrade tokamak has recently been upgraded with a new 125 MHz, 14 bit resolution digitizer to study ion cyclotron emission (ICE). While classic edge from low field side plasma is often observed, we also measure waves originating core fast fusion protons or beam injected deuterons being possible driver. Comparing measured frequency values harmonics present in places origin of this magnetic axis, fundamental hydrogen/second deuterium harmonic...
Abstract Experiments have been performed under the coordination of International Tokamak Physics Activity (ITPA) on several tokamaks, including ASDEX Upgrade (AUG), JET and DIII-D, to characterize increased Ion cyclotron range frequency (ICRF) antenna loading achieved by optimizing position gas injection relative RF antennas. On AUG (with ITER-Like Wall) a 50% increase in was observed when injecting deuterium ELMy H-mode plasmas using mid-plane inlets close powered antennas instead divertor...
Abstract An overview of recent results obtained at the tokamak ASDEX Upgrade (AUG) is given. A work flow for predictive profile modelling AUG discharges was established which able to reproduce experimental H-mode plasma profiles based on engineering parameters only. In center, theoretical predictions current redistribution by a dynamo effect were confirmed experimentally. For core transport, stabilizing fast ion distributions turbulent transport shown be important explain isotope and...
In ASDEX Upgrade H-modes with H98≈0.95, similar effect of the ICRF antenna loading improvement by local gas injection was observed as previously in L-modes. The resistance Ra between and during ELMs can increase more than 25% after a switch-over from deuterium rate 7.5⋅1021 D/s injected toroidally remote location to same amount close an antenna. However, contrast L-mode, this is small H-mode when valve downstream w.r.t. parallel plasma flows used. non-linearity at PICRP<30 kW using...
Core ion cyclotron emission (ICE) signals have recently been observed in beam-heated plasmas on several tokamaks. In this manuscript we present experimental evidence support of core ICE being generated by the magnetoacoustic instability (MCI), itself driven velocity-space inversion sub-Alfvénic beam-injected ions. The amplitude evolution is consistent with MCI and a result competition between beam fraction build-up (which increases growth rate) slowing down dominant velocity component...
A new B-dot probe-based diagnostic has been installed on an ASDEX Upgrade tokamak to characterize ion cyclotron range-of frequency (ICRF) wave generation and interaction with magnetized plasma. The consists of a field-aligned array probes, oriented measure fast slow ICRF fields their wavenumber (k(//)) spectrum the low field side Upgrade. thorough description supporting electronics is provided. In order compare measured dominant local expected launched waves, in-air near-field measurements...
Abstract Bursts of ion cyclotron emission (ICE), with spectral peaks corresponding to the hydrogen harmonic frequencies in plasma core are detected from helium plasmas heated by sub-Alfvénic beam-injected ions ASDEX Upgrade tokamak. Based on fast distribution function obtained TRANSP/NUBEAM code, together a linear analytical theory magnetoacoustic instability (MCI), growth rates MCI could be calculated. In our theoretical and experimental studies, we found that excitation mechanism ICE...
Ion and electron temperature profiles in conventional L H mode on ASDEX Upgrade are generally stiff limited by a critical gradient length ∇T/T as given ion (ITG) driven turbulence. ECRH experiments indicate that (Te) also stiff, predicted turbulence with streamers. Accordingly, the core edge temperatures proportional to each other plasma energy is pedestal pressure for fixed density profiles. Density not confinement improves peaking. Medium triangularity shapes (δ<0.45) show strongly...
Abstract The paper presents the first reported observation of high frequency Alfvén eigenmode excitation on ASDEX Upgrade tokamak. mode is driven in a novel way using radio (RF) wave acceleration either beam-injected deuterium ions or thermal He-3 minority three-ion heating scenario. In case beam ion acceleration, instability only appears during deuteron at third cyclotron harmonic (wave ω = 3Ω D where Ω frequency), as not detected more commonly used second harmonic/minority scenario absence...
A new multichannel frequency modulated continuous-wave reflectometry diagnostic has been successfully installed and commissioned on ASDEX Upgrade to measure the plasma edge electron density profile evolution in front of Ion Cyclotron Range Frequencies (ICRF) antenna. The design three-strap ICRF antenna integrates ten pairs (sending receiving) microwave antennas. reflectometer can use three these profiles up 2 × 1019 m−3, at different poloidal locations, allowing direct study local layers...
Ion cyclotron emission (ICE) signals whose spectral peaks match the fundamental frequencies of hydrogen and tritium in plasma core, near magnetic axis, are observed ASDEX Upgrade deuterium plasmas.In these cases only source energetic (1 MeV) ions is D-D fusion reactions between neutral beam injected bulk ions.Hydrogen-matched core ICE a wide variety plasmas, while tritium-matched (so far) socalled H-mode density limit all detected directly using B-dot probes, which provide information on...
Use of new 3-strap ICRF antennas with all-tungsten (W) limiters in ASDEX Upgrade results a reduction the W sources at antenna and content confined plasma by least factor 2 compared to W-limiter 2-strap used past. The is observed broad range shapes. In multiple locations frame, limiter source has minimum when RF image currents are decreased cancellation current contributions central outer straps. JET ITER-like wall, produces about 20% less main chamber radiation old A2 antennas. However...