A5029149326- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Solar and Space Plasma Dynamics
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Nuclear Materials and Properties
- Plasma Diagnostics and Applications
- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- Nuclear Physics and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Metallurgical Processes and Thermodynamics
- Atomic and Subatomic Physics Research
- High-Energy Particle Collisions Research
- High-pressure geophysics and materials
- Graphite, nuclear technology, radiation studies
- GNSS positioning and interference
- Spacecraft and Cryogenic Technologies
- Particle Accelerators and Free-Electron Lasers
- Cold Fusion and Nuclear Reactions
- Geophysics and Gravity Measurements
- Advanced Algorithms and Applications
Max Planck Institute for Plasma Physics
2016-2025
Institut de Recherche sur la Fusion par Confinement Magnétique
2024
CEA Cadarache
2024
Fusion Academy
2015-2023
Fusion (United States)
2015-2023
University of Milano-Bicocca
2022
Culham Science Centre
2014-2022
Max Planck Society
2012-2021
National Centre for Nuclear Research
2021
Ludwig-Maximilians-Universität München
2020
First experiments with nonaxisymmetric magnetic perturbations, toroidal mode number $n=2$, produced by newly installed in-vessel saddle coils in the ASDEX Upgrade tokamak show significant reduction of plasma energy loss and peak divertor power load associated type-I edge localized modes (ELMs) high-confinement plasmas. ELM mitigation is observed above an density threshold obtained both perturbations that are resonant not safety factor profile. Compared unperturbed ELMy reference plasmas,...
Tungsten (W) has moved into the focus of fusion research being a main candidate for plasma facing components (PFCs) ITER and future reactor. A ingredient understanding influence W as impurity its impact on is spatially resolved spectroscopic diagnosis W. The experimental investigations at ASDEX Upgrade most intense emissions ions (about I-like W21+ to Mn-like W49+) in VUV soft x-ray region covering electron temperature range from about 0.5–5.0 keV. relative shape fractional abundances...
The tungsten programme in ASDEX Upgrade is pursued towards a full high-Z device. spectroscopic diagnostic of W has been extended and refined the cooling factor re-evaluated. coated surfaces now represent fraction 65% all plasma facing components (24.8 m2). only two major that are not yet strikepoint region lower divertor as well limiters at low field side. While extending surfaces, concentration discharge behaviour have changed gradually pointing to critical issues when operating with wall:...
The cooling factor of W is evaluated using state the art data for line radiation and an ionization balance which has been benchmarked with experiment. For calculation radiation, level-resolved calculations were performed Cowan code to obtain electronic structure excitation cross sections (plane-wave Born approximation). processed by a collisional radiative model electron density dependent emissions. These then combined power derived from recombination rates bremsstrahlung total factor....
Feedback control of the divertor power load by means nitrogen seeding has been developed into a routine operational tool in all-tungsten clad ASDEX Upgrade tokamak. For heating powers above about 12 MW, its use become inevitable to protect tungsten coating under boronized conditions. The is accompanied improved energy confinement due higher core plasma temperatures, which more than compensates negative effect dilution on neutron rate. This paper describes technical details feedback...
The behaviour of tungsten in the core hybrid scenario plasmas JET with ITER-like wall is analysed and modelled a combination neoclassical gyrokinetic codes. In these discharges, good confinement conditions can be maintained only for first 2?3?s high power phase. Later W accumulation regularly observed, often accompanied by onset magneto-hydrodynamical activity, particular tearing modes (NTMs), both which have detrimental effects on global energy confinement. dynamics process examined, taking...
The installation of a new poloidal charge exchange recombination spectroscopy (CXRS) diagnostic at ASDEX Upgrade (AUG) has enabled the determination radial electric field, Er, using force balance impurity ions. Er been derived from (CX) spectra measured on different species, such as He2+, B5+, C6+ and Ne10+. resulting profiles are found to be identical within uncertainties regardless species used, thus, demonstrating validity technique. profile compared main ion pressure gradient term, which...
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.
The charge exchange recombination spectroscopy (CXRS) diagnostics at ASDEX Upgrade (AUG) have been upgraded and extended to provide high-resolution measurements of impurity ion temperature, density, rotation profiles. existing core toroidal CXRS diagnostic has refurbished increase the level signal, thus enabling shorter exposure times down 3.5 ms. Additional lines sight more detailed profiles enable simultaneous multiple impurities. In addition, a new system installed, which allows for...
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...
Abstract A large scale program to develop a conceptual design for demonstration fusion power plant (DEMO) has been initiated in Europe. Central elements are the baseline points, which developed by system codes. The assessment of credibility these points is often hampered missing information. main physics and technology content central European codes have published (Kovari et al 2014 Fusion Eng. Des . 89 3054–69, 2016 104 9–20, Reux 2015 Nucl. 55 073011). In addition, this publication...
In the present work, tolerable impurity level and composition for a reactor plasma using several sets of model assumptions are evaluated. Special care was taken to evaluate comprehensive consistent set atomic data 35 different elements, such that various elements may be studied as function their nuclear charge. The not only useful presented work or system codes which design fusion reactors, but also interpretation bolometric measurements. Additionally, predictions spectral distribution...
Abstract An overview of results negative triangularity (NT) studies from the ASDEX Upgrade tokamak (AUG) is given. Moderate values in range δ average ≈ −0.2 have been obtained. Results both unfavorable and favorable magnetic configuration terms high-confinement mode (H-mode) access are presented. In configuration, ion grad B drift points away active x-point, which usually a factor 2 higher power thresholds to enter H-mode. low-confinement (L-mode) operation confirmed at high auxiliary...
ASDEX Upgrade has recently finished its transition towards an all-W divertor tokamak, by the exchange of last remaining graphite tiles to W-coated ones. The plasma start-up was performed without prior boronization. It found that large He content in plasma, resulting from DC glow discharges for conditioning, leads a confinement reduction. After change D inter-shot quickly dropped and, parallel, usual H-Mode with H factors close one achieved. initial conditioning phase, oxygen concentrations...
After completion of the tungsten coating all plasma facing components, ASDEX Upgrade has been operated without boronization for 1 1/2 experimental campaigns. This allowed study fuel retention under conditions relatively low D co-deposition with low- Z impurities as well operational space a full-tungsten device unfavourable condition high intrinsic impurity level. Restrictions in operation were caused by central accumulation combination density peaking, resulting H–L backtransitions induced...
Observations in the ASDEX Upgrade tokamak show a correlation between gradient of intrinsic toroidal rotation profile and logarithmic electron density profile. The center plasma reverses from co- to countercurrent when gradients are large, turbulence is either dominated by trapped modes or at transition ion temperature modes. A study based on local gyrokinetic calculations suggests that dominant trend observations can be explained combination residual stresses produced E × B shearing mechanisms.
In 2008, experiments have been carried out in ASDEX Upgrade to compare Hmode power threshold and confinement time helium deuterium.A scan magnetic field a wide density variation indicate that the two gases is very similar.The dependence of exhibits clear minimum.Confinement about 30% lower than deuterium, mainly due reduction ion caused by Z=2 helium.
The W-transport in the core plasma of JET is investigated experimentally by deriving W-concentration profiles from modelling signals soft x-ray cameras. For case pure neutral beam heating W accumulates (r/a < 0.3) approaching W-concentrations 10−3 between sawtooth crashes, which flatten W-profile to a concentration about 3 × 10−5. When central Ion cyclotron resonant additionally applied decays phases that exhibit changed mode activity, while also electron temperature increases and density...
In ASDEX Upgrade the compatibility of improved H-modes with an all-W wall has been demonstrated. Under boronized conditions light impurities and radiated power fraction in divertor were reduced, requiring N seeding to cool plasma. The impurity does not only protect tiles but also considerably improves performance H-mode discharges by up 25%. energy confinement increases H 98 -factors 1.3 thereby exceeds best values carbon-dominated AUG at same density collisionality. This improvement is due...
Recent developments in theory-based modelling of core heavy impurity transport are presented, and shown to be necessary for quantitative description present experiments JET ASDEX Upgrade. The treatment impurities is complicated by their large mass charge, which result a strong response plasma rotation or any small background electrostatic field the plasma, such as that generated anisotropic external heating. These forces lead poloidal asymmetries density, have recently been added numerical...
The results from ASDEX Upgrade discharges dedicated specifically to the investigation of low-density L-to-H transitions are presented. plasmas were heated by electron cyclotron resonance heating achieve a separation and ion heat channels. Under such conditions, ratio temperature at plasma edge increases with decreasing density L–H transition can be as high 3.5. Our strongly support essential role channel in transition, via diamagnetic E r provided pressure gradient.