A5052239618- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Laser-Plasma Interactions and Diagnostics
- Nuclear Materials and Properties
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Nuclear Physics and Applications
- Spacecraft and Cryogenic Technologies
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Calibration and Measurement Techniques
- Particle Accelerators and Free-Electron Lasers
- High-pressure geophysics and materials
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear Engineering Thermal-Hydraulics
- Vacuum and Plasma Arcs
- Atomic and Molecular Physics
- Metallurgical Processes and Thermodynamics
- Diamond and Carbon-based Materials Research
- Silicon Carbide Semiconductor Technologies
- Cyclone Separators and Fluid Dynamics
Max Planck Institute for Plasma Physics
2016-2025
Universitätsklinikum Tübingen
2025
Max Planck Society
2012-2021
Institute for Particle and Nuclear Physics
2016
HUN-REN Wigner Research Centre for Physics
2016
Dutch Institute for Fundamental Energy Research
2014
University of California, San Diego
2014
Technical University of Munich
2014
University of Fribourg
2014
Max Planck Institute for Plasma Physics - Greifswald
2011
Progress, since the ITER Physics Basis publication (ITER Editors et al 1999 Nucl. Fusion 39 2137–2664), in understanding processes that will determine properties of plasma edge and its interaction with material elements is described. Experimental areas where significant progress has taken place are energy transport scrape-off layer (SOL) particular anomalous scaling, particle SOL plays a major role diverted plasmas main-chamber elements, localized mode (ELM) deposition on mechanism for ELM...
A multi-machine database for the H-mode scrape-off layer power fall-off length, λq in JET, DIII-D, ASDEX Upgrade, C-Mod, NSTX and MAST has been assembled under auspices of International Tokamak Physics Activity. Regression inside finds that most important scaling parameter is poloidal magnetic field (or equivalently plasma current), with decreasing linearly increasing Bpol. For conventional aspect ratio tokamaks, regression , yielding λq,ITER ≅ 1 mm baseline inductive burning scenario at Ip...
Analysis of Type I ELMs from ongoing experiments shows that ELM energy losses are correlated with the density and temperature pedestal plasma before crash. The loss normalized to is found correlate across collisionality (ν*ped), decreasing increasing ν*ped. Other parameters affect size, such as edge magnetic shear, etc, which influence volume affected by ELMs. particle influenced this weakly dependent on other parameters. In JET DIII-D, under some conditions, can be observed (`minimum'...
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,...
Experimental measurements of the SOL power decay length (λ(q)) estimated from analysis fully attached divertor heat load profiles two tokamaks, JET and ASDEX Upgrade, are presented. Data was measured by means infrared thermography. An empirical scaling reveals parametric dependency λ(q) in mm = 0.73B(T)(-0.78)q(cyl)(1.2)P(SOL)(0.1)R(geo)(0), where B(T)(T) describes toroidal magnetic field, q(cyl) cylindrical safety factor, P(SOL)(MW) crossing separatrix R(geo)(m) major radius device. A...
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...
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...
A new thermography system with high time resolution was put into operation at ASDEX-Upgrade and is routinely used to determine the energy flux onto lower diverter plates. The measurements allow power deposition be characterized during dynamic events such as ELMs disruptions, well asymmetry of inboard/outboard load. balance set up even single discharges losses are found fairly equal input.
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...
Recent research in scrape-off layer (SOL) and divertor physics is reviewed; new existing data from a variety of experiments have been used to make cross-experiment comparisons with implications for further ITER. Studies the region near separatrix addressed relationship profiles turbulence as well scaling parallel power flow. Enhanced low-field side radial transport implicated driving flows inboard side. The medium-n nature edge localized modes (ELMs) has elucidated measurements determined...
A newly established scaling of the ELM energy fluence using dedicated data sets from JET operation with CFC & ILW plasma facing components (PFCs), ASDEX Upgrade (AUG) both and full-W PFCs MAST walls has been generated. The reveals an approximately linear dependence peak pedestal top electron pressure minor radius; a square root is seen on relative loss energy. result this gives range in parallel 10–30 MJm−2 for ITER Q= 10 2.5–7.5 intermediate at 7.5 MA 2.65 T. These latter numbers are...
Abstract A double radiative feedback technique has been developed on the ASDEX Upgrade tokamak for optimization of power exhaust with a standard vertical target divertor. The main chamber radiation is measured in real time by subset three foil bolometer channels and controlled argon injection outer midplane. heat flux addition nitrogen divertor private region using either thermoelectric sensor or scaled obtained channel No negative interference two controllers observed so far. combination...
H modes with good confinement and small ELMs the characteristics of type II or grassy have been observed on ASDEX Upgrade. Such an ELM behaviour is essential to minimize erosion divertor tiles in any next step device. For first time, operation this favourable could be demonstrated close Greenwald density. Even for such high densities, energy times were recent mode scalings. High density even seems favourable, since steady state pure ELMy phases Upgrade are obtained only above e/GW ⩾ 0.85....
In the ASDEX Upgrade tokamak, complex power deposition structures on divertor target plates during type-I edge-localized modes (ELMs) have been discovered by fast (few microseconds), two-dimensional (40 x 40 cm(2)) infrared thermography. addition to usual axisymmetric line near separatrix, there appear, statistically distributed, several laterally displaced and inclined stripes, mostly well separated from each other main strike zone. These are interpreted as footprints of approximately field...
Recent experiments on the Type I ELMy H-mode regime performed at JET with improved diagnostics have expanded range of parameters for study ELM energy and particle losses. Deviations from standard behaviour such losses in some areas operating space revealed that are correlated (density temperature) pedestal plasma before crash, while other global characteristics (such as frequency) a consequence ELM-driven flux in-between confinement. The relative loss (to energy) is found to correlate well...
Feedback-controlled puffing of neon and deuterium has been applied to control the edge-localized-mode behavior target plate power deposition during high-power $H$-mode discharges in ASDEX Upgrade. A regime found which more than 90% heating is lost through radiation divertor detachment occurs, without deterioration energy confinement. The plasma remains $H$ mode, exhibiting small-amplitude, high-frequency ELM's, do not penetrate plates strike zone region.
Edge-localized modes (ELMs) are repetitive instabilities that occur in the outer region of tokamak plasmas. This Letter provides new information on and implications evolution filament structures observed during ELMs MAST tokamak. The filaments exist for time over which particles being released into scrape off layer. They start at plasma edge rotating velocity pedestal, then decelerate toroidally accelerate radially outwards. As propagate they remain aligned with local magnetic field line.
The boundary of the tokamak core plasma, or scrape-off layer, is normally characterized in terms average parameters such as density, temperature and e-folding lengths suggesting diffusive losses. However, shown this paper, localized filamentary structures play an important role determining radial efflux both L mode during edge modes (ELMs) on MAST. Understanding size, poloidal toroidal localization outward extent these filaments crucial order to calculate their effect power loading first...
New experimental results on transient loads during ELMs and disruptions in present divertor tokamaks are described used to carry out a extrapolation ITER reference conditions draw consequences for its operation. In particular, the achievement of low energy/convective type I edge localized modes (ELMs) ITER-like plasma seems only way obtain which may be compatible with an acceptable erosion lifetime facing components (PFCs) ITER. Power disruptions, contrary, seem lead most cases because...
In the ASDEX Upgrade tokamak, power deposition structures on divertor target plates during type-I edge localized modes (ELMs) have been investigated by infrared thermography. addition to axisymmetric strike line, several poloidally displaced stripes are resolved, identifying an ELM as a composite of subevents. This pattern is interpreted being signature helical perturbations in low field side non-linear evolution. Based this observation, related magnetic perturbation midplane can be derived...
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...