P. Drewelow
A5089505133- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Nuclear reactor physics and engineering
- Laser-Plasma Interactions and Diagnostics
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Nuclear Physics and Applications
- Nuclear Engineering Thermal-Hydraulics
- High-Energy Particle Collisions Research
- Geophysics and Gravity Measurements
- Laser-induced spectroscopy and plasma
- Atomic and Molecular Physics
- Nuclear Materials and Properties
- Meteorological Phenomena and Simulations
- Astronomical Observations and Instrumentation
- Geomagnetism and Paleomagnetism Studies
- Electromagnetic Launch and Propulsion Technology
- Calibration and Measurement Techniques
- Fluid Dynamics and Turbulent Flows
- Infrared Target Detection Methodologies
- Optical Systems and Laser Technology
- Particle Accelerators and Free-Electron Lasers
Max Planck Institute for Plasma Physics - Greifswald
2015-2024
Max Planck Society
2012-2021
Max Planck Institute for Plasma Physics
2012-2021
Princeton Plasma Physics Laboratory
2021
HUN-REN Centre for Energy Research
2021
Royal Military Academy
2020
Culham Science Centre
2015-2016
Abstract The optimized superconducting stellarator device Wendelstein 7-X (with major radius , minor and plasma volume) restarted operation after the assembly of a graphite heat shield 10 inertially cooled island divertor modules. This paper reports on results from first high-performance operation. Glow discharge conditioning ECRH discharges in helium turned out to be important for density edge radiation control. Plasma densities with central electron temperatures were routinely achieved...
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...
Abstract Fusion energy research has in the past 40 years focused primarily on tokamak concept, but recent advances plasma theory and computational power have led to renewed interest stellarators. The largest most sophisticated stellarator world, Wendelstein 7-X (W7-X), just started operation, with aim show that earlier weaknesses of this concept been addressed successfully, intrinsic advantages persist, also at parameters approaching those a future fusion plant. Here we first physics...
Wendelstein 7-X is the first comprehensively optimized stellarator aiming at good confinement with plasma parameters relevant to a future power plant. Plasma operation started in 2015 using limiter configuration. After installing an uncooled magnetic island divertor, extending energy limit from 4 80 MJ, continued 2017. For this phase, electron cyclotron resonance heating (ECRH) capability was extended 7 MW, and hydrogen pellet injection implemented. The enhancements resulted highest triple...
The replacement of the JET carbon wall (C-wall) by a Be/W ITER-like (ILW) has affected plasma energy confinement. To investigate this, experiments have been performed with both C-wall and ILW to vary heating power over wide range for plasmas different shapes.
Disruptions are a major operational concern for next generation tokamaks, including ITER.They may generate excessive heat loads on plasma facing components, large electromagnetic forces in the machine structures and several MA of multi-MeV runaway electrons.A more complete understanding processes methods to suppress them is necessary ensure safe reliable operation future tokamaks.Runaway electrons were studied at JET-ILW showing that their dependencies (accelerating electric field, avalanche...
This paper reports the progress made at JET-ILW on integrating requirements of reference ITER baseline scenario with normalized confinement factor 1, a pressure 1.8 together partially detached divertor whilst maintaining these conditions over many energy times. The 2.5 MA high triangularity ELMy H-modes are studied two different configurations D-gas injection and nitrogen seeding. power load reduction N seeding is reported. relationship between an increase in pedestal investigated....
Wendelstein 7-X aims at quasi-steady state operation with up to 10 MW of heating power for 30 min. Power exhaust will be handled predominantly via actively water cooled CFC (carbon-fiber-reinforced carbon) based divertor units designed withstand loads MW/m2 locally in steady state. If local exceed this value, a risk delamination the and failure entire modules arises. Infrared endoscopes monitor all main plasma facing components are being prepared, near real time software tools under...
Abstract The fundamental behavior of the W7-X island divertor under detached conditions, which has been theoretically predicted with EMC3-Eirene code, is re-examined here experimental conditions achieved so far and compared first results. Both simulations experiments cover a range configurations plasma parameters, show following common trends: (1) rising impurity radiation, target heat load decreases ‘uniformly’ over entire surface in sense that both peak average loads can drop by an order...
Abstract Wendelstein 7-X (W7-X), the largest advanced stellarator, is built to demonstrate high power, performance quasi-continuous operation. Therefore, in recent campaign, experiments were performed prepare for long pulse operation, addressing three critical issues: development of stable detachment, control heat and particle exhaust, impact leading edges on plasma performance. The exhaust W7-X realized with help an island divertor, which utilizes large magnetic islands at boundary. This...
For stellarators, which need no or only small amounts of current drive, electron-cyclotron-resonance heating (ECRH) is a promising method even for the envisaged application in fusion power plant. Wendelstein 7-X (W7-X) equipped with steady-state capable ECRH system, operating at 140 GHz, corresponds to 2nd cyclotron harmonic electrons magnetic field 2.5 T. Ten gyrotrons are operational and already delivered 7 MW W7-X plasmas. Combined pellet injection, highest triple product (0.68 × 1020 keV...
The Wendelstein 7-X (W7-X) optimized stellarator fusion experiment, which went into operation in 2015, has been operating since 2017 with an un-cooled modular graphite divertor. This allowed first divertor physics studies to be performed at pulse energies up 80 MJ, as opposed 4 MJ the phase, where five inboard limiters were installed instead of a This, and number other upgrades device capabilities, extension regimes higher plasma density, heating power, performance overall, e.g. setting new...
Abstract Classical particle drifts are known to have substantial impacts on fluxes of particles and heat through the edge plasmas in both tokamaks stellarators. Here we present results from first dedicated investigation drift effects W7-X stellarator. By comparing similar plasma discharges conducted with a forward- reverse-directed magnetic field, could be isolated observation up-down asymmetries flux profiles divertor targets. In low-density plasmas, radial locations strike lines (i.e....
Pulsed injections of boron carbide granules into Wendelstein 7-X stellarator (W7-X) plasmas transiently increase the plasma stored energy and core ion temperatures above reference W7-X experimental programs by up to 30%. In a series 4 MW electron cyclotron resonance heating experiments, PPPL Probe Mounted Powder Injector provided 50 ms bursts 100 μm every 350 at estimated quantities ranging from approximately 1 mg/pulse over 30 mg/pulse. For each injection, was observed initially drop...
The role of error fields in stellarators is explored this work through simulations of, and experiments performed on, the Wendelstein 7-X (W7-X) stellarator. Previous experimental results, based on limiter plasmas W7-X, suggest that are small experiment plasmas. In work, we document results from first divertor campaign W7-X with a focus resonant edge island structure. Measurements obtained using thermocouples corroborate earlier correctable, requiring only 5% total rated current trim coil...
The electron temperature and density pedestals tend to vary in their relative radial positions, as observed DIII-D (Beurskens et al 2011 Phys. Plasmas 18 056120) ASDEX Upgrade (Dunne 2017 Plasma Control. Fusion 59 14017). This so-called shift has an impact on the pedestal magnetohydrodynamic (MHD) stability hence height (Osborne 2015 Nucl. 55 063018). present work studies effect of JET ITER-like wall (JET-ILW) baseline low triangularity (δ) unseeded plasmas, similar JET-C discharges. As...
For the first time, optimized stellarator Wendelstein 7-X has operated with an island divertor. An operation regime in hydrogen was found which total plasma radiation approached absorbed heating power without noticeable loss of stored energy. The divertor thermography recorded simultaneously a strong reduction heat load on all targets, indicating almost complete detachment. This stably sustained over several energy confinement times until preprogrammed end discharge. is mainly due to oxygen...
The paper presents procedures which have been developed for a quantitative analysis of the divertor power deposition at Wendelstein 7-X. development these tools is motivated by need to compare and verify scientific engineering predictions with experimental measurements. measurements performed means thermographic diagnostic system, capable exploring heat loads, aim study load symmetry, footprint patterns theoretical expectations, but also investigate leading edges misalignment. In order...
The dynamics and stability of divertor detachment in N 2 seeded, type-I, ELMy H-mode plasmas with dominant NBI heating the JET ITER-like wall device is studied by means an integrated analysis diagnostic data from several systems, classifying relative to ELM times.It thereby possible study response evolution control parameters (SOL input power, upstream density impurity fraction) prevailing during inter-ELM periods effect ELMs on detached divertor.A relatively comprehensive overview achieved,...
Ion cyclotron resonance heating (ICRH) in the hydrogen minority scheme provides central ion and acts favorably on core tungsten transport. Full wave modeling shows that, at medium power level (4 MW), after collisional redistribution, ratio of transferred to ions electrons vary little with (hydrogen) concentration nH/ne but high-Z impurity screening provided by fast temperature increases concentration. The radiated JET discharges has been analyzed a large database covering 2013–2014 campaign....
Operation with a Be/W wall at JET (JET-ILW) has an impact on scenario development and energy confinement respect to the carbon (JET-C). The main differences observed were (1) strong accumulation of W in plasma core (2) need mitigate divertor target temperature avoid sputtering by Be other low Z impurities (3) decrease confinement. A major difference is pedestal pressure, namely reduction which, due profile stiffness also reduced leading degradation global This effect more pronounced β N...
Abstract L to H transition studies at JET have revealed an n = 0, m 1 magnetic oscillation starting immediately the (called M-mode for brevity). While is present a weak ELM-less H-mode regime obtained, with clear increase of density and electron temperature pedestal. It intermediate state between H-mode. In ICRH heated plasmas or low NBI mode pedestal can remain steady (with small oscillations) duration heating phase, order 10 s more. The axisymmetric has period ~0.5–2 ms, poloidal number 1:...
Abstract In high confinement mode, highly shaped plasmas with edge localized modes in JET, and for heating power of 15–17 MW, the fluid code EDGE2D-EIRENE predicts transition to detachment assisted by nitrogen at low field side (LFS) target when more than 50% crossing separatrix between ELMs is radiated divertor chamber, i.e. ~4 MW. This observed both ITER-like wall (JET-ILW) carbon (JET-C) configurations consistent experimental observations within their uncertainty. these conditions, peak...