A5065842944- Magnetic confinement fusion research
- Fusion materials and technologies
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Nuclear reactor physics and engineering
- Laser-induced spectroscopy and plasma
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Astronomical Observations and Instrumentation
- Laser-Matter Interactions and Applications
- Seismic Imaging and Inversion Techniques
- dental development and anomalies
- Laser Design and Applications
- Astro and Planetary Science
- Particle Accelerators and Free-Electron Lasers
- Forensic Anthropology and Bioarchaeology Studies
- Atomic and Subatomic Physics Research
- Drilling and Well Engineering
- Nuclear Materials and Properties
- Dust and Plasma Wave Phenomena
- Geomagnetism and Paleomagnetism Studies
HUN-REN Centre for Energy Research
2021-2025
HUN-REN Wigner Research Centre for Physics
2013-2025
Culham Centre for Fusion Energy
2008-2024
Culham Science Centre
2008-2024
Institute for Atomic Energy Research
2023
University of Pannonia
2022
Princeton Plasma Physics Laboratory
2016-2021
Royal Military Academy
2020
Max Planck Society
1997-2019
Max Planck Institute for Plasma Physics
2018-2019
In ASDEX Upgrade, experimental efforts aim to establish pace making and mitigation of type-I edge localized modes (ELMs) in high confinement mode (H-mode) discharges. Injection small size cryogenic deuterium pellets (∼(1.4 mm)2 × 0.2 mm ≈ 2.5 1019 D) at rates up 83 Hz imposed persisting ELM control without significant fuelling, enabling for investigations well inside the regime. The approach turned out meet all required operational features. was realized with driving frequency ranging from 1...
After completing the main construction phase of Wendelstein 7-X (W7-X) and successfully commissioning device, first plasma operation started at end 2015. Integral start-up using electron cyclotron resonance heating (ECRH) an extensive set diagnostics have been completed, allowing initial physics studies during operational campaign. Both in helium hydrogen, breakdown was easily achieved. Gaining experience with vessel conditioning, discharge lengths could be extended gradually. Eventually,...
The optimized, superconducting stellarator Wendelstein 7-X went into operation and delivered first measurement data after 15 years of construction one year commissioning. Errors in the magnet assembly were confirmend to be small. Plasma was started with 5 MW electron cyclotron resonance heating (ECRH) power five inboard limiters. Core plasma values keV, keV at line-integrated densities achieved, exceeding original expectations by about a factor two. Indications for core-electron-root found....
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...
Injection of cryogenic deuterium pellets has been successfully applied in ASDEX Upgrade for external edge localized mode (ELM) frequency control type-I ELMy H-mode discharge scenarios. A pellet velocity 560 m s−1 and a size about 6 × 1019 D-atoms was selected technical reasons, although even lower masses were found sufficient to trigger ELMs. moderate repetition rate close 20 Hz chosen avoid over-fuelling the core plasma. Pellet sequences up 4 s duration injected into discharges L–H...
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...
The transport of heavy impurities has been investigated at the Wendelstein 7-X stellarator during core electron root confinement (CERC) experiments. Iron atoms were injected via laser blow-off technique and analyzed by VUV x-ray spectrometers. amount iron does not change global plasma parameters but yields strong enough line radiation for detailed studies based on impurity code STRAHL. latter is supplied with neo-classical diffusion convection profiles from drift kinetic equation solver...
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...
Journal Article Aetiological aspects of mandibular tooth agenesis—focusing on the role nerve, oral mucosa, and supporting tissues Get access Inger Kjær, Kjær *Department Orthodontics, School Dentistry, Faculty Health Sciences, University CopenhagenCopenhagen, Denmark Address for correspondence: Department Copenhagen, 20 Nørre Allé, DK-2200 Copenhagen N, Search other works by this author on: Oxford Academic PubMed Google Scholar Gabór Kocsis, Kocsis **Department Dentistry & Oral Surgery,...
A new pellet injection system was installed at JET designed for both fuelling and ELM pacing. The purpose of the pacing section to validate as a suitable tool mitigation in ITER. Pellet confirmed large size scale JET. dynamics triggered ELMs investigated with respect their spontaneous counterparts. Triggered show features also typical several operational regimes. Since none these regimes unsettled by pellets this is strong hint compatibility other plasma control tools. Observations modelling...
Recent experiments at ASDEX Upgrade demonstrate the compatibility of ELM mitigation by magnetic perturbations with efficient particle fuelling inboard pellet injection. persists in a high-density, high-collisionality regime even strongest applied perturbations. Pellets injected into phases trigger no type-I ELM-like events unlike when launched unmitigated ELMy plasmas. Furthermore, absence ELMs results improved efficiency and persistent density build-up. Pellet injection is helpful to access...
Edge-localized mode (ELM) triggering and pacing in an all-metal wall environment shows significant differences to a first-wall configuration containing carbon. Here we report on experiments performed at ASDEX Upgrade revisiting the issue with all plasma-facing surfaces now fully replaced by tungsten. This investigation was motivated experimental findings indicating that ELM becomes more intricate when carbon is metal wall. could no longer be achieved magnetic under conditions previously...
Wendelstein 7-X, a superconducting optimized stellarator built in Greifswald/Germany, started its first plasmas with the last closed flux surface (LCFS) defined by 5 uncooled graphite limiters December 2015. At end of 10 weeks long experimental campaign (OP1.1) more than 20 independent diagnostic systems were operation, allowing detailed studies many interesting plasma phenomena. For example, fast neutral gas manometers supported video cameras (including one fast-frame camera frame rates...
During the installation of new ITER-like wall (ILW) at JET, high frequency pellet injector has been further improved. The launching system is now capable delivering reliable fuelling size pellets from magnetic outboard side up to 15 Hz repetition rate. Pacing can be produced rates 50 but trains suffer some losses during transfer plasma. A significant fraction train arrive plasma when launched outboard, while only a few make it vessel inboard site. Stable and edge-localized mode (ELM) control...
Wendelstein 7-X (W7-X) is a large optimized stellarator (B=2.5T, V=30m3) aiming at demonstrating the reactor relevance of stellarators. In 2015 W7-X will begin its first operation phase (OP1.1) with five inertially cooled inboard limiters made graphite. Assuming heat loads can be spread out evenly between limiters, 1 second discharges 2 MW ECRH heating power could run in OP1.1. The expected plasma parameters sufficient to demonstrate readiness installed diagnostics and even physics program....
The medium size divertor tokamak ASDEX Upgrade (major and minor radii 1.65 m 0.5 m, respectively, magnetic-field strength 2.5 T) possesses flexible shaping versatile heating current drive systems. Recently the technical capabilities were extended by increasing electron cyclotron resonance (ECRH) power, installing 2 × 8 internal magnetic perturbation coils, improving ion range of frequency compatibility with tungsten wall. With reliable suppression large type-I edge localized modes (ELMs)...
Abstract During the two most recent experimental campaigns in advanced stellarator Wendelstein 7-X (W7-X) (Klinger et al 2017 Plasma Phys. Control. Fusion 59 014018; Bosch Nucl. 57 116015; Wolf 102020; Pedersen Plasmas 24 0555030) hydrogen ice pellet injection was performed for first time. In order to investigate potential of fueling W7-X and study particle deposition a large stellarator, blower-gun system installed with 40 pellets capability. The experience gained this will be used...
We present a detailed overview and first results of the new laser blow-off system on stellarator Wendelstein 7-X. The allows impurity transport studies by repetitive controlled injection different tracer ions into plasma edge. A Nd:YAG is used to ablate thin metal film, coated glass plate, with repetition rate up 20 Hz. remote-controlled adjustable optical variation spot diameter enables positioning non-ablated areas target between pulses. During experiments, clear spectral lines from higher...
Wendelstein 7-X is an optimized stellarator with superconducting magnetic field coils that just started plasma operation at the Max-Planck-Institut für Plasmaphysik (IPP) Greifswald. Utilizing electron beam technique first vacuum flux surface measurements were performed during commissioning of magnet system. For configurations investigated so far existence closed and nested surfaces has been validated. All features configuration designed for initial phase, including a predicted island chain,...
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An integrated radiative high performance scenario has been established at ASDEX Upgrade based on simultaneous feedback control of the average divertor neutral particle and power flux in combination with a high, pellet induced frequency edge localized modes (ELMs). This approach is fully compatible present tungsten wall coating covering about 65% plasma facing components intended for application envisaged full-tungsten experiment. In these experiments, recycling effective temperature (derived...