A5039251511- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Laser-induced spectroscopy and plasma
- Nuclear Materials and Properties
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Geomagnetism and Paleomagnetism Studies
- Semiconductor Quantum Structures and Devices
- Heat Transfer and Optimization
- Spacecraft and Cryogenic Technologies
- Metallurgical Processes and Thermodynamics
- Laser Design and Applications
- Atomic and Molecular Physics
- Metal and Thin Film Mechanics
- nanoparticles nucleation surface interactions
- Additive Manufacturing Materials and Processes
- Digital Radiography and Breast Imaging
- Infrared Thermography in Medicine
- Spectroscopy and Laser Applications
- Non-Invasive Vital Sign Monitoring
Forschungszentrum Jülich
2012-2021
Max Planck Institute for Plasma Physics
2015-2019
Max Planck Society
2015-2019
University of Cagliari
2018
Max Planck Institute for Plasma Physics - Greifswald
2018
Huazhong University of Science and Technology
2018
Institute of Plasma Physics
2018
Chinese Academy of Sciences
2018
Atlas Copco (Germany)
2018
Culham Science Centre
2013
Strong mitigation of edge-localized modes has been observed on Experimental Advanced Superconducting Tokamak, when lower hybrid waves (LHWs) are applied to H-mode plasmas with ion cyclotron resonant heating. This demonstrated be due the formation helical current filaments flowing along field lines in scrape-off layer induced by LHW. leads splitting outer divertor strike points during LHWs similar previous observations magnetic perturbations. The change topology qualitatively modeled...
The original goals of the JET ITER-like wall included study impact an all W divertor on plasma operation (Coenen et al 2013 Nucl. Fusion 53 073043) and fuel retention (Brezinsek 083023). ITER has recently decided to install a full-tungsten (W) from start operations. One key inputs required in support this decision was possibility melting melt splashing during transients. Damage type can lead modifications surface topology which could higher disruption frequency or compromise subsequent...
Magnetic turbulence is observed at the beginning of current quench in intended TEXTOR disruptions. Runaway electron (RE) suppression has been experimentally found magnetic larger than a certain threshold. Below this threshold, generated RE inversely proportional to level turbulence. The originates from background plasma and amplitude depends strongly on toroidal field density. These results explain previously threshold for generation have be considered predictions ITER.
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...
For the new ITER-like wall at JET, two infrared diagnostics (KL9B, KL3B) have been installed. These can operate between 3.5 and 5 μm up to sampling frequencies of ∼20 kHz. KL9B KL3B image horizontal vertical tiles divertor. The divertor are tungsten coated carbon fiber composite except central tile which is bulk consists lamella segments. thermal emission lamellae affects surface temperature measurement therefore KL9A has upgraded achieve a higher spatial resolution (by factor 2). A...
For the design and operation of large fusion devices a detailed understanding power exhaust processes is necessary.This paper will give an overview current research on divertor load mechanisms.The results shown are obtained in JET with ITER like wall ASDEX Upgrade tungsten coated plasma facing components.The challenges infrared thermography bulk presented.For steady state heat load, fall-off length λ q JET-ILW compared to empirical scaling found carbon components.A first attempt scale...
Mitigation of type-I edge-localized modes (ELMs) was observed with the application an n = 2 field in H-mode plasmas on JET tokamak ITER-like wall (ILW). Several new findings ILW were identified and contrasted to previous carbon (C-wall) results for comparable conditions. Previous high collisionality C-wall saw little or no influence either 1 fields ELMs. However, recent observations show large ELMs a frequency ∼45 Hz replaced by high-frequency (∼200 Hz) small during field. With ILW,...
Regional and total body heat loss rates of human subjects at rest were measured simultaneously by means an array flux transducers with a tube suit calorimeter. Conditions ranged from thermal comfort to strong cooling. A high degree correlation was found between determined the two independent techniques. For head arms, transducer system less than suit. torso legs, measurements methods equivalent. whole body, yielded rate 87% calorimeter value.
Experiments in the JET tokamak equipped with ITER-like wall (ILW) revealed that inner and outer target plate at location of strike points represent after one year operation intact tungsten (W) surfaces without any beryllium (Be) surface coverage. The dynamics near-surface retention, implantation, desorption recycling deuterium (D) divertor plasma discharges are determined by W plates. As plasma-facing components (PFCs) not actively cooled, temperature (Tsurface) is increasing exposure,...
The paper presents experimental observations and simulations for the effects of toroidal plasma current on divertor power depositions W7-X.With increasing accompanying changes in island geometry result a sweep strike line redistribution heat flux footprints.Good agreement between experiments, which partly used electron cyclotron drive to generate an additional contribution, modelling using field tracing vacuum magnetic fields including ad-hoc axis is found both standard low-iota configurations.
Diverted plasmas in the stellarator W7-X are investigated using a hopping poloidal correlation reflectometer and set of Langmuir probes to investigate plasma edge scrape off layer at two different toroidal positions cross sections, respectively. The properties studied as function magnetic configurations parameters. experimentally determined radial position inversion point electric field is compared with calculations. For certain remnant island observed current. Different methods determine...
Wendelstein 7-X (W7-X), started operation in December 2015 with a limiter configuration. In conjunction the multi-purpose manipulator, carrier for fast reciprocating probe systems, combined has been installed. This is able to measure local electron temperatures and densities, magnetic field, electric field plasma flow. These parameters are very useful ascertaining edge perfomance. addition, line tracing feature of W7-X webservices was used calculate connection length along path probe, each
A long-pulse high confinement plasma regime known as H-mode is achieved in the Experimental Advanced Superconducting Tokamak (EAST) with a record duration over 30 s, sustained by Lower Hybrid wave Current Drive (LHCD) advanced lithium wall conditioning and divertor pumping. This characterized co-existence of small Magneto-Hydrodynamic (MHD) instability, i.e., Edge Localized Modes (ELMs) continuous quasi-coherent MHD mode at edge. We find that LHCD provides an intrinsic boundary control for...
The lower hybrid wave (LHW) heating experiments at the Experimental Advanced Superconducting Tokamak (EAST) show a wide range of similarities to effects known from applied resonant magnetic perturbations (RMPs) by in-vessel or external perturbation coils. These observations suggest current flow understood be along scrape-off layer (SOL) field lines; here called helical filaments (HCFs). For better understanding experimental observations, model incorporate HCFs in topology has been developed....
A group of edge diagnostics and modelling has been developed for investigation synergy between 3D physics plasma-wall interactions on Wendelstein 7-X (W7-X). Two endoscopes have designed visible ultraviolet spectroscopy tomography the plasma edge, along with infrared thermography divertor tiles. 2D profiles impurities (e.g. helium, carbon) will be measured by two viewing island region in a spatial resolution <2 mm. multipurpose manipulator, which is used as carrier either probe head...
Recent experiments from the Experimental Advanced Superconducting Tokamak (EAST) show that lower hybrid waves (LHWs) can profoundly change magnetic topology by inducing helical current filaments flowing along field lines in scrape-off layer. Here, it is investigated for first time how these perturbations caused LHWs affect edge plasma transport utilizing three-dimensional Monte Carlo code EMC3-EIRENE, both double-null and single-null configurations. The 3D structure reflected properties, due...
Three dimensional (3D) divertor particle flux footprints induced by the lower hybrid wave (LHW) have been systematically investigated in EAST superconducting tokamak during recent experimental campaign. We find that striated (SPF) peaks away from strike point (SP) closely fit pitch of edge magnetic field line for different safety factors q95, as predicted a tracing code taking into account helical current filaments (HCFs) scrape-off-layer (SOL). As LHW power increases, it requires fuelling...
During its second operational campaign (OP 1.2a) W7-X operated with an edge island divertor. Much higher densities (1020m−3) than in to the previous, limiter were achieved. In order asses this improved performance and nature of transport regard expected other parameters such as electron ion temperature, electric field plasma flow, measurements at conducted reciprocating probe, mounted on a Manipulator. The probe contains set Langmuir pins, Mach probes, compensation coils 3D pick up for...
This paper presents a demonstration experiment of ion cyclotron wall conditioning (ICWC) on TEXTOR covering all ITER aims and discusses the implications for ITER. O2/He-ICWC applied to erode carbon co-deposits removed 6.6 × 1021 C-atoms (39 pulses, 158 s cumulated discharge time). Large oxygen retention (71% injected oxygen) prevented subsequent ohmic initiation. Plasma operation was recovered by 1h47 multi-pulse D2-ICWC procedure including pumping time between pulses with duty cycle 2 s/20...
Wendelstein 7-X (W7-X) was operated successfully with the first divertor plasma in operation phase 1.2a (OP1.2a). A new combined probe head, developed and installed on multiple-purpose manipulator, is able to measure edge profiles (), variation of magnetic field, poloidal radial turbulence structures. The scrape-off layer (SOL) parameters two configurations (standard high mirror) are good agreement island structure field line connection length calculated by tracer. In both standard mirror...