A5018393291- Magnetic confinement fusion research
- Fusion materials and technologies
- Laser-Plasma Interactions and Diagnostics
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Solar and Space Plasma Dynamics
- Plasma Diagnostics and Applications
- Laser-induced spectroscopy and plasma
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- Astronomical Observations and Instrumentation
- Atomic and Molecular Physics
- Geomagnetism and Paleomagnetism Studies
- Particle Detector Development and Performance
- Laser Design and Applications
- CCD and CMOS Imaging Sensors
- Astro and Planetary Science
- X-ray Spectroscopy and Fluorescence Analysis
- Meteorological Phenomena and Simulations
- Physics of Superconductivity and Magnetism
- Fluid Dynamics and Turbulent Flows
- Spacecraft and Cryogenic Technologies
HUN-REN Centre for Energy Research
2020-2025
Hungarian Academy of Sciences
2009-2024
HUN-REN Wigner Research Centre for Physics
2013-2023
Royal Military Academy
2020
Princeton Plasma Physics Laboratory
2003-2019
Max Planck Institute for Plasma Physics
1995-2019
Max Planck Society
1997-2019
Institute for Particle and Nuclear Physics
2008-2018
Max Planck Institute for Plasma Physics - Greifswald
2005-2018
Institute of Plasma Physics
2018
Wendelstein 7-AS was the first modular stellarator device to test some basic elements of optimization: a reduced Shafranov shift and improved stability properties resulted in β-values up 3.4% (at 0.9 T). This operational limit determined by power balance impurity radiation without noticeable degradation or violent collapse. The partial reduction neoclassical transport could be verified agreement with calculations indicating feasibility concept drift optimization. A full optimization,...
Abstract We present novel experimental evidence of parametric decay instability microwave beams in the plasma edge Wendelstein 7-X stellarator. propose that is sustained by trapping only one daughter wave non-monotonic density profile measured with high spatial resolution within a stationary magnetic island. The power levels and spectral shapes detected signal are reproduced numerical modelling theoretical threshold predicted around 300 kW, comparable observations. predict fraction drained...
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 mechanism governing the impact of mass isotope on plasma confinement is still one main scientific conundrums facing magnetic fusion community after more than thirty years intense research. We have investigated properties local turbulence and long-range correlations in hydrogen deuterium plasmas TEXTOR tokamak. Experimental findings shown a systematic increasing amplitude during transition from to dominated plasmas. These results provide first direct experimental evidence importance...
We report recent experimental results from HL-2A and KSTAR on ELM mitigation by supersonic molecular beam injection (SMBI).Cold particle deposition within the pedestal SMBI is verified in both machines.The signatures of are an frequency increase amplitude decrease.These persist for influence time τI.Here, τI influenced profile to refill.An f /f 0 a decrease energy loss per WELM were achieved machines.Physical insight was gleaned studies density vφ(toroidal rotation velocity) evolution, flux...
An avalanche photodiode based (APD) detector for the visible wavelength range was developed low light level, high frequency beam emission spectroscopy (BES) experiments in fusion plasmas. This solid state has higher quantum efficiency than photomultiplier tubes, and unlike normal photodiodes, it internal gain. paper describes as well noise model of electronic circuit. By understanding sources amplification process, optimal amplifier APD reverse voltage setting can be determined, where...
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 imaging heavy ion beam probe (i-HIBP) diagnostic has been successfully commissioned at ASDEX Upgrade. i-HIBP injects a primary neutral into the plasma, where it is ionized, leading to fan of secondary (charged) beams. These are deflected by magnetic field tokamak and collected scintillator detector, generating strike-line light pattern that encodes information on density, electrostatic potential, plasma edge. first measurements have made, demonstrating proof-of-principle this technique....
A 60 kV neutral lithium diagnostic beam probes the edge plasma of JET for measurement electron density profiles. This paper describes recent enhancements setup, new procedures calibration and protection measures ion gun during massive gas puffs disruption mitigation. New light splitting optics allow in parallel emission measurements with a double entrance slit CCD spectrometer (spectrally resolved) interference filter avalanche photodiode camera (fast fluctuation studies).
Beam emission spectroscopy (BES) measurements of ion-scale density fluctuations in the MAST tokamak are used to show that turbulence correlation time, drift time associated with ion temperature or gradients, particle (ion) streaming along magnetic field, and consistently comparable, suggesting a "critically balanced" determined by local equilibrium. The resulting scalings poloidal radial lengths derived tested. nonlinear inferred from is longer than other times; its ratio scales as...
Observations of ion-scale (kyρi ⩽ 1) density turbulence relative amplitude ≳0.2% are available on the Mega Amp Spherical Tokamak (MAST) using a 2D (8 radial × 4 poloidal channel) imaging beam emission spectroscopy diagnostic. Spatial and temporal characteristics this turbulence, i.e., amplitudes, correlation times, perpendicular lengths apparent phase velocities contours, determined by means analysis. For low-density, L-mode discharge with strong equilibrium flow shear exhibiting an internal...
The ITER Disruption Mitigation System (DMS) Support Laboratory at the Centre for Energy Research, Budapest, Hungary aims characterization of de-sublimation, acceleration and shattering cryogenic pellets, which will be fired upon request into plasma to mitigate detrimental consequences disruptions. test bench includes a fast-acting valve pellet acceleration, releases high-pressure gas on millisecond time scale. is new development since no market existed would have met requirements....
This paper is a summary of some the major results from Wendelstein 7-AS stellarator (W7-AS). W7-AS [G. Grieger et al., Phys. Fluids B 4, 2081 (1992)] has demonstrated feasibility modular coils and pioneered island divertor modeling its three-dimensional characteristics with EMC3/EIRENE code [Y. Feng, F. Sardei Plasma Controlled Fusion 44, 611 (2002)]. It extended operational range to high density (4×1020m−3 at 2.5T) ⟨β⟩ (3.4% 0.9T); it successfully application electron cyclotron resonance...
The electrostatic potential and density fluctuations have been measured at the edge of TEXTOR tokamak by two toroidally distant Langmuir probe arrays.The geodesic acoustic mode (GAM) zonal flows are observed in with a toroidal poloidal symmetric structure.The GAM frequency, , changes monotonically local temperature is close to frequency-dispersion predicted theories.Bispectral analysis shows clear nonlinear coupling between broadband ambient turbulence.The packet has narrow radial extent ≃...
A new beam emission spectroscopy turbulence imaging system has recently been installed onto the MAST spherical tokamak. The utilises a high-throughput, direct coupled optics, and single large interference filter for collection of Doppler shifted Dα from ∼2 MW heating ∼70 keV injection energy. collected light is imaged 2D array detector with 8 × 4 avalanche photodiode sensors which incorporated into custom camera unit to perform simultaneous 14-bit digitization at 2 MHz all 32 channels....
A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The is designed in a way to be capable of measuring either from heating deuterium or diagnostic lithium beam. two beams have somewhat complementary capabilities: edge density profile turbulence measurement with dimensional Two detectors can used parallel: CMOS camera provides overview scene light intensity distribution at maximum few...
A diagnostic instrument is described for the Experimental Advanced Superconducting Tokamak (EAST) measurement of edge plasma electron density profile and turbulence properties. An accelerated neutral lithium beam injected into tokamak Doppler shifted 670.8 nm light emission Li2p-2s transition detected. novel compact setup used, where injection observation take place from same equatorial port radial-poloidal resolution achieved with microsecond time resolution. The direction optimized in...
Diagnosing the density profile at edge of high temperature fusion plasmas by an accelerated lithium beam is a known technique since decades. By knowledge relevant atomic physics rate coefficients, plasma electron can be calculated from relatively calibrated light along beam. Several additional possibilities have already been demonstrated: Charge Exchange Resonance Spectroscopy (CXRS) for ion temperature/flow and Zeeman polarimetry current; therefore Li-beam diagnostic offers wealth...
Abstract Experimental evidence of parametric decay instability (PDI) is observed in the Wendelstein 7-X stellarator, when high-power microwave beams cross a stationary magnetic island at plasma edge. Here, trapping and build-up upper hybrid waves within density bump (measured by alkali beam emission spectroscopy) responsible for reduction power threshold below maximum gyrotron power. In this paper, we provide first experimental connection between mechanism excitation PDI-related signals. We...