A5080374207- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Laser-induced spectroscopy and plasma
- Laser-Plasma Interactions and Diagnostics
- Fusion materials and technologies
- Atomic and Molecular Physics
- Superconducting Materials and Applications
- Solid State Laser Technologies
- Nuclear Physics and Applications
- solar cell performance optimization
- Silicon and Solar Cell Technologies
- Particle accelerators and beam dynamics
- Astro and Planetary Science
- Laser Design and Applications
- Chalcogenide Semiconductor Thin Films
- Advanced oxidation water treatment
- Fluid Dynamics and Turbulent Flows
- Air Quality and Health Impacts
- Electrochemical Analysis and Applications
- Glass properties and applications
- Advanced X-ray Imaging Techniques
- Vehicle emissions and performance
- Photorefractive and Nonlinear Optics
Max Planck Institute for Plasma Physics
2009-2025
Max Planck Institute for Plasma Physics - Greifswald
2010-2024
Czech Academy of Sciences, Institute of Plasma Physics
2024
European Space Research and Technology Centre
2019-2023
Max Planck Society
2008-2021
Forschungszentrum Jülich
2015-2019
University of California, San Diego
2013-2016
Airbus (Germany)
2015
San Diego Association of Governments
2014
University of Colorado Boulder
2014
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 linear plasma device PSI-2 serves as a pilot experiment for the development of components, operational regimes and control systems JULE-PSI, which will be located in nuclear environment allowing studies radioactive toxic samples. is also used fusion reactor relevant plasma-material interaction studies. This contribution describes layout parameters summarizes recent scientific technical progress project, including installation target station sample manipulation analyses.
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...
A significant improvement of plasma parameters in the optimized stellarator W7-X is found after injections frozen hydrogen pellets. The ion temperature post-pellet phase exceeds 3 keV with 5 MW electron heating and global energy confinement time surpasses empirical ISS04-scaling. realized such experiments are significantly above those comparable gas-fuelled discharges. In this paper, we present details these pellet discuss main properties during enhanced phases. Local power balance applied...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics and Mechanism of the Iron(III)-catalyzed Autoxidation Sulfur(IV) Oxides in Aqueous Solution. Evidence for Redox Cycling Iron Presence Oxygen Modeling Overall Reaction MechanismChristian Brandt, Istvan Fabian, Rudi van EldikCite this: Inorg. Chem. 1994, 33, 4, 687–701Publication Date (Print):February 1, 1994Publication History Published online1 May 2002Published inissue 1 February...
Abstract We present recent highlights from the most operation phases of Wendelstein 7-X, advanced stellarator in world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens seconds. Pellet fueling allows plasma reduced ion-temperature-gradient turbulence, during such phases, overall is so (energy often 200 ms) that attained density temperature profiles would not possible less optimized devices, since...
We report experimental studies demonstrating a controlled transition to fully developed broadband turbulence in an argon helicon plasma linear device. show the detailed dynamics during from nonlinearly coupled but distinct eigenmodes at low magnetic fields larger fields. As field (B) is increased B ∼ 40 mT, initially we observe slow smooth changes of system (to 140 mT), followed by sharp (within ∼10 mT) centrally peaked narrow density profiles, strong edge potential gradients and pronounced...
Abstract After a long device enhancement phase, scientific operation resumed in 2022. The main new components are the water cooling of all plasma facing and water-cooled high heat flux divertor units. Water allowed for first long-pulse campaign. A maximum discharge length 8 min was achieved with total heating energy 1.3 GJ. Safe demonstrated attached detached mode. Stable detachment is readily some magnetic configurations but requires impurity seeding small pitch angle within edge islands....
Helicon plasmas are typically associated with a core, radially localized central area of strong ion light emission. Here, we investigate the role electrostatic instabilities that lead to formation classic blue core. We show helicon plasma can also occur without distinct In these conditions, is dominated by low-frequency resistive drift wave (RDW) propagating in electron diamagnetic direction. When intense sharp core present, new global equilibrium state achieved where three separated exist...
Abstract In the Wendelstein 7-X stellarator (W7-X), two related global low-frequency electromagnetic oscil-
lations are observed on many diagnostic systems (e.g. plasma stored energy, Mirnov coils, Langmuir
probes, etc.). The activity is to presence of magnetic islands at certain radii. However, in
contrast initial analyses in earlier works, mode not localized islands,
but rather an m = 1 type outer-core. We observe a strong cross-correlation...
In this work, we present the first experimental evidence of presence zonal flow (ZF) structures in optimized stellarator Wendelstein 7-X. Using an assortment diagnostics, flux surface-uniform, electrostatic oscillations have been measured, showing a radial scale range tens ion gyroradii. As well, indications are found local turbulence being modulated by ZF. Measurements show remarkable agreement with ZF predicted nonlinear gyrokinetic simulations. These results represent direct measurement...
The algorithm for bolometer tomography at Wendelstein 7-X (W7-X) has been recently improved using a novel regularization functional, based on relative gradient smoothing of the sought radiation profile. It validated patterns provided by 3D modeling under real plasma conditions as phantoms and then applied to measurements performed during first divertor operation phase W7-X. following results are presented: (1) edge-localized 2D with clearly resolved magnetic island structures, (2) an up-down...
The neutral beam deposition model in the BEAMS3D code is validated against attenuation data from Wendelstein 7-X (W7-X). A set of experimental discharges where injection system W7-X was utilized were reconstructed. These scanned magnetic configurations and plasma densities W7-X. equilibrium reconstructions performed using STELLOPT which calculates three-dimensional self-consistent ideal magnetohydrodynamic equilibria kinetic profiles. leveraged new capabilities to incorporate electron...
Abstract The soft x-ray tomography diagnostic in the stellarator Wendelstein 7-X consists of twenty pinhole cameras, up–down symmetrically arranged a poloidal, triangular cross-section plasma vessel. emissivity is measured with 16 bit amplitude resolution at 2 MHz sampling rate along 360 lines-of-sight by silicon photodiode arrays. In recent operation campaign data acquisition (DAQ) has been working reliable for conducted pulse lengths <1 min, however DAQ system are ready foreseen 30 min...
Abstract In the previous divertor campaign, Wendelstein 7-X (W7-X) device injected 3.6 MW of neutral beam heating power allowing for achievement densities approaching 2 × 10 20 m −3 , and providing first initial assessment fast ion confinement in a drift optimized stellarator. The injection (NBI) system on W7-X is comprised two boxes with space four radio frequency sources each. reported this work was achieved NI21 box. effect combined electron-cyclotron resonance (ECRH) NBI explored through...
Abstract The energetic particle slowing down model in the BEAMS3D stellarator neutral beam code is compared to analytic models and experimental data from Wendelstein 7-X experiment (W7-X). Recently, first experiments were performed W7-X, providing validation of deposition codes (Lazerson S.A. et al 2020 Nucl. Fusion 60 076020). This work builds upon that work, follows gyro-center orbits neutral-beam-generated fast ions plasma boundary. Slowing times based on measurements diamagnetic energy...
Emissive probes are standard tools in laboratory plasmas for the direct determination of plasma potential. Usually they consist a loop refractory wire heated by an electric current until sufficient electron emission. Recently emissive were used also measuring radial fluctuation-induced particle flux and other essential parameters edge turbulence magnetized toroidal hot [R. Schrittwieser et al., Plasma Phys. Controlled Fusion 50, 055004 (2008)]. We have developed investigated various types...
Efficient laser operation at wavelengths around 1.6 μm is demonstrated in Er (1.1 at. %):YVO₄. The crystal in-band pumped 1536 nm by a fiber laser, resulting maximum slope efficiency of 57.9% with respect to the absorbed pump power and 2.3 W output power. Wavelength tuning birefringent filter wavelength bands suitable for CO₂ lidar applications 1579 1603 could be obtained.
Spectral properties of coherent waves in an argon plasma column are examined using fluctuation data from fast imaging. Visible light ArII line emission is collected at high frame rates a high-speed digital camera. A cross-spectral phase technique allows direct visualization dominant structures as function frequency, well identification azimuthal asymmetries present the system. Experimental dispersion estimates constructed imaging alone. Drift-like identified by comparison with theoretical...
Tungsten plasmas induced by unipolar arcs were investigated using optical emission spectroscopy and imaging, compared with laser-induced tungsten plasmas. The initiated in the linear-plasma simulator PISCES-A at UCSD under fusion relevant conditions. electron temperature density of arc range 0.5–0.7 eV 0.7–2.0 × 1020 m−3, respectively, increased increasing negative bias voltage, but did not correlate surface temperature. In comparison, 0.6–1.4 7 1019–1 1022 respectively.