A5060883547- Magnetic confinement fusion research
- Solar and Space Plasma Dynamics
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Superconducting Materials and Applications
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Geomagnetism and Paleomagnetism Studies
- Astronomical Observations and Instrumentation
- High-pressure geophysics and materials
- Laser-induced spectroscopy and plasma
- Particle Accelerators and Free-Electron Lasers
- Geophysics and Sensor Technology
- Ion-surface interactions and analysis
- High voltage insulation and dielectric phenomena
- Geophysics and Gravity Measurements
- Electromagnetic Launch and Propulsion Technology
- Advanced Materials Characterization Techniques
- Metal Forming Simulation Techniques
- Chaos control and synchronization
- Magnetic Properties of Alloys
- Fluid Dynamics and Turbulent Flows
- Complex Systems and Time Series Analysis
- Aluminum Alloy Microstructure Properties
Max Planck Institute for Plasma Physics - Greifswald
2016-2024
Max Planck Institute for Plasma Physics
2003-2021
Max Planck Society
2003-2021
Princeton Plasma Physics Laboratory
2021
HUN-REN Centre for Energy Research
2021
GSI Helmholtz Centre for Heavy Ion Research
2001
Research Association for Combustion Engines
2000
Tokyo Institute of Technology
1999
Friedrich-Alexander-Universität Erlangen-Nürnberg
1993
Abstract Research on magnetic confinement of high-temperature plasmas has the ultimate goal harnessing nuclear fusion for production electricity. Although tokamak 1 is leading toroidal magnetic-confinement concept, it not without shortcomings and community therefore also pursued alternative concepts such as stellarator. Unlike axisymmetric tokamaks, stellarators possess a three-dimensional (3D) field geometry. The availability this additional dimension opens up an extensive configuration...
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...
Employing a two-dimensional simulation model, this paper presents suitable design for an experiment to study metallization of hydrogen in heavy-ion beam imploded multilayered cylindrical target that contains layer frozen hydrogen. Such will be carried out at the upgraded synchrotron facility (SIS-18) Gesellschaft für Schwerionenforschung, Darmstadt by end year 2001. In these calculations we consider uranium available SIS-18. Our show it may possible achieve theoretically predicted physical...
The magnetic diagnostic system at the Wendelstein 7-X stellarator includes three diamagnetic loops to measure flux changes in plasma. Their signals are directly related plasma energy. design with respect materials, component cooling and data acquisition is built be fully steady-state capable within harsh environment of a fusion device. During first operational phase, two have been put into operation, each them close one up-down symmetric main planes column bean-shaped triangular-shaped...
In this paper is presented, with the help of sophisticated two-dimensional hydrodynamic simulations, a suitable design optimized parameters for heavy-ion beam-matter interaction experiment that will be carried out at Gesellschaft fur Schwerionenforschung (GSI) Darmstadt by end year 2001 when upgrade existing accelerator facility completed. Our simulations show upgraded beam capable generating strong shocks in solid targets compress target material to supersolid densities and generate...
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.
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 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...
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 Intrinsic, diffusion-driven toroidal (bootstrap) currents between −7 and 17 kA were measured in the optimised stellarator Wendelstein 7-X (W7-X) for several magnetic configurations at line-integrated plasma densities 2 × 10 19 1.6 20 m −2 heating powers 0.5 6 MW. The sign of bootstrap current changes with field reversal, its magnitude decreases mirror term rotational transform configuration as well density, increases power. Both absolute values dependencies agree neoclassical...
Abstract At the W7-X stellarator, bolometer system has measured an intensive radiation zone in inner plasma region (at a normalized radius ρ ∼ 0.3–0.4) hydrogen generated by electron cyclotron resonance heating; it differs from normal distribution with edge-localized emission zone. Spectroscopic diagnostics have recorded high-Z elements such as iron. This phenomenon happens phases after gas supply turn-off, which results all impurity relevant diagnostic signals increasing for several...
Abstract The role of toroidal plasma currents for the island divertor scrape-off layer in stellarator Wendelstein 7-X is investigated using reciprocating electric probes. Experiments show that small amounts (of a few kA) current are sufficient to significantly affect conditions, whereas higher above 10kA result more drastic changes. This behavior linked effect on rotational transform profile, which can significant shifts edge magnetic islands. These interaction islands with and eventually...
Abstract To support the scenario design for upcoming long-pulse high-performance campaign of Wendelstein 7-X, this work presents a study high-beta full-field 3D equilibria obtained with HINT code. For three magnetic configurations different edge- ι , effects both overall pressure and profile changes on topology are analyzed. Anisotropic diffusion modeling is used to obtain estimates conductive heat load distribution divertor other plasma-facing components in finite-beta configurations....
A theory-based model for the control of plasma currents steady-state operation in W7-X is proposed and intended model-based control. The conceptual outline implies strength physics-based models: it offer approaches applicable to future conditions fusion devices or next-step machines. application at extrapolated settings related validity range theory model. Therefore, predictive power models could be larger than data-driven limitations can predicted from prediction bootstrap W7-X. predicts...