A5000779217- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Spacecraft and Cryogenic Technologies
- Nuclear Materials and Properties
- Laser-induced spectroscopy and plasma
- Nuclear Physics and Applications
- Particle Accelerators and Free-Electron Lasers
- High-Energy Particle Collisions Research
- Underwater Vehicles and Communication Systems
- Textile materials and evaluations
- Catalytic Processes in Materials Science
- Semiconductor materials and devices
- Vehicle Noise and Vibration Control
- Robotics and Sensor-Based Localization
- Plasma and Flow Control in Aerodynamics
- Advanced MRI Techniques and Applications
- Advanced Radiotherapy Techniques
- Geophysics and Gravity Measurements
Max Planck Institute for Plasma Physics
2016-2025
Culham Centre for Fusion Energy
2024
Fusion Academy
2022-2023
Fusion (United States)
2022-2023
University of Milano-Bicocca
2022
Culham Science Centre
2022
Max Planck Society
2015-2021
National Centre for Nuclear Research
2021
Technical University of Munich
2016-2019
Universität Innsbruck
2014
Abstract The most efficient and promising operational regime for the International Thermonuclear Experimental Reactor tokamak is high-confinement mode. In this regime, however, periodic relaxations of plasma edge can occur. These edge-localized modes pose a threat to integrity fusion device. Here we reveal strong impact energetic ions on spatio-temporal structure in tokamaks using nonlinear hybrid kinetic–magnetohydrodynamic simulations. A resonant interaction between fast at electromagnetic...
Abstract Future fusion reactors require a safe, steady state divertor operation. The required detached operation is, in tokamaks with metal walls, usually achieved by seeding of impurities, such as nitrogen. With strong levels, the dominant radiation is emitted from small, poloidally localized volume inside confined region, vicinity X-point. location radiating observed to vary relative X-point depending on and power i.e. degree detachment. At ASDEX Upgrade tokamak, position radiator can be...
Abstract The tokamak à configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system address critical issues in preparation for ITER a fusion power plant. For the 2019–20 campaign configurational flexibility has been enhanced with installation of removable divertor gas baffles, diagnostic capabilities an extensive set upgrades new dual frequency gyrotrons. baffles reduce coupling between main chamber allow detailed...
Abstract Based on particle and energy balances, a reduced model is derived for the physical mechanisms leading to occurrence of stable unstable X-point radiators (XPRs), latter also known as marfes. The roles neutral deuterium density in divertor region initiating XPRs highlighted. An access condition formulated whose parameter dependencies are consistent with experimental observations which could apply process detachment. With an exponential increase recombination rate at low temperature,...
Abstract The quasi-continuous exhaust (QCE) regime, formerly known as either type-II ELM or small regime is studied in ASDEX Upgrade. a natural type-I ELM-free H-mode. operational space of QCE discharges Upgrade with respect to their separatrix conditions and power capabilities are presented. A significant broadening the fall-off length observed, correlating an increased density pressure. Moreover, possible reactor relevance this demonstrated by expanding low edge safety factor demonstrating...
The search for scenarios in which tolerable power exhaust is combined with good confinement must involve high separatrix densities. We present here the first infrared thermography measurements at ASDEX Upgrade a density, H-mode regime no type-I ELMs are present. This was formerly called type-II ELM or small to distinguish it from ELMs. report on broadening of fall-off length this up factor four compared low density inter conditions. correlated an increased filament detection rate as well...
Abstract In magnetic confinement thermonuclear fusion the exhaust of heat and particles from core remains a major challenge. Heat leaving are transported via open field lines to region reactor wall, called divertor. Unabated, particle fluxes may become intolerable damage Controlled ‘plasma detachment’, regime characterized by both large reduction in plasma pressure temperature at divertor target, is required reduce onto Here we report systematic approach towards achieving this critical need...
Future fusion reactors require a safe, steady-state divertor operation. With deep detachment, which is typically induced by impurity seeding, the radiation concentrates in small region at X-point or on closed flux surfaces above X-point. This so-called radiator (XPR) moves further inside confined with increasing seeding and location can be actively controlled. At AUG, parameter space for operation an XPR was significantly extended, using active feedback location. The observed nearly whole...
Abstract Using newly developed spectroscopic models to measure the divertor concentration of Ne and Ar, it is shown that experimental detachment threshold on ASDEX Upgrade with Ar-only mixtures Ar+N or Ne+N scales as expected in comparison an analytical equation derived by Kallenbach et al (2016 Plasma Phys. Control. Fusion 58 045013). However, found Ar radiates more efficiently less scrape-off layer than model predicts. By separately increasing neutral beam injection power cutting impurity...
We present a novel concept to tackle the power exhaust challenge of magnetically confined fusion plasma. It relies on prior establishment an X-point radiator that dissipates large fraction before it reaches divertor targets. Despite spatial proximity magnetic X point confinement region, this singularity is far away from hot plasma in coordinates and therefore allows coexistence cold dense with high potential radiate. In compact radiative (CRD) target plates are placed close point. here...
Abstract In order to extend the enhanced D-Alpha H-mode future devices, it is crucial understand properties of main signature this regime, quasicoherent mode (QCM), that likely clamps pressure gradient below ideal magnetohydrodynamic limit. The turbulent character QCM investigated with scanning probes in ASDEX Upgrade. Analysis reveals multi-faced spans both confined region (where radial electric field negative) and near scrape-off layer (SOL) positive). Fluctuations density potential at...
Abstract The research program of the TCV tokamak ranges from conventional to advanced-tokamak scenarios and alternative divertor configurations, exploratory plasmas driven by theoretical insight, exploiting device’s unique shaping capabilities. Disruption avoidance real-time locked mode prevention or unlocking with electron-cyclotron resonance heating (ECRH) was thoroughly documented, using magnetic radiation triggers. Runaway generation high- Z noble-gas injection runaway dissipation...
The plasma response from an external n = 2 magnetic perturbation field in ASDEX Upgrade has been measured using mainly electron cyclotron emission (ECE) diagnostics and a rigid rotating field. To interpret ECE ECE-imaging (ECE-I) measurements accurately, forward modeling of the radiation transport combined with ray tracing. data is compared to synthetic generated 3D ideal magnetohydrodynamics (MHD) equilibrium calculated by VMEC. amplitudes helical displacement around low side midplane are...
Abstract The Tokamak à Configuration Variable (TCV) tokamak is in the midst of an upgrade to further its capability investigate conventional and alternative divertor configurations. To that end, modular removable gas baffles have been installed decrease coupling between plasma core. primarily seek suppress transit recycling neutrals closed flux surfaces. A first experimental campaign with has shown baffled remains compatible a wide range configurations including snowflake super- X divertors....
The formation of the equilibrium radial electric field (Er) has been studied experimentally at ASDEX Upgrade (AUG) in L-modes “favorable” (ion ∇ B-drift toward primary X-point) and “unfavorable” away from drift configurations, view its impact on H-mode access, which changes with configurations. Edge electron ion kinetic profiles impurity velocity mean-field Er across separatrix are investigated, employing new improved measurement techniques. experimental results compared to local...
Abstract Experiments on ASDEX Upgrade (AUG) in 2021 and 2022 have addressed a number of critical issues for ITER EU DEMO. A major objective the AUG programme is to shed light underlying physics confinement, stability, plasma exhaust order allow reliable extrapolation results obtained present day machines these reactor-grade devices. Concerning pedestal physics, mitigation edge localised modes (ELMs) using resonant magnetic perturbations (RMPs) was found be consistent with reduction linear...
Abstract Building on prior analysis of ASDEX Upgrade (AUG) experiments (Henderson et al 2023 Nucl. Fusion 63 086024), this study compares simple analytical formula predictions for divertor detachment onset and reattachment timescales in JET experiments. Detachment primarily scales with neutral pressure, impurity concentration, power directed to the targets, machine size, integral perpendicular decay length. experiments, focusing seeding mixtures Ne Ar, align predictions. Radiation...
Abstract A set of dedicated H-mode discharges with constant heating power combining Neutral Beam Injection and Electron Cyclotron Resonance Heating have been executed at the ASDEX Upgrade tokamak using a high triangularity magnetic geometry in order to investigate impact filamentary transport divertor non-divertor components. The evolution upstream scrape-off layer (SOL) profiles correlated separatrix quantities, mostly turbulence control parameter <mml:math...
The Alfvén instability nonlinearly excited the energetic-particle-driven geodesic acoustic mode on ASDEX-Upgrade tokamak, as demonstrated experimentally. mechanism of excitation and nonlinear evolution is not yet fully understood. In present work, a first-principles simulation using MEGA code investigated properties in both linear growth saturated phases. Here we show that successfully reproduced coexistence these two modes, agreed with experimental results well. Conclusive evidence showed...
Abstract Understanding the transport processes that determine plasma profile widths in scrape-off layer (SOL) and divertor region of tokamaks is crucial for successful power particle exhaust management future devices. Plasma from SOL into Private Flux Region (PFR) broadens profiles could mitigate challenge. Analysis ion current profiles, measured by Langmuir probes ASDEX Upgrade (AUG) tokamak, shows width PFR, normalized flux expansion between outer target midplane, about \SI{1.5}{mm} L-mode...
Abstract 2D profiles of electron density and neutral temperature are inferred from multi-delay Coherence Imaging Spectroscopy data divertor plasmas using a non-linear inversion technique. The inference is based on imaging the spectral line-broadening Balmer lines can differentiate between Doppler Stark broadening components by measuring fringe contrast at multiple interferometric delays simultaneously. model has been applied to images generated simulated evaluate its performance. Typical...
Abstract JET returned to deuterium-tritium operations in 2023 (DTE3 campaign), approximately two years after DTE2. DTE3 was designed as an extension of JET's 2022-2023 deuterium campaigns, which focused on developing scenarios for ITER and DEMO, integrating in-depth physics understanding control schemes. These were evaluated with mixed D-T fuel, using the only remaining tritium-capable tokamak until its closure 2023. A core-edge-SOL integrated H-mode scenario developed tested D-T, showing...
Abstract On the basis of several recent breakthroughs in fusion research, many activities have been launched around world to develop power plants on fastest possible time scale. In this context, high-fidelity simulations plasma behavior large supercomputers provide one main pathways accelerating progress by guiding crucial design decisions. When it comes determining energy confinement a magnetic device, which is key quantity interest, gyrokinetic turbulence are considered approach choice –...