A5033214483- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Laser-Plasma Interactions and Diagnostics
- Solar and Space Plasma Dynamics
- Electron and X-Ray Spectroscopy Techniques
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Dust and Plasma Wave Phenomena
- Atomic and Subatomic Physics Research
- Catalytic Processes in Materials Science
- X-ray Spectroscopy and Fluorescence Analysis
- X-ray Diffraction in Crystallography
- Wood Treatment and Properties
- Cultural Heritage Materials Analysis
- Embedded Systems Design Techniques
- Laser-induced spectroscopy and plasma
- Advancements in Photolithography Techniques
- Quantum Chromodynamics and Particle Interactions
- Advanced Data Storage Technologies
- Spectroscopy and Chemometric Analyses
Max Planck Institute for Plasma Physics
2016-2025
Czech Academy of Sciences, Institute of Plasma Physics
2023-2024
Culham Science Centre
2024
Culham Centre for Fusion Energy
2024
Roche (Switzerland)
2023
Max Planck Society
2013-2021
University of Debrecen
2020
Budapest University of Technology and Economics
2005-2017
Chalmers University of Technology
2008-2013
University of Sopron
1998-2012
An overview of the present status research toward final design ITER disruption mitigation system (DMS) is given. The DMS based on massive injection impurities, in order to radiate plasma stored energy and mitigate potentially damaging effects disruptions. this will be extremely challenging due many physics engineering constraints such as limitations port access amount species injected impurities. Additionally, questions relevant remain unsolved mechanisms for mixing assimilation impurities...
Abstract Risdiplam is an oral, survival of motor neuron 2 ( SMN2 ) pre-mRNA splicing modifier approved for the treatment spinal muscular atrophy (SMA). SUNFISH (NCT02908685) Part 2, a Phase 3, randomized, double-blind, placebo-controlled study, investigated efficacy and safety risdiplam in type non‑ambulant 3 SMA. The primary endpoint was met: significantly greater change from baseline 32-item Motor Function Measure (MFM32) total score observed with compared placebo at month 12. After 12...
A new shattered pellet injection system was designed and built to perform disruption mitigation experiments on ASDEX Upgrade. The can inject pellets with diameters of 1, 2, 4, or 8 mm variable lengths over a range L/D ratios ∼0.5-1.5. By using helium deuterium as propellant gas, the be accelerated speeds between 60 750 m/s. velocity slightly depends mass. is capable preparing three in separate barrels at same time. Once by gas pulse, travel through one parallel flight tubes. Each tube...
Abstract This paper discusses the development of a benign termination scenario for runaway electron (RE) beams on ASDEX Upgrade and TCV. A systematic study revealed that low density ( n e ) companion plasma was required to achieve large MHD instability, which expelled confined REs over wetted area allowed conversion magnetic energy radiation. Control achieved via neutral pressure regulation agnostic material injection method. The recombination found be dependent impurity species, quantity RE...
Disruptions in large tokamaks can lead to the generation of a relativistic runaway electron beam that may cause serious damage first wall. To mitigate disruption and suppress application resonant magnetic perturbations has been suggested. In this work we investigate effect on confinement electrons by simulating their drift orbits magnetostatic perturbed fields calculating orbit losses for various initial energies perturbation magnitudes. simulations use TEXTOR-like configuration solve...
We analyze the dynamics of fast electrons in plasmas containing partially ionized impurity atoms, where screening effect bound must be included. derive analytical expressions for deflection and slowing-down frequencies, show that they are increased significantly compared to results obtained with complete screening, already at subrelativistic electron energies. Furthermore, we modifications slowing down frequencies equal importance describing runaway current evolution. Our greatly affect...
Relativistic electron (RE) beams at high current density (low safety factor, qa) yet very low free-electron accessed with D2 secondary injection in the DIII-D and JET tokamak are found to exhibit large-scale MHD instabilities that benignly terminate RE beam. In JET, this technique has enabled termination of MA-level currents without measurable first-wall heating. This scenario thus offers an unexpected alternate pathway achieve mitigation collisional dissipation. Benign is explained by two...
In a shattered pellet injection (SPI) system the penetration and assimilation of injected material depends on speed size distribution SPI fragments. ASDEX Upgrade (AUG) was recently equipped with flexible to study effect these parameters disruption mitigation efficiency. this paper we impact different 1.5D INDEX code. Scans fragment sizes, speeds compositions are carried out for single into AUG H-mode plasmas. We use semi-empirical thermal quench (TQ) onset condition trends. For mixed...
Disruption-generated runaway electron (RE) beams represent a severe threat for tokamak plasma-facing components in high current devices like ITER, thus motivating the search of mitigation techniques. The application 3D fields might aid this purpose and recently was investigated also ASDEX Upgrade experiment by using internal active saddle coils (termed B-coils). Resonant magnetic perturbations (RMPs) with dominant toroidal mode number n = 1 have been applied B-coils, RE specific scenario,...
The most recent experiments of disruption mitigation by massive gas injection in ASDEX Upgrade have concentrated on small-relatively to the past-quantities noble injected, and search for minimum amount necessary thermal loads divertor a significant reduction vertical force during current quench. A scenario generation long-lived runaway electron beam has been established; this allows study dissipation moderate quantities argon injected. This paper presents these results discusses them more...
The role of the COMPASS tokamak in research generation, confinement and losses runaway electron (RE) population is presented. Recently, two major groups experiments aimed at improved understanding control REs have been pursued. First, effects massive gas injection ( Ar/Ne particles) impurity seeding were studied systematically. observed phenomena include generation post-disruption RE beam current conversion from plasma to RE. Zero loop voltage was implemented order study decay simplified...
Abstract Runaway electrons (REs) created during tokamak disruptions pose a threat to the reliable operation of future larger machines. Experiments using shattered pellet injection (SPI) have been carried out at JET investigate ways prevent their generation or suppress them if avoidance is not sufficient. Avoidance possible SPI contains sufficiently low fraction high-Z material, it fired early in advance disruption prone runaway generation. These results are consistent with previous similar...
Disruptions in large tokamaks can lead to the generation of a relativistic runaway electron beam that may cause serious damage first wall. To suppress application resonant magnetic perturbations (RMPs) has been suggested. In this work we investigate effect RMPs on confinement electrons by simulating their drift orbits magnetostatic perturbed fields and calculating transport orbit losses for various initial energies different perturbation configurations. simulations model ITER RMP...
This paper investigates the effect of ITER-like wall (ILW) on runaway electron (RE) generation through a comparative study similar slow argon injection JET disruptions, performed with different materials. In carbon case, plateau is observed, while in current quench slower and negligibly small. The aim to shed light reason for these differences by detailed numerical modelling which factors affected RE formation. post-disruption profile calculated one-dimensional model electric field,...
The synchrotron radiation emitted by runaway electrons in a fusion plasma provides information regarding the particle momenta and pitch-angles of electron population through strong dependence spectrum on these parameters. Information about density its spatial distribution, as well time evolution above quantities, can also be deduced. In this paper, we present spectra for typical avalanching distributions. Spectra obtained distribution are compared with emission mono-energetic prescribed...
Abstract Improved understanding of runaway-electron formation and decay processes are prime interest for the safe operation large tokamaks, dynamics runaway electrons during dynamical scenarios such as disruptions particular concern. In this paper, we present kinetic modelling with time-dependent plasma parameters; in particular, investigate hot-tail generation a rapid drop temperature. With goal studying self-consistent electric-field evolution, also discuss implementation collision...
For the simulation of disruptions in tokamak fusion plasmas, a fluid model describing evolution relativistic runaway electrons and their interaction with background plasma is presented. The overall aim to self-consistently describe nonlinear coupled (REs) instabilities during disruptions. In this model, are considered as separate species which initial seed generated through Dreicer source, eventually grows by avalanche mechanism (further relevant source mechanisms can easily be added)....
Gamma-ray spectroscopy (GRS) has become an established technique to determine properties of the distribution function energetic particles in MeV range, which are fast ions from heating and fusion reactions or runaway electrons born disruptions. In this paper we present a selection recent results where GRS is key investigate physics range particles. These radio-frequency experiments, theoretical models can be tested with unprecedented degree accuracy, disruption mitigation studies, sheds...
To study the runaway electron (RE) dynamics during plasma discharge and develop scenarios for disruption mitigation, a hard x-ray (HXR) spectrometric system has been developed commissioned at ASDEX Upgrade tokamak (AUG). The diagnostic consists of two high-performance spectrometers based on LaBr3(Ce) scintillation detectors supplied with advanced electronics analysis algorithms. These view AUG chamber quasi-radially equatorial plane. measurements were carried out in RE beam generation...
Abstract Runaway electron gamma-ray detection system, a novel hard x-ray (HXR) spectrometer optimized for bremsstrahlung radiation measurement from runaway electrons in fusion plasmas, has been developed. The detector is based on 1‘×1’ LaBr 3 :Ce scintillator crystal coupled with photomultiplier tube. system an energy dynamic range exceeding 20 MeV resolution of 3% at 661.7 keV. gain stable even under severe loads, shift that stays below HXR counting rates excess 1 MCps. performance the...
In support of the ITER disruption mitigation system (DMS), a highly flexible, triple-barrel shattered pellet injection (SPI) was installed at ASDEX Upgrade and tested in 240 dedicated discharges 2022 experimental campaign. Prior to tokamak experiments, commissioned characterised laboratory environment. this paper we discuss experience gained from 2000 launches on freezing launching process for 4 mm 8 diameter pellets made deuterium, neon their mixtures. Different amounts inside as well...
Abstract Alfvén eigenmodes (AEs) and energetic particle modes (EPMs) are often excited by particles (EPs) in tokamak plasmas. One of the main open questions concerning EP driven instabilities is non-linear evolution mode structure. The aim present paper to investigate properties beta-induced AEs (BAEs) geodesic acoustic (EGAMs) observed ramp-up phase off-axis NBI heated ASDEX Upgrade (AUG) discharges. This focuses on changes structure BAEs/EGAMs during chirping phase. Our investigation has...
A new gamma-ray spectrometer with MHz capabilities has been developed to measure the bremsstrahlung emission spectrum in energy band generated by MeV range runaway electrons disruption experiments at ASDEX Upgrade. Properties of are inferred from measured a deconvolution technique, particularly regard their maximum energy. Changes induced electron velocity space unambiguously observed both massive gas injection and resonant magnetic perturbation detector.
Post-disruption runaway electron (RE) beams in tokamaks with large current can cause deep melting of the vessel and are one major concerns for ITER operations. Consequently, a considerable effort is provided by scientific community order to test RE mitigation strategies. We present an overview results obtained at FTU TCV controlling position improve safety repeatability studies such as massive gas (MGI) shattered pellet injections (SPI). show that proposed beam controller (REB-C) implemented...
We derive a formula for the effective critical electric field runaway generation and decay that accounts presence of partially ionized impurities in combination with synchrotron bremsstrahlung radiation losses. show is drastically larger than classical Connor-Hastie field, even exceeds value obtained by replacing free electron density total (including both bound electrons). Using kinetic equation solver an inductive we current after impurity injection expected to be linear time proportional...