A5004506663- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Plasma Diagnostics and Applications
- Spacecraft and Cryogenic Technologies
- Advanced Fiber Laser Technologies
- Scientific Measurement and Uncertainty Evaluation
- Nuclear Physics and Applications
- Physics of Superconductivity and Magnetism
- Radiation Detection and Scintillator Technologies
- Atomic and Subatomic Physics Research
Czech Academy of Sciences, Institute of Plasma Physics
2019-2025
Culham Centre for Fusion Energy
2024
Czech Academy of Sciences
2024
Institute of Nuclear Physics, Polish Academy of Sciences
2021
Charles University
2020-2021
COMPASS Upgrade is a new medium size, high magnetic field tokamak (R = 0.9 m, Bt 5 T, Ip 2 MA) currently under design in the Czech Republic. It will provide unique capabilities for addressing some of key challenges plasma exhaust physics, advanced confinement modes and configurations as well testing facing materials liquid metal divertor concepts. This paper contains an overview preliminary engineering main systems (vacuum vessel, central solenoid poloidal coils, toroidal support structure,...
Abstract The fast-ion phase-space distribution function in axisymmetric tokamak plasmas is completely described by the three constants of motion: energy, magnetic moment and toroidal canonical angular momentum. In this work, observable regions constants-of-motion phase-space, given a diagnostic setup, are identified explained using projected velocities fast ions along lines-of-sight as proxy for several diagnostics, such <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Within the EUROfusion MST1 work package, a series of experiments has been conducted on AUG and TCV devices to disentangle role plasma fueling shape for onset small ELM regimes. On both devices, regimes with high confinement are achieved if only two conditions fulfilled at same time. Firstly, density separatrix must be large enough (), leading pressure profile flattening separatrix, which stabilizes type-I ELMs. Secondly, magnetic configuration close double null (DN), reduction shear in...
Abstract Within the 9th European Framework programme, since 2021 EUROfusion is operating five tokamaks under auspices of a single Task Force called ‘Tokamak Exploitation’. The goal to benefit from complementary capabilities each machine in coordinated way and help developing scientific output scalable future largre machines. programme this ensures that ASDEX Upgrade, MAST-U, TCV, WEST JET (since 2022) work together achieve objectives Missions 1 2 Roadmap: i) demonstrate plasma scenarios...
Abstract Tomographic reconstructions of a 3D fast-ion constants-of-motion phase-space distribution function are computed by inverting synthetic signals based on projected velocities the fast ions along diagnostic lines sight. A spectrum is key element formation in D-alpha spectroscopy, collective Thomson scattering, and gamma-ray neutron emission it can hence serve as proxy for any these. The functions parameterised three constants motion, kinetic energy, magnetic moment toroidal canonical...
Abstract The COMPASS upgrade tokamak (Panek et al 2017 Fusion Eng. Des. 123 11–16) will be a of major radius R 0 = 0.894 m with the possibility to reach high field ( B t ∼ 5 T) and current I p 2 MA). machine should see its first plasma in 2023 H-mode obtained from 2025. main auxiliary heating system used access 4 MW neutral beam injection (NBI) power. NBI have nominal energy 80 keV, maximum tan 0.65 create population well-confined energetic D ions. In this contribution, our modelling studies...
Abstract Analysis of heat fluxes in scrape-off layer (SOL) plasma is important for the prediction divertor tile loads future reactor-sized tokamak machines. Typically, radial flux profile can be accurately characterized by decay length parameter λ q . The predictions are then based on dependence and machine parameters. In recent years, several empirical scaling models were derived from a collective database lengths observed large tokamaks as well two spherical tokamaks. Most recently, report...
Abstract COMPASS addressed several physical processes that may explain the behaviour of important phenomena. This paper presents results related to main fields research obtained in recent two years, including studies turbulence, L–H transition, plasma material interaction, runaway electron, and disruption physics: Tomographic reconstruction edge/SOL turbulence observed by a fast visible camera allowed visualize turbulent structures without perturbing plasma. Dependence power threshold on...
Abstract We introduce detailed numerical modelling of the fast neutral particles inside duct a new beam injector (NBI) recently installed at COMPASS tokamak (major radius <?CDATA $R_0 = 0.56\,\mathrm{m}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>R</mml:mi> <mml:mn>0</mml:mn> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>0.56</mml:mn> <mml:mrow> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:math> , vessel midplane minor $a...
Abstract This work presents the first analysis of disruptive locked mode (LM) triggered by dynamics a confinement change. It shows that, under certain conditions, LM threshold during transient is significantly lower than expected from steady states. We investigate sensitivity to controlled n = 1 error field (EF) activated prior L-H transition in COMPASS tokamak, at q 95 ∼ 3, β N 1, and using EF coils on high-field side vessel. A for penetration subsequent identified, which no significant...
Abstract Measurements using a recently installed edge fast-ion D-alpha (FIDA) diagnostic at the ASDEX Upgrade tokamak show clear effect of localised modes (ELMs) on passive FIDA signals. While reduction in emission is observed scrape-off layer (SOL) region, measurements close to last closed flux surface an increase signals shortly after ELMs, followed by decrease. The decrease provides sign losses SOL, while can be explained enhanced neutral density during ELMs inside plasma. In addition,...
Abstract Here we present a new method that allows the determination of background neutral density profiles based on measurements from particle analyzers (NPA). Bayesian optimization is used to obtain reliable 5-parameter representation inferred profiles. The has been benchmarked using forward modelling FIDASIM against measured data. systematic errors coming assumptions made in analysis were evaluated and they are lower than ≲5%. tested data ASDEX Upgrade tokamak. When reconstructed profiles,...
Abstract Two identical neutral beam injectors (NBIs) have been installed on the COMPASS tokamak. Each of them is capable producing a deuterium (or hydrogen, helium) with nominal power up to 400 kW at 40 keV. Since tokamak compact machine, design beams was carefully optimized fit through narrow ports However, once are operated out scope their optimal parameters, additional losses occur due scraping. This article investigates amount loss The calculated using models and measured parameters....
This work presents the first analysis of disruptive locked mode (LM) triggered by dynamics a confinement change. It shows that, under certain conditions, LM threshold during transient is significantly lower than expected from steady states. We investigate sensitivity to controlled $n = 1$ error field (EF) activated prior L-H transition in COMPASS tokamak, at $q_{95} \approx 3$, $\beta_N 1$, and using EF coils on high-field side vessel. A for penetration subsequent identified, which no...
This paper presents an experimental characterization of the local plasma parameters in COMPASS open divertor deuterium, L-mode plasmas by means Langmuir probes during neutral beam injection (NBI) heating. The effect NBI heating core on is investigated under different configurations and directions magnetic field current for line-averaged electron densities. At low densities below 6 × 1019 m-3, a power level does not lead to any significant changes region. It also found that reversed influence...