T. Markovič
A5080610447- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Solar and Space Plasma Dynamics
- Physics of Superconductivity and Magnetism
- GNSS positioning and interference
- Fault Detection and Control Systems
- Nuclear Engineering Thermal-Hydraulics
- Plasma Diagnostics and Applications
- Neural Networks and Applications
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Magnetic Field Sensors Techniques
- Spacecraft and Cryogenic Technologies
- Particle Accelerators and Free-Electron Lasers
- Quantum and electron transport phenomena
- Meteorological Phenomena and Simulations
- Gas Dynamics and Kinetic Theory
- Seismic Waves and Analysis
- High-Energy Particle Collisions Research
- Image and Signal Denoising Methods
Czech Academy of Sciences, Institute of Plasma Physics
2016-2025
CEA Cadarache
2024
Institut de Recherche sur la Fusion par Confinement Magnétique
2024
Culham Science Centre
2024
Culham Centre for Fusion Energy
2024
Charles University
2015-2023
Royal Military Academy
2020
Czech Technical University in Prague
2013
This paper summarizes the status of COMPASS tokamak, its comprehensive diagnostic equipment and plasma scenarios as a baseline for future studies. The former COMPASS-D tokamak was in operation at UKAEA Culham, UK 1992–2002. Later, device transferred to Institute Plasma Physics Academy Sciences Czech Republic (IPP AS CR), where it installed during 2006–2011. Since 2012 has been full with Type-I Type-III ELMy H-modes base scenario. enables together ITER-like shape flexible NBI heating system...
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 In magnetic fusion devices, error field (EF) sources, spurious perturbations, need to be identified and corrected for safe stable (disruption-free) tokamak operation. Within Work Package Tokamak Exploitation RT04, a series of studies have been carried out test the portability novel non-disruptive method, designed tested in DIII-D (Paz-Soldan et al 2022 Nucl. Fusion 62 126007), perform an assessment model-based EF control strategies towards their applicability ITER. this paper,...
Abstract The amplitude of locked instabilities, likely magnetic islands, seen as precursors to disruptions has been studied using data from the JET, ASDEX Upgrade and COMPASS tokamaks. It was found that thermal quench, often initiates disruption, is triggered when reached a distinct level. This information can be used determine thresholds for simple disruption prediction schemes. measured in part depends on distance perturbation measurement coils. Hence threshold mode location (i.e. rational...
Asymmetrical disruptions may occur during ITER operation and they be accompanied by large sideways forces rotation of the asymmetry. This is particular concern because resonance rotating asymmetry with natural frequencies vacuum vessel (and other in-vessel components) could lead to dynamic amplification forces. A significant fraction non-mitigated JET have toroidally asymmetric currents that flow partially inside plasma surrounding ('wall'). The toroidal asymmetries (otherwise known as...
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...
This paper presents a multi-machine, multi-parameter scaling law for the n = 2 core resonant error field threshold that leads to penetration, locked modes, and disruptions. Here, is toroidal harmonic of non-axisymmetric (EF). While density scalings have been reported by individual tokamaks in past, this work performs regression across comprehensive range densities, fields, pressures accessible three devices using common metric quantify EF each device. The used amount overlap between an...
In fusion devices strong interest is deserved to the edge filament transport both related turbulent and ELMy structures, because they are believed provide important interaction with plasma facing components divertor plates. Among their features also electromagnetic (EM) properties expected play an role in particular for high beta regimes future devices. The presence of ELM inter-ELM filaments were detected during H-mode discharges COMPASS device Scrape-Off Layer, where a new probe head was...
Multiple quasicoherent electromagnetic modes with steady-state frequency and different nature location were observed in the COMPASS tokamak (R = 0.56 m, <a > 0.2 m) at Bt 1.14 T Co-NBI (PNBI 0.2–0.5 MW, Eb 32 keV) frequencies 5 kHz < f 250 kHz. Modes both low high confinement (L- H-modes) plasmas. Lower 50 identified as m tearing kink MHD modes, while higher considered having Alfvénic nature. Unexpectedly, such only H-mode, neutral beam injector-assisted Ohmic, so mode driving force is not...
The significant role of magnetic perturbations in mitigation and losses runaway electrons (REs) was documented dedicated experimental studies RE at the COMPASS tokamak. REs are produced both low density quiescent discharges disruptions triggered by massive gas injection (MGI). seed beginning discharge on subsequent population proved significant. Modulation MHD instabilities observed several characteristic frequencies, as well field oscillations related to power supplies. Magnetic islands...
This paper presents two scenarios used for generation of a runaway electron (RE) beam in the COMPASS tokamak with focus on decay phase and control beam. The first scenario consists massive gas injection argon into current ramp-up phase, leading to disruption accompanied by plateau generation. In second scenario, smaller amount is order isolate RE from high-temperature plasma. performances radial vertical position feedback were experimentally studied analysed. role energy stability seems be...
The 3-D field induced relativistic runaway electron (RE) loss has been simulated for DIII-D and COMPASS plasmas, utilizing the MARS-F code incorporated with recently developed updated RE orbit module (REORBIT). Modeling shows effectively 100% of a post-disruption, high-current beam in due to 1 kG level magnetic perturbation produced by fast growing n = resistive kink instability. This complete is shown be independent particle energy or initial location particles configuration space. Applied...
Abstract Microsecond probe measurements of the electron temperature during tokamak edge localised mode (ELM) instability show that peak values significantly exceed those obtained by conventional techniques. The temperatures measured at plasma facing component (divertor) are around 80% initial value (at pedestal). This challenges current understanding, where only several percent pedestal divertor. Our results imply a negligible energy transfer from electrons to ions ELM instability, and...
Abstract The understanding of the halo current properties during disruptions is key to design and operate large scale tokamaks in view thermal electromagnetic loads that they entail. For first time, we present a fully self-consistent model for simulations including neutral particles sheath boundary conditions. used simulate vertical displacement events (VDEs) occurring COMPASS tokamak. Recent experiments have shown parallel density at plasma-wall interface limited by ion saturation...
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...
The COMPASS tokamak at IPP Prague is a small-size device with an ITER-relevant plasma geometry and operating in both the Ohmic as well neutral beam assisted H-modes since 2012. A basic set of diagnostics installed beginning operation has been gradually broadened type diagnostics, extended number detectors collected channels improved by increased data acquisition speed. In recent years, significant progress diagnostic development motivated performance broadening its scientific programme (L-H...
Abstract It has been shown on several tokamaks that application of a resonant magnetic perturbation (RMP) field to the plasma can lead suppression or mitigation edge-localized mode (ELM) instabilities. Due rotation in RMP reference system, currents are induced surfaces within plasma, consequently screening original perturbation. In this work, extensive set 104 saddle loops installed COMPASS tokamak is utilized measure response for two n = 2 configurations different poloidal m spectra....
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...