M. Peterka
A5066654717- 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
- Plasma Diagnostics and Applications
- Nuclear reactor physics and engineering
- Meteorological Phenomena and Simulations
- Education, Psychology, and Social Research
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- GNSS positioning and interference
- Advanced materials and composites
- High-Energy Particle Collisions Research
- Spacecraft and Cryogenic Technologies
- Dust and Plasma Wave Phenomena
- Metal Alloys Wear and Properties
- Advanced Fiber Laser Technologies
- Distributed systems and fault tolerance
- Anomaly Detection Techniques and Applications
- Advanced Fiber Optic Sensors
- Advanced Data Storage Technologies
- Inertial Sensor and Navigation
- Nuclear Materials and Properties
Czech Academy of Sciences, Institute of Plasma Physics
2016-2025
Charles University
2015-2024
Royal Military Academy
2020
Universität Innsbruck
2011-2012
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,...
This paper presents turbulence investigations in the scrape-off layer (SOL) of ASDEX Upgrade ohmic, L-mode and H-mode discharges using electrostatic electromagnetic probes. Detailed studies are performed on small scale ELM filaments. Simultaneous measurements floating plasma potential fluctuations revealed significant differences between these quantities. Large errors can occur when electric field is extracted from measurements, even ohmic discharges. Turbulence plasmas show existence...
Sustained edge localized mode (ELM) mitigation has been achieved on MAST and AUG using resonant magnetic perturbations (RMPs) with various toroidal numbers over a wide range of low to medium collisionality discharges. The ELM energy loss peak heat loads at the divertor targets have reduced. phase is typically associated drop in plasma density overall stored energy. In one particular scenario MAST, by carefully adjusting fuelling it possible counteract produce plasmas mitigated ELMs, reduced...
The electron temperature and density pedestals tend to vary in their relative radial positions, as observed DIII-D (Beurskens et al 2011 Phys. Plasmas 18 056120) ASDEX Upgrade (Dunne 2017 Plasma Control. Fusion 59 14017). This so-called shift has an impact on the pedestal magnetohydrodynamic (MHD) stability hence height (Osborne 2015 Nucl. 55 063018). present work studies effect of JET ITER-like wall (JET-ILW) baseline low triangularity (δ) unseeded plasmas, similar JET-C discharges. As...
Partial detachment is the desired regime for baseline burning plasma scenario in ITER and next-step devices, as it allows to dissipate majority of energy carried by charged particles through scrape-off-layer (SOL) thus avoids localised heat flux deposition divertor region.The COMPASS tokamak equipped with an open has a relatively short connection length, both factors being unfavourable access detachment.As such, only approach naturally detached operation at very high lineaveraged densities...
A new system of probes was recently installed in the divertor tokamak COMPASS order to investigate ELM energy density with high spatial and temporal resolution. The consists two arrays rooftop-shaped Langmuir (LPs) used measure floating potential or ion saturation current one array Ball-pen (BPPs) plasma a resolution ~3.5 mm. combination BPPs LPs yields electron temperature microsecond We report on design probe first results profile measurements ELMy H-mode L-mode. also present comparative...
Three dimensionless scans in the normalized Larmor radius ρ*, collisionality ν* and plasma pressure β have been performed JET with ITER-like wall (JET-ILW).
Abstract To achieve their goals, future thermonuclear reactors such as ITER and DEMO are expected to operate plasmas with a high magnetic field, triangularity confinement. address the corresponding challenges, concept of high-field ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>B</mml:mi> <mml:mtext>T</mml:mtext> </mml:mrow> </mml:msub> <mml:mtext>⩽</mml:mtext> </mml:math> 5 T), high-current <mml:mi>I</mml:mi>...
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...
Abstract Experimental investigations of the plasma potential, poloidal electric field and electron temperature during L‐mode ELMy H‐mode were performed on ASDEX Upgrade by means a probe head containing four ball‐pen probes Langmuir probes. This allows to measure simultaneously floating potential at same time which are related temperature. Thus combination offers possibility determine directly with high temporal resolution. novel measurement method is compared standard techniques. The...
Abstract The reduction of the incident heat flux onto divertor will be a necessity for future thermonuclear reactors. Impurity seeding is recognized as an efficient way to achieve partial detachment regime, which allows dissipate large fraction power by radiation. This paper presents real-time feedback system (RTFS) based on impurity controlled combined ball-pen and Langmuir probe array in COMPASS tokamak. A number features have been studied, such type impurity, location, constants used...
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...
A new technique for fitting the full radial profiles of electron density and temperature obtained by Thomson scattering diagnostic in H-mode discharges on COMPASS tokamak is described. The combines conventionally used modified hyperbolic tangent function edge transport barrier (pedestal) a modification Gaussian core plasma. Low number parameters this combined their straightforward interpretability controllability provide robust method obtaining physically reasonable profile fits....
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....
Resonant magnetic perturbations (RMPs) used to control type-I edge-localized modes produce a splitting of the peaks heat flux profile on divertor. The additional can appear outside areas connected plasma core by perturbed field lines due perpendicular transport. This effect has been studied so far using demanding three-dimensional transport simulations. We present simple method quantitatively estimate that RMP will needs only line tracing determine so-called tangle distance function, and...
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 The ball‐pen probe is an innovative electric for direct measurements of plasma potential in magnetised hot plasma. This based on the Katsumata concept. can adjust ratio I − sat + electron and ion saturation currents to be equal one causing characteristics become symmetric. If this achieved, floating potential. We show application a two low‐temperature devices torsatron TJ‐K (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)