S. Zoletnik

8585952300

Publications - 20

Atomic Beam Probe Synthetic Diagnostic in the COMPASS Tokamak and Its Application in Fusion Plasmas

M. Berta P. Hacek D. Réfy M. Aradi G. I. Pokol J. Krbec O. Asztalos Shimpei Futatani S. Zoletnik

Publication Name: Fusion Science and Technology

Publication Date: 2025-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The atomic beam probe (ABP) is a beam diagnostic concept that opens opportunities in plasma edge measurements due to the sensitivity of the magnetic field and the high temporal resolution. The first ABP has been installed and is operating on the COMPASS tokamak. A new numerical toolset, which is the subject of this paper, was required to model the diagnostic to accurately detect the alkali beam. For further development and understanding of the diagnostic, this tool had to be designed to simulate different magnetic field configurations in a performance-efficient manner. The TAIGA synthetic diagnostic (TAIGA-SD), which was implemented with a massively parallel trajectory solver core that runs on graphic cards to support experiments, provides a better understanding of measurements and has opened opportunities for future applications. This paper presents the model concept with relevant physical processes and necessary simplifications. The submodules implemented or integrated into the synthetic diagnostic are explained and described, and their scopes of validity are highlighted. This includes the integration of RENATE-OD for the primary ionization radial distribution for lithium beams, as well as the implementation and verification of a combined electron impact and charge exchange ionization module for other alkaline beams, which is a new atomic physics solver. Calculations were performed to investigate the relation between magnetic field, electron density, and temperature perturbations. Further simulations were run to estimate beam attenuation due to secondary ionization. The utilization of the ABP synthetic diagnostic is demonstrated by comparing it with the measurements.

Open Access: Yes

DOI: 10.1080/15361055.2025.2511540

Plasma edge current fluctuation measurements during the ELM cycle with the atomic beam probe at COMPASS

M. Berta G. Anda D. Dunai P. Hacek D. Réfy M. Aradi J. Krbec S. Zoletnik A. Bencze

Publication Name: 46th Eps Conference on Plasma Physics Eps 2019

Publication Date: 2019-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

No description provided

Open Access: Yes

DOI: DOI not available

Development of an ion beam detector for the atomic beam probe diagnostic

M. Berta G. Anda D. Dunai P. Hacek D. Réfy M. Aradi J. Krbec R. Pánek S. Zoletnik A. Bencze V. Weinzettl J. Stockel

Publication Name: Review of Scientific Instruments

Publication Date: 2018-11-01

Volume: 89

Issue: 11

Page Range: Unknown

Description:

The atomic beam probe diagnostic concept aims at measuring the edge magnetic field and through that edge current distribution in fusion plasmas by observing trajectories of an ion beam stemming from a diagnostic neutral beam. The diagnostic potentially has microsecond scale time resolution and can thus prove to be a powerful option to study fast changes in the edge plasma. A test detector has been installed on the COMPASS tokamak as an extension of the existing lithium beam diagnostic system. It employs a relatively simple concept of an array of conductive detection plates measuring the incident ion current, which is then amplified and converted to a voltage signal. The aim of the test detector is to experimentally examine the idea of the diagnostic and provide background data for design and installation of a final detector. Also, a numerical code based on the CUDA parallel computing platform has been developed for modeling lithium ion trajectories in the given COMPASS plasma discharges. We present the developments of the detector design and test measurements of the diagnostic performed both in a laboratory beam system and on the COMPASS tokamak.

Open Access: Yes

DOI: 10.1063/1.5044529

Advanced neutral alkali beam diagnostics for applications in fusion research (invited)

D. Réfy B. Tál G. Petravich G. I. Pokol M. Vécsei G. Anda D. Dunai M. Aradi O. Asztalos S. Bató G. Demeter S. Hegedus P. Hacek M. Berta A. Bencze T. Krizsanóczi M. Lampert G. H. Hu D. Nagy J. Németh M. Otte S. Zoletnik

Publication Name: Review of Scientific Instruments

Publication Date: 2018-10-01

Volume: 89

Issue: 10

Page Range: Unknown

Description:

Diagnosing the density profile at the edge of high temperature fusion plasmas by an accelerated lithium beam is a known technique since decades. By knowledge of the relevant atomic physics rate coefficients, the plasma electron density profile can be calculated from the relatively calibrated light profile along the beam. Several additional possibilities have already been demonstrated: Charge Exchange Resonance Spectroscopy (CXRS) for ion temperature/flow and Zeeman polarimetry for edge plasma current; therefore the Li-beam diagnostic offers a wealth of information at the plasma edge. The weaknesses of the method are the relatively faint light signal, background light, and technical difficulties of the beam injector which usually seriously limit the applicability. In this talk, we present systematic developments in alkali-beam diagnostics (Li, Na) for the injector and the observation system and detectors which resulted in strongly increased capabilities. Advanced systems have been built, and microsecond scale density profile, turbulence, and zonal flow measurement have been demonstrated. A novel edge current measurement technique has also been designed, and components have been tested with potential microsecond-scale time resolution. Additional possibilities of these advanced systems for spectral measurements (CXRS and various Zeeman schemes) are also discussed.

Open Access: Yes

DOI: 10.1063/1.5039309

Atomic Beam Probe diagnostic for plasma edge current measurements at COMPASS

M. Berta G. Anda D. Dunai P. Hacek D. Réfy M. Aradi M. Lampert J. Krbec M. Palánkai S. Hegedus B. Leskó J. Kádi D. Nagy R. Pánek S. Zoletnik A. Bencze V. Weinzettl

Publication Name: 45th Eps Conference on Plasma Physics Eps 2018

Publication Date: 2018-01-01

Volume: 2018-July

Issue: Unknown

Page Range: 1028-1031

Description:

No description provided

Open Access: Yes

DOI: DOI not available

Progress in diagnostics of the COMPASS tokamak

P. Bilkova P. Bohm O. Bogár E. Gauthier K. Kovarik J. P. Gunn D. I. Naydenkova A. Podolnik D. Réfy N. Vianello J. Adámek J. Horacek O. Grover R. Dejarnac J. Cavalier O. Ficker M. Hron M. Komm E. Matveeva R. Pánek M. Peterka J. Seidl M. Dimitrova D. Fridrich A. Devitre T. Markovic G. Anda D. Dunai M. Rabinski J. Stockel J. Mlynar R. Paprok K. Mitošinková M. Sos J. Varju M. Tomes M. Varavin P. Hacek J. Krbec R. Gomes M. Berta J. Havlicek A. Havranek T. Krizsanóczi V. Weinzettl P. Vondráček F. Zacek M. Vlainic M. Stano T. Pereira G. P. Ermak J. Zebrowski M. Jakubowski K. Malinowski M. Spolaore J. Zajac A. Silva S. Zoletnik Tsv Popov D. Sarychev M. Imrišek S. Nanobashvili

Publication Name: Journal of Instrumentation

Publication Date: 2017-12-07

Volume: 12

Issue: 12

Page Range: Unknown

Description:

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 as neutral beam assisted H-modes since 2012. A basic set of diagnostics installed at the beginning of the COMPASS operation has been gradually broadened in type of diagnostics, extended in number of detectors and collected channels and improved by an increased data acquisition speed. In recent years, a significant progress in diagnostic development has been motivated by the improved COMPASS plasma performance and broadening of its scientific programme (L-H transition and pedestal scaling studies, magnetic perturbations, runaway electron control and mitigation, plasma-surface interaction and corresponding heat fluxes, Alfvenic and edge localized mode observations, disruptions, etc.). In this contribution, we describe major upgrades of a broad spectrum of the COMPASS diagnostics and discuss their potential for physical studies. In particular, scrape-off layer plasma diagnostics will be represented by a new concept for microsecond electron temperature and heat flux measurements - we introduce a new set of divertor Langmuir and ball-pen probe arrays, newly constructed probe heads for reciprocating manipulators as well as several types of standalone probes. Among optical tools, an upgraded high-resolution edge Thomson scattering diagnostic for pedestal studies and a set of new visible light and infrared (plasma-surface interaction investigations) cameras will be described. Particle and beam diagnostics will be covered by a neutral particle analyzer, diagnostics on a lithium beam, Cherenkov detectors (for a direct detection of runaway electrons) and neutron detectors. We also present new modifications of the microwave reflectometer for fast edge density profile measurements.

Open Access: Yes

DOI: 10.1088/1748-0221/12/12/C12015

Lithium beam diagnostic system on the COMPASS tokamak

M. Berta G. Anda S. Bató D. Dunai T. Krizsanóczi T. Ilkei P. Hacek D. Réfy J. Krbec I. G. Kiss G. Veres S. Zoletnik A. Bencze

Publication Name: Fusion Engineering and Design

Publication Date: 2016-10-01

Volume: 108

Issue: Unknown

Page Range: 1-6

Description:

An improved lithium beam based beam emission spectroscopy system - installed on COMPASS tokamak - is described. The beam energy enhanced up to 120 keV for Atomic Beam Probe measurement. The size of the ion source is doubled, using a newly developed thermionic heater instead of the conventionally used heating (tungsten or molybdenum) filament. The neutralizer is also improved. It produces the same sodium vapor in a cell but minimize the loss condensing the vapor on a cold surface which is led back (in fluid state) into the sodium oven. This way we call it recirculating neutralizer. The observation system consists of a CCD camera and an avalanche photodiode array.

Open Access: Yes

DOI: 10.1016/j.fusengdes.2016.04.022

Li-BES detection system for plasma turbulence measurements on the COMPASS tokamak

M. Berta G. Anda D. Dunai P. Hacek D. Réfy A. Kovácsik J. Krbec M. Hron G. Veres R. Pánek S. Zoletnik A. Bencze V. Weinzettl

Publication Name: Fusion Engineering and Design

Publication Date: 2015-10-01

Volume: 96-97

Issue: Unknown

Page Range: 795-798

Description:

A new Li beam emission spectroscopy (Li-BES) diagnostic system with a ∼ cm spatial resolution, and with beam energy ranging from 10 keV up to 120 keV and a 18 channel Avalanche photo diode (APD) detector system sampled at 2 MHz has been recently installed and tested on the COMPASS tokamak. This diagnostic allows to reconstruct density profile based on directly measured light profiles, and to follow turbulent behaviour of the edge plasma. The paper reports technical capabilities of this new system designed for fine spatio-temporal measurements of plasma electron density. Focusing on turbulence-induced fluctuation measurements, we demonstrate how physically relevant information can be extracted using the COMPASS Li-BES system.

Open Access: Yes

DOI: 10.1016/j.fusengdes.2015.06.030

Development of atomic beam probe for tokamaks

M. Berta G. Anda I. G. Kiss J. Havlicek S. Tulipán P. Hacek M. Aradi Cs Buday G. Veres S. Zoletnik A. Bencze

Publication Name: Fusion Engineering and Design

Publication Date: 2013-11-01

Volume: 88

Issue: 11

Page Range: 2875-2880

Description:

The concept and development of a new detection method for light alkali ions stemming from diagnostic beams installed on medium size tokamak is described. The method allows us the simultaneous measurement of plasma density fluctuations and fast variations in poloidal magnetic field, therefore one can infer the fast changes in edge plasma current. The concept has been worked out and the whole design process has been done at Wigner RCP. The test detector with appropriate mechanics and electronics is already installed on COMPASS tokamak. General ion trajectory calculation code (ABPIons) has also been developed. Detailed calculations show the possibility of reconstruction of edge plasma current density profile changes with high temporal resolution, and the possibility of density profile reconstruction with better spatial resolution compared to standard Li-BES measurement, this is important for pedestal studies. © 2013 Elsevier B.V.

Open Access: Yes

DOI: 10.1016/j.fusengdes.2013.05.064

Overview of the COMPASS diagnostics

P. Bilkova P. Bohm D. I. Naydenkova J. Adámek J. Horacek R. Dejarnac M. Hron R. Pánek I. Ďuran G. Anda J. Stockel J. Mlynar D. Sestak M. Aftanas G. Veres F. Janky J. Brotankova R. Melich P. Hacek R. Gomes M. Berta J. Havlicek V. Weinzettl F. Zacek A. Szappanos J. Zajac D. Jares J. Ghosh V. F. Shevchenko R. Scannell M. Walsh H. W. Müller V. Igochine A. Silva M. Manso S. Zoletnik Tsv Popov D. Sarychev V. K. Kiselov S. Nanobashvili

Publication Name: Fusion Engineering and Design

Publication Date: 2011-10-01

Volume: 86

Issue: 6-8

Page Range: 1227-1231

Description:

The COMPASS tokamak, a divertor device with clear H-mode and ITER-relevant geometry, has been re-installed in IPP Prague after its transport from CCFE in UK. The first plasma was achieved in December 2008. Many new diagnostic tools with both high temporal and spatial resolutions have been developed to address the scientific programme of COMPASS focused on H-mode physics and pedestal investigations. In the paper, an overview of existing and in near future planned diagnostics (magnetic, spectroscopy, microwave, probe and beam/particle) on COMPASS is given including their basic technical specifications and achievements. © 2011 EURATOM. Published by Elsevier B.V. All rights reserved.

Open Access: Yes

DOI: 10.1016/j.fusengdes.2010.12.024

EDICAM fast video diagnostic installation on the COMPASS tokamak

M. Berta S. Tulipán A. Szappanos M. Hron G. Veres R. Pánek S. Zoletnik V. Weinzettl J. Stockel

Publication Name: Fusion Engineering and Design

Publication Date: 2010-01-01

Volume: 85

Issue: 3-4

Page Range: 370-373

Description:

A new camera system event detection intelligent camera (EDICAM) is being developed by the Hungarian Association and has been installed on the COMPASS tokamak in the Institute of Plasma Physics AS CR in Prague, during February 2009. The standalone system contains a data acquisition PC and a prototype sensor module of EDICAM. Appropriate optical system have been designed and adjusted for the local requirements, and a mechanical holder keeps the camera out of the magnetic field. The fast camera contains a monochrome CMOS sensor with advanced control features and spectral sensitivity in the visible range. A special web based control interface has been implemented using Java spring framework to provide the control features in a graphical user environment. Java native interface (JNI) is used to reach the driver functions and to collect the data stored by direct memory access (DMA). Using a built in real-time streaming server one can see the live video from the camera through any web browser in the intranet. The live video is distributed in a Motion Jpeg format using real-time streaming protocol (RTSP) and a Java applet have been written to show the movie on the client side. The control system contains basic image processing features and the 3D wireframe of the tokamak can be projected to the selected frames. A MatLab interface is also presented with advanced post processing and analysis features to make the raw data available for high level computing programs. In this contribution all the concepts of EDICAM control center and the functions of the distinct software modules are described. © 2009 Elsevier B.V. All rights reserved.

Open Access: Yes

DOI: 10.1016/j.fusengdes.2009.11.001

Concept of an atomic beam probe diagnostic on COMPASS tokamak

M. Berta G. Anda D. Dunai M. Aradi G. Veres S. Zoletnik A. Bencze

Publication Name: 36th Eps Conference on Plasma Physics 2009 Eps 2009 Europhysics Conference Abstracts

Publication Date: 2009-12-01

Volume: 33 E2

Issue: Unknown

Page Range: 1399-1402

Description:

No description provided

Open Access: Yes

DOI: DOI not available

Results of Joint Experiments and other IAEA activities on research using small tokamaks

N. Kirneva V. Vershkov M. Sokolov C. Silva D. Valcrcel R. Gonzales A. Fonseca B. Kuteev L. Petrov M. Kolokoltsov J. Herrera M. Nieto-Perez A. Czarnecka A. Talebitaher A. Melnikov P. Khorshid V. Soldatov C. R. Gutierrez Tapia R. Dejarnac P. Balan M. Hron H. Fernandes I. Ďuran D. Dunai J. Stockel J. Brotankova L. A. Berni E. Del Bosco J. Sentkerestiova M. Gryaznevich G. Van Oost E. Dufkova P. Peleman A. Sharnin V. Pavlov J. Ferreira R. Gomes M. Berta V. Weinzettl A. Malaquias B. Tl J. Zajac G. Mank F. J.R. Simes I. El Chama Neto H. Figueiredo N. Dreval D. Nurov A. W. Kraemer-Flecken B. Brotas P. Carvalho S. Zoletnik Y. Kuznetsov L. Ruchko H. Hegazy A. Ovsyannikov R. Coelho A. Duarte J. Santos H. Hegazy G. M. Vorobjev E. Sukhov A. Singh G. Kirnev V. Budaev J. Figueiredo G. Ramos L. I. Krupnik I. Nedzelski A. Neto

Publication Name: Nuclear Fusion

Publication Date: 2009-09-21

Volume: 49

Issue: 10

Page Range: Unknown

Description:

This paper presents an overview of the results obtained during the Joint Experiments organized in the framework of the IAEA Coordinated Research Project on 'Joint Research Using Small Tokamaks' that have been carried out on the tokamaks CASTOR at IPP Prague, Czech Republic (2005), T-10 at RRC 'Kurchatov Institute', Moscow, Russia (2006), and the most recent one at ISTTOK at IST, Lisbon, Portugal, in 2007. Experimental programmes were aimed at diagnosing and characterizing the core and the edge plasma turbulence in a tokamak in order to investigate correlations between the occurrence of transport barriers, improved confinement, electric fields and electrostatic turbulence using advanced diagnostics with high spatial and temporal resolution. On CASTOR and ISTTOK, electric fields were generated by biasing an electrode inserted into the edge plasma and an improvement of the global particle confinement induced by the electrode positive biasing has been observed. Geodesic acoustic modes were studied using heavy ion beam diagnostics on T-10 and ISTTOK and correlation reflectometry on T-10. ISTTOK is equipped with a gallium jet injector and the technical feasibility of gallium jets interacting with plasmas has been investigated in pulsed and ac operation. The first Joint Experiments have clearly demonstrated that small tokamaks are suitable for broad international cooperation to conduct dedicated joint research programmes. Other activities within the IAEA Coordinated Research Project on Joint Research Using Small Tokamaks are also overviewed. © 2009 IAEA, Vienna.

Open Access: Yes

DOI: 10.1088/0029-5515/49/10/104026

Joint experiments on the Tokamaks CASTOR and Ta10

E. Dufkova J. Brotankova M. Berta R. Dejarnac A. Fonseca G. M. Vorobjev A. Talebitaher J. Sentkerestiova B. Tál R. Gonzales V. Soldatov E. Sukhov I. Ďuran I. El Chama Neto C. R.Gutierrez Tapia A. W. Kraemeraflecken J. Ferreira A. Singh H. Hegazy H. Hegazy P. Khorshid L. Ruchko G. Kirnev N. Kirneva E. Del Bosco V. Vershkov A. Malaquias M. Hron B. Kuteev G. Mank M. Gryaznevich L. I. Krupnik V. Budaev A. Ovsyannikov A. Melnikov G. Van Oost M. Sokolov Y. Kuznetsov P. Peleman J. Zajac S. Zoletnik V. Weinzettl J. Stockel

Publication Name: Aip Conference Proceedings

Publication Date: 2008-12-01

Volume: 996

Issue: Unknown

Page Range: 24-33

Description:

Small tokamaks may significantly contribute to the better understanding of phenomena in a wide range of fields such as plasma confiement and energy transport; plasma stability in different magnetic configurations; plasma turbulence and its impact on local and global plasma parameters; processes at the plasma edge and plasmaawall interaction; scenarios of additional heating and nonainductive current drive; new methods of plasma profile and parameter control; development of novel plasma diagnostics; benchmarking of new numerical codes and so on. Furthermore, due to the compactness, flexibility, low operation costs and high skill of their personnel small tokamaks are very convenient to develop and test new materials and technologies. Small tokamaks are suitable and important for broad international cooperation, providing the necessary environment and manpower to conduct dedicated joint research programmes. In addition, the experimental work on small tokamaks is very appropriate for the education of students, scientific activities of postagraduate students and for the training of personnel for large tokamaks. The first Joint (Host Laboratory) Experiment (JE1) has been carried out in 2005 on the CASTOR tokamak at the IPP Prague, Czech Republic. It was jointly organized by the IPPaASCR and KFKI HAC, Budapest, involved 20 scientists from 7 countries and was supported through the IAEA and the ICTP, Trieste. The objective of JE1 was to perform studies of plasma edge turbulence and plasma confinement. Following the success of JE1, JE2 has been performed on Ta10 at RRC "Kurchatov Institute" in Moscow; 30 scientists from 13 countries participated in this experiment. This experiment aimed to continue JE1 turbulence studies, now extending them to the plasma core. Results of JE1 and JE2 will be overviewed and compared. © 2008 American Institute of Physics.

Open Access: Yes

DOI: 10.1063/1.2917019

Joint experiments on small tokamaks: Edge plasma studies on CASTOR

E. Dufkova J. Brotankova M. Berta R. Dejarnac A. Fonseca A. Talebitaher J. Sentkerestiova B. Tál J. Horacek J. Ferrera A. Ossyannikov M. Sokholov I. Ďuran A. Singh H. Hegazy H. Hegazy E. Del Bosco A. Malaquias M. Hron G. Mank M. Gryaznevich G. Van Oost Y. Kuznetsov P. Peleman S. Zoletnik V. Weinzettl J. Stockel

Publication Name: Nuclear Fusion

Publication Date: 2007-12-01

Volume: 47

Issue: 5

Page Range: 378-386

Description:

The 1st Joint (Host Laboratory) Experiment on 'joint research using small tokamaks' was carried out using the IPP Prague experimental facility 'CASTOR tokamak'. The main experimental programme was aimed at characterizing the edge plasma in a tokamak by using different advanced diagnostic techniques. It is widely recognized that characterization of phenomena occurring at the plasma edge is essential for understanding the plasma confinement in a tokamak. The edge plasma in small and large scale experiments has many similar features, and the results obtained through detailed measurements in a small flexible device such as CASTOR are in many aspects still relevant to those in large tokamaks. Therefore, it is expected that the results of this joint experiment will have general validity. The radial and poloidal structure of electrostatic turbulence was characterized. The effects of edge biasing were analysed. Radiation fluctuations and profile measurements were performed using fast bolometry. Plasma position measurements were performed using novel Hall sensors. © 2007 IAEA, Vienna.

Open Access: Yes

DOI: 10.1088/0029-5515/47/5/002

Progress on joint experiments on small tokamaks

E. Dufkova J. Brotankova M. Berta R. Dejarnac A. Fonseca G. Ramos G. M. Vorobjev A. Talebitaher J. Sentkerestiova B. Tál I. El Chama Neto V. Soldatov E. Sukhov I. Ďuran A. W. Kraemer-Flecken J. Ferreira A. Singh H. Hegazy H. Hegazy A. M. Marques Fonseca P. Khorshid C. R. Gutierrez Tapia L. Ruchko G. Kirnev N. Kirneva E. Del Bosco V. Vershkov A. Malaquias M. Hron B. Kuteev G. Mank M. Gryaznevich L. I. Krupnik V. Budaev A. Ovsyannikov A. Melnikov G. Van Oost M. Sokolov Y. Kuznetsov P. Peleman J. Zajac S. Zoletnik V. Weinzettl J. Stockel

Publication Name: 34th Eps Conference on Plasma Physics 2007 Eps 2007 Europhysics Conference Abstracts

Publication Date: 2007-12-01

Volume: 31

Issue: 1

Page Range: 435-438

Description:

No description provided

Open Access: Yes

DOI: DOI not available

The spatial structure of flows, Reynolds stress and turbulence in the CASTOR tokamak

M. Berta R. Dejarnac B. Tál M. Hron J. Zajac S. Zoletnik A. Bencze J. Stockel

Publication Name: 33rd Eps Conference on Plasma Physics 2006 Eps 2006

Publication Date: 2006-12-01

Volume: 2

Issue: Unknown

Page Range: 1452-1455

Description:

No description provided

Open Access: Yes

DOI: DOI not available

Observation of zonal flow-like structures using the autocorrelation-width technique

M. Berta J. Adámek M. Hron S. Zoletnik A. Bencze J. Stockel

Publication Name: Plasma Physics and Controlled Fusion

Publication Date: 2006-04-01

Volume: 48

Issue: 4

Page Range: S137-S153

Description:

This paper presents the first application of the autocorrelation-width technique (Bencze A and Zoletnik S 2005 Phys. Plasmas 12 052323) to detect and characterize the microturbulence-zonal flow system using fluctuating signals ( , ) measured by arrays of single-tip Langmuir probes in the CASTOR tokamak. Radially localized (≈1 cm) random flow structures have been clearly observed with a lifetime of ≈1 ms and a long-range poloidal correlation, extending over at least one-fourth of the poloidal circumference. © 2006 IOP Publishing Ltd.

Open Access: Yes

DOI: 10.1088/0741-3335/48/4/S10

Detection of radially localized and poloidally symmetric structures in the poloidal flow of tokamak plasmas

M. Berta J. Adámek M. Hron S. Zoletnik A. Bencze J. Stockel

Publication Name: 32nd Eps Conference on Plasma Physics 2005 Eps 2005 Held with the 8th International Workshop on Fast Ignition of Fusion Targets Europhysics Conference Abstracts

Publication Date: 2005-12-01

Volume: 3

Issue: Unknown

Page Range: 1994-1997

Description:

No description provided

Open Access: Yes

DOI: DOI not available

Two-dimensional density and density fluctuation diagnostic for the edge plasma in fusion devices

M. Berta S. Fiedler G. Petravich J. Schweinzer K. McCormick S. Zoletnik A. Bencze

Publication Name: Review of Scientific Instruments

Publication Date: 2005-07-01

Volume: 76

Issue: 7

Page Range: Unknown

Description:

A technique is described for the two-dimensional measurement of electron density profile and fluctuations in edge regions of magnetically confined fusion plasmas. The method is based on existing lithium beam beam emission spectroscopy technique, two-dimensional resolution is achieved by electrostatically scanning the beam. If scanning is performed faster than the lifetime of the turbulent structures in the plasma, the diagnostic is capable of measuring the structure of electron density fluctuations as well. The beam strength of currently available beams makes the detection of single fluctuation events impossible, but the full two-dimensional spatial structure of correlations can still be determined. The article describes the technique and fast beam deflection tests up to 250 kHz. The capabilities of such a diagnostic for fluctuation measurement are explored by simulating measurement signals. Measurement of both the two-dimensional density profile, fluctuation correlation function and poloidal flow velocity are demonstrated at the Wendelstein 7-AS stellarator. The shape of the density profile, the radial and poloidal correlation lengths and the flow velocity are in agreement with expectations and previous Langmuir probe measurement. © 2005 American Institute of Physics.

Open Access: Yes

DOI: 10.1063/1.1947727