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2. Nonlinear dynamics of energetic-particle driven geodesic acoustic modes in ASDEX Upgrade

Author

Novikau, I., Biancalani, A., Bottino, A., Lauber, Ph., Poli, E., Manz, P., Conway, G. D., Di Siena, A., Ohana, N., Lanti, E., Villard, L., Team, ASDEX Upgrade, and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Tokamak, Population, FOS: Physical sciences, Electron, Kinetic energy, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, law.invention, ASDEX Upgrade, law, Physics::Plasma Physics, 0103 physical sciences, 010306 general physics, education, Physics, education.field_of_study, Plasma, Condensed Matter Physics, simulation, Physics - Plasma Physics, Computational physics, Magnetic field, Plasma Physics (physics.plasm-ph), code, Transport phenomena, explanation
Abstract

Turbulence in tokamaks generates radially sheared zonal flows. Their oscillatory counterparts, geodesic acoustic modes (GAMs), appear due to the action of the magnetic field curvature. The GAMs can be driven unstable by an anisotropic energetic particle (EP) population leading to the formation of global radial structures, called energetic-particle-driven geodesic acoustic modes (EGAMs). The EGAMs can redistribute EP energy to the bulk plasma through collisionless wave-particle interaction. In such a way, the EGAMs might contribute to the plasma heating. Thus, investigation of EGAM properties, especially in the velocity space, is necessary for precise understanding of the transport phenomena in tokamak plasmas. In this work, the nonlinear dynamics of EGAMs without considering the mode interaction with the turbulence is investigated with the help of a Mode-Particle-Resonance (MPR) diagnostic implemented in the global gyrokinetic particle-in-cell code ORB5. An ASDEX Upgrade discharge is chosen as a reference case for this investigation due to its rich EP nonlinear dynamics. An experimentally relevant magnetic field configuration, thermal species profiles, and an EP density profile are taken for EGAM chirping modeling and its comparison with available empirical data. The same magnetic configuration is used to explore energy transfer by the mode from the energetic particles to the thermal plasma including kinetic electron effects. For a given EGAM level, the plasma heating by the mode can be significantly enhanced by varying the EP parameters. Electron dynamics decreases the EGAM saturation amplitude and consequently reduces the plasma heating, even though the mode transfers its energy to thermal ions much more than to electrons.

Published
2020
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3. Linear gyrokinetic investigation of the geodesic acoustic modes in realistic tokamak configurations

Author

Novikau, I., Biancalani, A., Bottino, A., Conway, G. D., Gürcan, Özgür, Manz, P., Morel, Pierre, Poli, E., Siena, A. Di, Team, ASDEX Upgrade, ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Dipartimento di Fisica Università di Torino and INFN (DF_TORINO), Dipartimento di Fisica infi & Università di Torino, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
Physics, Safety factor, Tokamak, Geodesic, FOS: Physical sciences, Electron, Condensed Matter Physics, 01 natural sciences, 7. Clean energy, Physics - Plasma Physics, 010305 fluids & plasmas, Computational physics, law.invention, Plasma Physics (physics.plasm-ph), Temperature gradient, ASDEX Upgrade, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Physics::Plasma Physics, law, Beta (plasma physics), 0103 physical sciences, Wavenumber, 010306 general physics
Abstract

International audience; In order to provide scaling formulae for the geodesic acoustic mode (GAM) frequency and damping rate, GAMs are studied by means of the gyrokinetic global particle-in-cell code ORB5. Linear electromagnetic simulations in the low-βe limit have been performed in order to separate acoustic and Alfvnic time scales and obtain more accurate measurements. The dependence of the frequency and damping rate on several parameters such as the safety factor, the GAM radial wavenumber, and the plasma elongation is studied. All simulations have been performed with kinetic electrons with a realistic electron/ion mass ratio. Interpolating formulae for the GAM frequency and damping rate, based on the results of the gyrokinetic simulations, have been derived. Using these expressions, the influence of the temperature gradient on the damping rate is also investigated. Finally, the results are applied to the study of a real discharge of the ASDEX Upgrade tokamak.

Published
2017

4. Turbulence intermittency linked to the weakly coherent mode in ASDEX Upgrade I-mode plasmas

Author

Happel, T., Manz, P., Ryter, F., Hennequin, Pascale, Hetzenecker, A., Conway, G. D., Luis Guimarais, Honoré, Cyrille, Stroth, U., Viezzer, E., The Asdex Upgrade, Team, Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, Nuclear and High Energy Physics, Tokamak, Turbulence, Mode (statistics), Plasma, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, law.invention, Temperature gradient, Amplitude, ASDEX Upgrade, law, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Intermittency, 0103 physical sciences, Atomic physics, 010306 general physics
Abstract

This letter shows for the first time a pronounced increase of extremely intermittent edge density turbulence behavior inside the confinement region related to the I-mode confinement regime in the ASDEX Upgrade tokamak. With improving confinement, the perpendicular propagation velocity of density fluctuations in the plasma edge increases together with the intermittency of the observed density bursts. Furthermore, it is shown that the weakly coherent mode, a fluctuation feature generally observed in I-mode plasmas, is connected to the observed bursts. It is suggested that the large amplitude density bursts could be generated by a non-linearity similar to that in the Korteweg–de-Vries equation which includes the radial temperature gradient.

Published
2016

5. L-H transition physics in hydrogen and deuterium: key role of the edge radial electric field and ion heat flux

Author

Asdex Upgrade Team T., Ryter F., Cavedon M., Happel T., McDermott R. M., Viezzer E., Conway G. D., Fischer R., Kurzan B., Putterich T., Tardini G., Willensdorfer M., ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, Asdex Upgrade Team, T, Ryter, F, Cavedon, M, Happel, T, Mcdermott, R, Viezzer, E, Conway, G, Fischer, R, Kurzan, B, Putterich, T, Tardini, G, and Willensdorfer, M

Subjects
Physics, Tokamak, ion heat flux, Hydrogen, Plasma parameters, radial electric field, chemistry.chemical_element, Plasma, Condensed Matter Physics, L-H transition, 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, Ion, law.invention, Nuclear Energy and Engineering, ASDEX Upgrade, chemistry, Deuterium, Heat flux, Physics::Plasma Physics, law, 0103 physical sciences, Atomic physics, 010306 general physics
Abstract

Previous work carried out in the ASDEX Upgrade tokamak on the role of the edge radial electric field and ion heat flux in the L-H transition physics in deuterium plasmas has been extended in hydrogen plasmas. Similar discharges were performed in the two gases providing a detailed comparison of the edge kinetic profiles and heat fluxes in L-mode up to the L-H transition, as the heating power is increased. At the L-H transition, the edge ion heat flux just inside the separatrix is about two times higher in hydrogen than in deuterium. However, the ion plasma parameters at the plasma edge, T i and , as well as the radial electric field well, are found to be very similar in the two gases. The transport analysis based on this data reveals that, at the L-H transition, the ion heat transport at the plasma edge is about two times higher in hydrogen than in deuterium, in agreement with the well-known isotope effect of confinement and transport. This indicates that the higher power threshold in hydrogen is mainly due to the higher ion heat transport in this gas.

Published
2016
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6. Density profile and turbulence evolution during L-H transition studied with the ultra-fast swept reflectometer on ASDEX Upgrade

Author

Medvedeva, A., Bottereau, C., Clairet, F., Hennequin, Pascale, Stroth, U., Birkenmeier, G., Cavedon, M., Conway, G D, Happel, T., Heuraux, S., Molina, D., Silva, A., Willensdorfer, M., Team, Asdex Upgrade, ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Physik Department [Garching], Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Instituto de Plasmas e Fusão Nuclear [Lisboa] (IPFN), Instituto Superior Técnico, Universidade Técnica de Lisboa (IST), European Project: 633053,H2020,EURATOM-Adhoc-2014-20,EUROfusion(2014), Medvedeva, A, Bottereau, C, Clairet, F, Hennequin, P, Stroth, U, Birkenmeier, G, Cavedon, M, Conway, G, Happel, T, Heuraux, S, Molina, D, Silva, A, Willensdorfer, M, Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), and Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Tokamak, Electron, 01 natural sciences, 010305 fluids & plasmas, law.invention, I-phase, ASDEX Upgrade, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], law, Electric field, 0103 physical sciences, plasma physic, 010306 general physics, tokamak, nuclear fusion, Pressure gradient, Physics, reflectometry, Turbulence, turbulence, Plasma, Condensed Matter Physics, L-H transition, Computational physics, Nuclear Energy and Engineering, Temporal resolution
Abstract

International audience; The ultra-fast swept reflectometer with the sweep time of 1 ? s, inferior to the characteristic turbulent time scale, has provided the measurements of the fast density and density fluctuation evolution across major parts of tokamak plasma radius. The L-H transitions in a series of plasma discharges in ASDEX Upgrade have been studied with a high temporal resolution. The comparison of the density fluctuation behaviour in L- and H-mode is presented. The I-phase oscillation dynamics has been described in terms of the density fluctuation level, the radial electric field and the normalised electron pressure gradient. Indications for a phase shift between the turbulence and the radial electric field are observed in the beginning of the I-phase, where the turbulence grows first and the radial electric field increase follows. In the established I-phase the electric field and the turbulence are in phase.

Published
2017

7. Turbulence characteristics of the I-mode confinement regime in ASDEX Upgrade

Author

Manz, P., Happel, T., Ryter, F., Bernert, M., Birkenmeier, G., Conway, G. D., Dunne, M., Guimarais, L., Hennequin, Pascale, Hetzenecker, A., Honoré, Cyrille, Lauber, P., Maraschek, M., Nikolaeva, V., Prisiazhniuk, D., Stroth, U., Viezzer, E., The ASDEX Upgrade, Team2, Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, European Union (UE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, Nuclear and High Energy Physics, Turbulence, I-mode, Mode (statistics), Magnetic confinement fusion, Plasma, Wavelets, Condensed Matter Physics, 01 natural sciences, GAM, 010305 fluids & plasmas, Computational physics, Nonlinear system, Coupling (physics), Modulational instability, ASDEX Upgrade, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Physics::Plasma Physics, 0103 physical sciences, Intermittency, 010306 general physics
Abstract

Besides strong geodesic acoustic mode (GAM) activity, turbulence in the I-mode confinement regime of ASDEX Upgrade exhibits two prominent features, the weakly coherent mode (WCM) and strongly intermittent solitary density perturbations. The nonlinear interaction between these structures is studied in detail by means of a conditional averaged wavelet- bicoherence analysis. The wavelet analysis reveals that these density perturbations are at the WCM frequency. The GAM is coupled to all frequency scales of the velocity fluctuations via a modulational instability. The WCM shows coupling to higher frequencies prior to the bursts, indicating a process resembling wave-steepening. A possible mechanism for the generation of such solitary density perturbations by a Korteweg – de Vries-like nonlinearity is discussed. European Union (EUROfusion 633053)

Published
2017

8. Comparison of detailed experimental wavenumber spectra with gyrokinetic simulation aided by two-dimensional full-wave simulations

Author

Happel, T., Görler, T., Hennequin, Pascale, Lechte, C., Bernert, Matthias, Conway, G. D., Freethy, Simon, Honoré, Cyrille, Pinzón, J R, Stroth, Ulrich, The Asdex Upgrade, Team, Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Condensed Matter Physics, 01 natural sciences, Spectral line, 010305 fluids & plasmas, Computational physics, Full wave, Nuclear Energy and Engineering, Physics::Plasma Physics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, Wavenumber, Statistical physics, 010306 general physics
Abstract

International audience; The importance of using a comprehensive suite of tools for the validation of a gyrokinetic code is described. This is detailed by presenting experimental wavenumber spectra which show pronounced differences, although they are measured at the same toroidal, poloidal and radial location. They are obtained via Doppler reflectometry and the differences are due to the probing beam polarization. These differences are reproduced convincingly using turbulence from a gyrokinetic simulation as input for two-dimensional full-wave simulation. It is demonstrated that the application of synthetic diagnostics is indispensable if non-trivial diagnostics are used in the experiment. Furthermore, the measurement of wavenumber spectra via Doppler reflectometry with X-mode probing beam polarization might be problematic due to nonlinear wave?plasma interactions and should be regarded with care when used for quantitative statements or the validation of gyrokinetic codes.

Published
2017

9. Survey of the H-mode power threshold and transition physics studies in ASDEX Upgrade

Author

Ryter, F., Rathgeber, S. K., Barrera Orte, L., Bernert, M., Conway, G. D., Fischer, R., Happel, T., Kurzan, B., McDermott, R. M., Scarabosio, A., Suttrop, W., Viezzer, E., Willensdorfer, M., Wolfrum, E., ASDEX Upgrade Team, and ASDEX Upgrade Team

Subjects
Physics, Nuclear and High Energy Physics, Heat flux, ASDEX Upgrade, Electric field, Electron, Plasma, Atomic physics, Condensed Matter Physics, Pressure gradient, Magnetic field, Ion
Abstract

An overview of the H-mode threshold power in ASDEX Upgrade which addresses the impact of the tungsten versus graphite wall, the dependences upon plasma current and density, as well as the influence of the plasma ion mass is given. Results on the H–L back transition are also presented. Dedicated L–H transition studies with electron heating at low density, which enable a complete separation of the electron and ion channels, reveal that the ion heat flux is a key parameter in the L–H transition physics mechanism through the main ion pressure gradient which is itself the main contribution to the radial electric field and the induced flow shearing at the edge. The electron channel does not play any role. The 3D magnetic field perturbations used to mitigate the edge-localized modes are found to also influence the L–H transition and to increase the power threshold. This effect is caused by a flattening of the edge pressure gradient in the presence of the 3D fields such that the L–H transitions with and without perturbations occur at the same value of the radial electric field well, but at different heating powers.

Published
2013

10. Outer divertor of ASDEX Upgrade in low-density L-mode discharges in forward and reversed magnetic field: I. Comparison between measured plasma conditions and SOLPS5.0 code calculations

Author

Aho-Mantila, L., Wischmeier, M., Müller, H. W., Potzel, S., Coster, D. P., Bonnin, X., Conway, G. D., ASDEX Upgrade Team, and ASDEX Upgrade Team

Subjects
Physics, Nuclear and High Energy Physics, Field (physics), Plasma parameters, Divertor, Plasma, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, 12. Responsible consumption, Computational physics, Magnetic field, symbols.namesake, Mach number, ASDEX Upgrade, 0103 physical sciences, symbols, Langmuir probe, Atomic physics, 010306 general physics
Abstract

The scrape-off layer and divertor plasma conditions have been carefully analysed in dedicated ASDEX Upgrade experiments consisting of low-density L-mode discharges, with both forward and reversed toroidal magnetic fields and plasma currents. In the forward field, the outer divertor plasma is in a low-recycling regime with peak target temperature above 25 eV. In the reversed field with similar main plasma parameters, the target temperature is below 15 eV and the density is 5 times as high as in the forward field, indicating a higher recycling regime in the outer divertor. The SOLPS5.0 code package is used to model these divertor plasmas. Specifically, it is tested whether a combination of input assumptions exists that enables matching the code solution to all outer divertor diagnostic measurements, and whether these assumptions are compatible with constraints imposed by measurements outside the outer divertor. In the forward field, a good level of agreement with multiple outer target measurements is found with assumptions that simultaneously match the measured density and temperature profiles at the outer midplane, where the uncertainty in the radial position of the separatrix is ±0.5 cm. Similar approaches made previously for higher recycling regimes have not led to such a good consistency between all modelled and measured outer divertor parameters. In the reversed field with higher recycling in the outer divertor, a solution consistent with the outer target Langmuir probe measurements cannot be obtained, at least not without significantly compromising the match to the upstream profile measurements. Significant mismatches are observed also between the modelled and measured upstream Mach number in the forward field. These discrepancies question the global validity of the plasma solutions, and their origin is not yet clear. In part II (Aho-Mantila L. et al 2012 Nucl. Fusion 52 103007), the analysis of outer divertor conditions is complemented by local impurity migration studies, using the divertor plasma solutions presented in this paper.

Published
2012

11. Generation of blobs and holes in the edge of the ASDEX Upgrade tokamak

Author

Nold, B., Conway, G. D., Happel, T., Müller, H. W., Ramisch, M., Rohde, V., Stroth, U., ASDEX Upgrade Team, and ASDEX Upgrade Team

Subjects
Physics, Tokamak, Turbulence, Plasma parameters, Plasma, Condensed Matter Physics, Computational physics, law.invention, symbols.namesake, Nuclear Energy and Engineering, ASDEX Upgrade, Physics::Plasma Physics, law, Physics::Space Physics, symbols, Langmuir probe, Electric current, Atomic physics, Shear flow
Abstract

The intermittent character of turbulent transport is investigated with Langmuir probes in the scrape-off layer and across the separatrix of ASDEX Upgrade Ohmic discharges. Radial profiles of plasma parameters are in reasonable agreement with results from other diagnostics. The probability density functions of ion-saturation current fluctuations exhibit a parabolic relation between skewness and kurtosis. Intermittent blobs and holes are observed outside and inside the nominal separatrix, respectively. They seem to be born at the edge of the plasma and are not the foothills of avalanches launched in the plasma core. A strong shear flow was observed 1 cm radially outside the location where blobs and holes seem to be generated.

Published
2010

12. Frequency scaling and localization of geodesic acoustic modes in ASDEX Upgrade

Author

Conway, G. D., Tröster, C., Scott, B., Hallatschek, K., ASDEX Upgrade Team, and ASDEX Upgrade Team

Subjects
Physics, business.industry, Oscillation, Divertor, Radius, Zonal flow (plasma), Condensed Matter Physics, Scale factor, Computational physics, symbols.namesake, Optics, Amplitude, Nuclear Energy and Engineering, ASDEX Upgrade, symbols, business, Doppler effect
Abstract

The frequency behaviour and localization of the geodesic acoustic mode (GAM), believed to be a coherent plasma turbulence-generated Er × B zonal flow (ZF) oscillation, is studied in the ASDEX Upgrade tokamak using Doppler reflectometry. In typical elongated (1.4 < κ < 1.75) plasmas with an X-point divertor configuration the GAM is observed only in the edge density gradient region 0.95 < ρpol < 1.0 between the density pedestal top and the flux surface boundary. The GAM frequency (5–25 kHz) is found to scale linearly as ω = G cs/Ro (sound speed over major radius) but with an inverse dependence on the plasma elongation κ and a weak direct dependence on the safety factor q. The lower the GAM frequency the more important it is expected to become in moderating the turbulence via shear decorrelation. A heuristic scaling law for the frequency scale factor involving κ and finite aspect ratio terms has been obtained from dedicated parameter scans. For circular plasmas κ ~ 1 touching the limiter the density pedestal is weakened and the GAM is seen to reach in radially as far as ρpol ~ 0.75, depending on the q profile, with a frequency scale consistent with theoretical predictions. Radially the GAM frequency is not a smooth function but displays a series of plateaus a few centimetres wide coinciding with peaks in the GAM amplitude, suggesting several ZF layers. At the plateau edges the GAM spectral peak splits into two frequency branches.

Published
2008

13. Amplitude behaviour of geodesic acoustic modes in the ASDEX Upgrade tokamak

Author

Conway, G. D., ASDEX Upgrade Team, and ASDEX Upgrade Team

Subjects
Physics, Tokamak, Turbulence, Oscillation, business.industry, Divertor, Zonal flow (plasma), Condensed Matter Physics, Computational physics, law.invention, Amplitude, Optics, Nuclear Energy and Engineering, ASDEX Upgrade, law, Electron temperature, business
Abstract

The amplitude behaviour of the geodesic acoustic mode (GAM), a low frequency (5?25?kHz) coherent plasma turbulence-generated Er ? B zonal flow oscillation, is studied in the ASDEX Upgrade tokamak using Doppler reflectometry. Across the tokamak edge the GAM displays one or more maxima a few cm wide, coinciding with radial plateaus in the GAM frequency, suggesting nested zonal flow layers. The GAM peak amplitude ranges between 0.2 and 0.8?km?s?1, corresponding to several tens of per cent of the mean E ? B flow velocity. In limiter configurations, the GAM amplitude is found to decrease inversely with the plasma vertical elongation 1.1 < ? < 1.4, but rises again in X-point divertor configurations at higher ? ~ 1.6. At low ? the GAM amplitude increases with the safety factor q, consistent with damping effects, but becomes less sensitive to q at high ?. A positive linear dependence on the electron temperature gradient, an indicator of the linear turbulence drive, is also observed.

Published
2008

14. Characterisation of small ELM experiments in highly shaphed single null and quasi-double null plasmas in JET

Author

Saibene, G., Sartori, R., Günther, K., Meigs, A. G., Arshad, S. A., Bécoulet, M., Thomas, P. R., Monier-Garbet, M., Rimini, F. G., Koslowski, H. R., Perez, C. P., Stober, J., Loarte, A., Conway, G. D., Kempenaars, M. A. H., Ingesson, L. C., Lönnroth, J. S., Lomas, P. J., Parail, V., Zastrow, K. D., Andrew, Y., Sharapov, S., Korotkov, J. M., and McDonald, D. C.

Subjects
Physics, Nuclear and High Energy Physics, Jet (fluid), Pedestal, Magnetic confinement fusion, ddc:530, Plasma, Atomic physics, Magnetohydrodynamics, Collisionality, Condensed Matter Physics, Null (physics)
Abstract

This paper describes experiments with highly shaped JET H-mode plasmas, which were directed to developing regimes where Type I ELMs are replaced by other edge relaxations, while maintaining the pedestal pressure of Type I ELMy H-modes. It was found that Type II ELMs coexisted with Type I, up to densities of the order of the Greenwald limit, where Type III ELMs appear, and the good confinement was lost. Only at the highest edge collisionality was it observed that Type II ELMs completely replace Type I. At high beta(p) and q(95), 'grassy' ELMs replace Type I completely. The MHD spectra characteristics for grassy ELMs are significantly different from those of Type II ELMs. This paper details the experiments, briefly compares the results to those obtained elsewhere and suggests open lines of investigations for the assessment of the potential of grassy ELM regimes as an ELM mitigation technique.

Published
2005

15. The I-mode confinement regime at ASDEX Upgrade: global properties and characterization of strongly intermittent density fluctuations

Author

Happel, T., Manz, P., Ryter, F., Bernert, M., Dunne, M., Hennequin, Pascale, Hetzenecker, A., Stroth, U., Conway, G. D., Guimarais, L., Honoré, Cyrille, Viezzer, E., ASDEX Upgrade Team, The, Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, and European Union (UE)

Subjects
Tokamak, Radial electric field, 01 natural sciences, 010305 fluids & plasmas, law.invention, Pedestal, I­mode, ASDEX Upgrade, law, Physics::Plasma Physics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Electric field, 0103 physical sciences, Intermittency, 010306 general physics, ComputingMilieux_MISCELLANEOUS, Physics, Turbulence, Divertor, Plasma, Condensed Matter Physics, Magnetic field, Nuclear Energy and Engineering, Atomic physics, Confinement
Abstract

Properties of the I­mode confinement regime on the ASDEX Upgrade tokamak are summarized. A weak dependence of the power threshold for the L­I transition on the toroidal magnetic field strength is found. During improved confinement, the edge radial electric field well deepens. Stability calculations show that the I­mode pedestal is peeling­ballooning stable. Turbulence investigations reveal strongly intermittent density fluctuations linked to the weakly coherent mode in the confined plasma, which become stronger as the confinement quality increases. Across all investigated structure sizes ( ≈ ⊥ k 5 – 12 cm − 1 , with ⊥ k the perpendicular wavenumber of turbulent density fluctuations), the intermittent turbulence bursts are observed. Comparison with bolometry data shows that they move poloidally toward the X­point and finally end up in the divertor. This might be indicative that they play a role in inhibiting the density profile growth, such that no pedestal is formed in the edge density profile. European Union (EUROfusion 633053) European Union (EUROfusion AWP15­ENR­09/IPP­02)

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16. OVERVIEW OF PHYSICS STUDIES ON ASDEX UPGRADE

Author

Neville C. Luhmann, J. Mailloux, A. Kappatou, Yann Camenen, R. Arredondo Parra, P. Petersson, G. F. Harrer, I. Gomez Ortiz, E. Giovannozzi, S. S. Henderson, C. Sommariva, Thomas Schwarz-Selinger, G. Fuchert, Christopher G. Albert, P. Piovesan, A. Herrmann, C. Piron, Robert Lunsford, J. Hobirk, F. Clairet, L. Xiang, Carlo Cazzaniga, A. Burckhart, B. Kurzan, Bernhard Ploeckl, G. Kocsis, A. Mancini, Benoit Labit, M. Reich, N. den Harder, Faa Federico Felici, M. Oberparleiter, Tamás Szepesi, Sibylle Günter, K. Behler, R. Merkel, Ocleto D'Arcangelo, G. Haas, Alessandro Bortolon, T. B. Cote, E. Trier, P. Simon, A. Gude, Daniele Milanesio, Winfried Kernbichler, Dorothea Gradic, M. Rodriguez-Ramos, G.A. Rattá, G. Croci, O. Tudisco, E. Heyn, M. Groth, J. Gonzalez Martin, Olivier Sauter, Irena Ivanova-Stanik, Massimo Nocente, J. R. Harrison, Martin Heyn, C. Bruhn, C. Ham, L. Shao, M. Schubert, F. Brochard, Yu Gao, Bernd Heinemann, Sandra C. Chapman, Armin Manhard, S. S. Denk, A. Jardin, D. P. Coster, G. Schall, L. Horvath, Alexander Creely, Roman Schrittwieser, Patrick J. McCarthy, C. Castaldo, B. Wiringer, M. J. Mantsinen, Till Höschen, Ph. Lauber, V. Mertens, Anders Nielsen, G. Suarez, M. E. Manso, M. Dibon, S. Wiesen, Mirko Salewski, C. D. Challis, J. Schweinzer, D. Douai, Lorenzo Frassinetti, R. C. Wolf, Mirko Ramisch, P. de Marne, Yueqiang Liu, H. van den Brand, S. Nowak, E. Joffrin, M. Teschke, Karl Schmid, D. Silvagni, L. Giannone, D. I. Refy, E. Wolfrum, M. Sertoli, Chanho Moon, O. J. W. F. Kardaun, A. Ross, S. Elgeti, A. Shalpegin, G. D. Conway, A. Sigalov, Alberto Bottino, Benedikt Geiger, M. Willensdorfer, D. C. van Vugt, Mark Maraschek, W. Zhang, M. Oberkofler, M. Griener, Stylianos Varoutis, Bill Scott, F. Monaco, W. Suttrop, Helmut Faugel, Christian Hopf, J. Vicente, Gerhard Raupp, S. Fietz, Omar Maj, D. Terranova, Q. Yu, E. Seliunin, L. Gil, K. Lackner, I. Novikau, S. Heinzel, G. Birkenmeier, O. Linder, I. Zammuto, H. Fünfgelder, Alessandro Biancalani, D. Prisiazhniuk, Analiza M. Silva, Volker Hauer, Ulrich Stroth, M. Faitsch, Toke Koldborg Jensen, S. Brezinsek, S. Garavaglia, V. Nikolaeva, C. Angioni, T. Maceina, Antti Snicker, O. Schmitz, T. Vierle, A. Scarabosio, D. Carlton, F. Penzel, M. Tardocchi, Riccardo Maggiora, V. Plyusnin, A. Bergmann, A. Bock, G. Rocchi, Andreas Frank Martitsch, J. W. Coenen, I. Erofeev, Pierre Manas, J. Stober, O. Meyer, M. A. Van Zeeland, A. S. Jacobsen, H. Meister, Jens Madsen, E. Smigelskis, A. Lohs, T. Happel, A. Gallo, F. Ryter, P. A. Schneider, A. Kallenbach, Alf Köhn, C. Bottereau, I. Paradela Perez, N. Arden, M. Koubiti, Gergely Papp, Burkhard Plaum, Jorge Ferreira, P. Denner, H. Greuner, Daniel Told, M. Weiland, T. Hayward-Schneider, B. Sieglin, A. Buhler, B. Böswirth, A. Krämer-Flecken, F. Jaulmes, J. Galdon-Quiroga, M. Balden, J. Pinzón Acosta, C. Sozzi, T. Bolzonella, G. Neu, Simon Freethy, T. Sehmer, K. Höfler, T. T. Ribeiro, F. Mink, Ursel Fantz, Q. Yang, Jeppe Olsen, M. Wischmeier, P. Mantica, Timothy Goodman, R. Delogu, T. Tala, Panagiotis Tolias, A. Houben, G. Tardini, A. Kirk, T. Odstrcil, R. Fischer, J. Juul Rasmussen, D. Carralero, H. F. Meyer, P. Martin, J. Miettunen, E. Maljaars, Matthew Carr, Z. Yang, G. Pautasso, B. P. Duval, E. Sytova, Stefano Coda, D. Meshcheriakov, Morten Stejner, S. Zoletnik, Thomas Zehetbauer, M. Li, F. Liu, R. Neu, A. Drenik, P. Manz, E. Fable, Otto Asunta, Zhixin Lu, S. Kálvin, Bruce Lipschultz, Vinodh Bandaru, A. Di Siena, Mattia Siccinio, S. Costea, Frank Jenko, Peter Lang, V. Rohde, Manfred Zilker, F. Nabais, H. J. Sun, Chris Hegna, A. Krivska, M. Rott, S. E. Sharapov, Antoine Merle, J. Bernardo, K. Engelhardt, M. Garcia-Munoz, M. Kantor, M. Hölzl, J. M. Santos, L. Guimarais, A. Figuereido, Carlos B. da Silva, Ch. Day, P. David, U. von Toussaint, T. C. Blanken, D. A. Ryan, F. Palermo, Silvio Ceccuzzi, J.-M. Noterdaeme, M. Gobbin, A. Jansen van Vuuren, C.-P. Kasemann, D. Rittich, Wouter Tierens, Taina Kurki-Suonio, C. Martens, R. Riedl, Antti Hakola, A. Czarnecka, F. Hitzler, M. Spolaore, M. Tripský, D. Brida, A. V. Chankin, Alessandro Pau, T. Ilkei, K. Krieger, Emanuele Poli, Florian Laggner, J. F. Rivero-Rodriguez, Wolfgang Jacob, Nengchao Wang, Anne White, S. Kjer Hansen, Stefan Kragh Nielsen, M. Fröschle, R. Bilato, O. Kudlacek, Tobias Görler, A. Stegmeir, Ari Salmi, L. Colas, A. Mlynek, Istvan Cziegler, V. Bobkov, James Buchanan, A. Gräter, T. Luda di Cortemiglia, R. Drube, John Hammer Holm, Giuliana Sias, K. Galazka, Giuseppe Gorini, V. Igochine, B. Vanovac, O. P. Ford, A. Garcia-Carrasco, R. M. McDermott, B. Tal, A. Lebschy, M. Cavedon, Julia Fuchs, E. Viezzer, R. Dux, R.A. Pitts, Svetlana V. Ratynskaia, Aqsa Shabbir, Sergei Kasilov, M. Bernert, S. Saarelma, Gergö Pokol, F. Reimold, Geert Verdoolaege, M. Mayer, Marek Rubel, L. Sanchis-Sanchez, R. Maingi, William Hornsby, U. Plank, C. Cianfarani, N. Vianello, A. Huber, Gustavo Granucci, Didier Mazon, S. Glöggler, J. Simpson, I. Faust, G. L. Ravera, Laurie Porte, Johann Riesch, F. Janky, A Lyssoivan, T. Pütterich, F. Orain, M. Valisa, B. Esposito, C. Gleason-González, Juha Karhunen, M. Valovic, H. Maier, Gábor Cseh, A. Nemes-Czopf, E. Thoren, O. Pan, T. Eich, R. Coelho, M.R. de Baar, E. Strumberger, T. Hellsten, Lionello Marrelli, Boglarka Erdos, Pascale Hennequin, R. Ochoukov, H. Zohm, D. Wagner, Yevgen O. Kazakov, A. Medvedeva, M. G. Dunne, W. Treutterer, N. Leuthold, R. Zagórski, S. Potzel, V. Klevarova, Dirk Reiser, X. Wang, T. Lunt, Meyer, H, Angioni, C, Albert, C, Arden, N, Arredondo Parra, R, Asunta, O, De Baar, M, Balden, M, Bandaru, V, Behler, K, Bergmann, A, Bernardo, J, Bernert, M, Biancalani, A, Bilato, R, Birkenmeier, G, Blanken, T, Bobkov, V, Bock, A, Bolzonella, T, Bortolon, A, Boswirth, B, Bottereau, C, Bottino, A, Van Den Brand, H, Brezinsek, S, Brida, D, Brochard, F, Bruhn, C, Buchanan, J, Buhler, A, Burckhart, A, Camenen, Y, Carlton, D, Carr, M, Carralero, D, Castaldo, C, Cavedon, M, Cazzaniga, C, Ceccuzzi, S, Challis, C, Chankin, A, Chapman, S, Cianfarani, C, Clairet, F, Coda, S, Coelho, R, Coenen, J, Colas, L, Conway, G, Costea, S, Coster, D, Cote, T, Creely, A, Croci, G, Cseh, G, Czarnecka, A, Cziegler, I, D'Arcangelo, O, David, P, Day, C, Delogu, R, De Marne, P, Denk, S, Denner, P, Dibon, M, Di Siena, A, Douai, D, Drenik, A, Drube, R, Dunne, M, Duval, B, Dux, R, Eich, T, Elgeti, S, Engelhardt, K, Erdos, B, Erofeev, I, Esposito, B, Fable, E, Faitsch, M, Fantz, U, Faugel, H, Faust, I, Felici, F, Ferreira, J, Fietz, S, Figuereido, A, Fischer, R, Ford, O, Frassinetti, L, Freethy, S, Froschle, M, Fuchert, G, Fuchs, J, Funfgelder, H, Galazka, K, Galdon-Quiroga, J, Gallo, A, Gao, Y, Garavaglia, S, Garcia-Carrasco, A, Garcia-Munoz, M, Geiger, B, Giannone, L, Gil, L, Giovannozzi, E, Gleason-Gonzalez, C, Gloggler, S, Gobbin, M, Gorler, T, Gomez Ortiz, I, Gonzalez Martin, J, Goodman, T, Gorini, G, Gradic, D, Grater, A, Granucci, G, Greuner, H, Griener, M, Groth, M, Gude, A, Gunter, S, Guimarais, L, Haas, G, Hakola, A, Ham, C, Happel, T, Den Harder, N, Harrer, G, Harrison, J, Hauer, V, Hayward-Schneider, T, Hegna, C, Heinemann, B, Heinzel, S, Hellsten, T, Henderson, S, Hennequin, P, Herrmann, A, Heyn, M, Heyn, E, Hitzler, F, Hobirk, J, Hofler, K, Holzl, M, Hoschen, T, Holm, J, Hopf, C, Hornsby, W, Horvath, L, Houben, A, Huber, A, Igochine, V, Ilkei, T, Ivanova-Stanik, I, Jacob, W, Jacobsen, A, Janky, F, Jansen Van Vuuren, A, Jardin, A, Jaulmes, F, Jenko, F, Jensen, T, Joffrin, E, Kasemann, C, Kallenbach, A, Kalvin, S, Kantor, M, Kappatou, A, Kardaun, O, Karhunen, J, Kasilov, S, Kazakov, Y, Kernbichler, W, Kirk, A, Kjer Hansen, S, Klevarova, V, Kocsis, G, Kohn, A, Koubiti, M, Krieger, K, Krivska, A, Kramer-Flecken, A, Kudlacek, O, Kurki-Suonio, T, Kurzan, B, Labit, B, Lackner, K, Laggner, F, Lang, P, Lauber, P, Lebschy, A, Leuthold, N, Li, M, Linder, O, Lipschultz, B, Liu, F, Liu, Y, Lohs, A, Lu, Z, Luda Di Cortemiglia, T, Luhmann, N, Lunsford, R, Lunt, T, Lyssoivan, A, Maceina, T, Madsen, J, Maggiora, R, Maier, H, Maj, O, Mailloux, J, Maingi, R, Maljaars, E, Manas, P, Mancini, A, Manhard, A, Manso, M, Mantica, P, Mantsinen, M, Manz, P, Maraschek, M, Martens, C, Martin, P, Marrelli, L, Martitsch, A, Mayer, M, Mazon, D, Mccarthy, P, Mcdermott, R, Meister, H, Medvedeva, A, Merkel, R, Merle, A, Mertens, V, Meshcheriakov, D, Meyer, O, Miettunen, J, Milanesio, D, Mink, F, Mlynek, A, Monaco, F, Moon, C, Nabais, F, Nemes-Czopf, A, Neu, G, Neu, R, Nielsen, A, Nielsen, S, Nikolaeva, V, Nocente, M, Noterdaeme, J, Novikau, I, Nowak, S, Oberkofler, M, Oberparleiter, M, Ochoukov, R, Odstrcil, T, Olsen, J, Orain, F, Palermo, F, Pan, O, Papp, G, Paradela Perez, I, Pau, A, Pautasso, G, Penzel, F, Petersson, P, Pinzon Acosta, J, Piovesan, P, Piron, C, Pitts, R, Plank, U, Plaum, B, Ploeckl, B, Plyusnin, V, Pokol, G, Poli, E, Porte, L, Potzel, S, Prisiazhniuk, D, Putterich, T, Ramisch, M, Rasmussen, J, Ratta, G, Ratynskaia, S, Raupp, G, Ravera, G, Refy, D, Reich, M, Reimold, F, Reiser, D, Ribeiro, T, Riesch, J, Riedl, R, Rittich, D, Rivero-Rodriguez, J, Rocchi, G, Rodriguez-Ramos, M, Rohde, V, Ross, A, Rott, M, Rubel, M, Ryan, D, Ryter, F, Saarelma, S, Salewski, M, Salmi, A, Sanchis-Sanchez, L, Santos, J, Sauter, O, Scarabosio, A, Schall, G, Schmid, K, Schmitz, O, Schneider, P, Schrittwieser, R, Schubert, M, Schwarz-Selinger, T, Schweinzer, J, Scott, B, Sehmer, T, Seliunin, E, Sertoli, M, Shabbir, A, Shalpegin, A, Shao, L, Sharapov, S, Sias, G, Siccinio, M, Sieglin, B, Sigalov, A, Silva, A, Silva, C, Silvagni, D, Simon, P, Simpson, J, Smigelskis, E, Snicker, A, Sommariva, C, Sozzi, C, Spolaore, M, Stegmeir, A, Stejner, M, Stober, J, Stroth, U, Strumberger, E, Suarez, G, Sun, H, Suttrop, W, Sytova, E, Szepesi, T, Tal, B, Tala, T, Tardini, G, Tardocchi, M, Teschke, M, Terranova, D, Tierens, W, Thoren, E, Told, D, Tolias, P, Tudisco, O, Treutterer, W, Trier, E, Tripsky, M, Valisa, M, Valovic, M, Vanovac, B, Van Vugt, D, Varoutis, S, Verdoolaege, G, Vianello, N, Vicente, J, Vierle, T, Viezzer, E, Von Toussaint, U, Wagner, D, Wang, N, Wang, X, Weiland, M, White, A, Wiesen, S, Willensdorfer, M, Wiringer, B, Wischmeier, M, Wolf, R, Wolfrum, E, Xiang, L, Yang, Q, Yang, Z, Yu, Q, Zagorski, R, Zammuto, I, Zhang, W, Van Zeeland, M, Zehetbauer, T, Zilker, M, Zoletnik, S, Zohm, H, Meyer, H., Universidad de Sevilla, Departamento de Física Atómica, Molecular y Nuclear, Universidad de Sevilla. RNM138: Física Nuclear Aplicada, Universidad de Sevilla. TEP111: Ingeniería Mecánica, CEA Cadarache, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Culham Science Centre, Max-Planck-Institut für Plasmaphysik, Department of Applied Physics, Dutch Institute for Fundamental Energy Research, University of Lisbon, Eindhoven University of Technology, National Research Council of Italy, Princeton University, CEA, Forschungszentrum Jülich, Université de Lorraine, CNRS, Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile, University of Warwick, Swiss Federal Institute of Technology Lausanne, University of Innsbruck, University of Wisconsin-Madison, Massachusetts Institute of Technology, Hungarian Academy of Sciences, Soltan Institute for Nuclear Studies, University of York, Karlsruhe Institute of Technology, KTH Royal Institute of Technology, University of Seville, University of Milan - Bicocca, Fusion and Plasma Physics, VTT Technical Research Centre of Finland, Vienna University of Technology, Max-Planck Computing and Data Facility, General Atomics, Université Paris-Saclay, Graz University of Technology, Institut für Grenzflachenverfahrenstechnik und Plasmatechnologie, Danmarks Tekniske Universitet, Budapest University of Technology and Economics, Polish Academy of Sciences, Royal Military Academy, Ghent University, ITER Organization, University of California Davis, Polytechnic University of Turin, Barcelona Supercomputing Center, University College Cork, Chalmers University of Technology, University of Cagliari, ITER, CIEMAT, CAS - Institute of Plasma Physics, Max Planck Institute for Plasma Physics, Aalto-yliopisto, Aalto University, Angioni, C., Albert, C. G., Arden, N., Arredondo Parra, R., Asunta, O., De Baar, M., Balden, M., Bandaru, V., Behler, K., Bergmann, A., Bernardo, J., Bernert, M., Biancalani, A., Bilato, R., Birkenmeier, G., Blanken, T. C., Bobkov, V., Bock, A., Bolzonella, T., Bortolon, A., Boswirth, B., Bottereau, C., Bottino, A., Van Den Brand, H., Brezinsek, S., Brida, D., Brochard, F., Bruhn, C., Buchanan, J., Buhler, A., Burckhart, A., Camenen, Y., Carlton, D., Carr, M., Carralero, D., Castaldo, C., Cavedon, M., Cazzaniga, C., Ceccuzzi, S., Challis, C., Chankin, A., Chapman, S., Cianfarani, C., Clairet, F., Coda, S., Coelho, R., Coenen, J. W., Colas, L., Conway, G. D., Costea, S., Coster, D. P., Cote, T. B., Creely, A., Croci, G., Cseh, G., Czarnecka, A., Cziegler, I., D'Arcangelo, O., David, P., Day, C., Delogu, R., De Marne, P., Denk, S. S., Denner, P., Dibon, M., Di Siena, A., Douai, D., Drenik, A., Drube, R., Dunne, M., Duval, B. P., Dux, R., Eich, T., Elgeti, S., Engelhardt, K., Erdos, B., Erofeev, I., Esposito, B., Fable, E., Faitsch, M., Fantz, U., Faugel, H., Faust, I., Felici, F., Ferreira, J., Fietz, S., Figuereido, A., Fischer, R., Ford, O., Frassinetti, L., Freethy, S., Froschle, M., Fuchert, G., Fuchs, J. C., Funfgelder, H., Galazka, K., Galdon-Quiroga, J., Gallo, A., Gao, Y., Garavaglia, S., Garcia-Carrasco, A., Garcia-Munoz, M., Geiger, B., Giannone, L., Gil, L., Giovannozzi, E., Gleason-Gonzalez, C., Gloggler, S., Gobbin, M., Gorler, T., Gomez Ortiz, I., Gonzalez Martin, J., Goodman, T., Gorini, G., Gradic, D., Grater, A., Granucci, G., Greuner, H., Griener, M., Groth, M., Gude, A., Gunter, S., Guimarais, L., Haas, G., Hakola, A. H., Ham, C., Happel, T., Den Harder, N., Harrer, G. F., Harrison, J., Hauer, V., Hayward-Schneider, T., Hegna, C. C., Heinemann, B., Heinzel, S., Hellsten, T., Henderson, S., Hennequin, P., Herrmann, A., Heyn, M. F., Heyn, E., Hitzler, F., Hobirk, J., Hofler, K., Holzl, M., Hoschen, T., Holm, J. H., Hopf, C., Hornsby, W. A., Horvath, L., Houben, A., Huber, A., Igochine, V., Ilkei, T., Ivanova-Stanik, I., Jacob, W., Jacobsen, A. S., Janky, F., Jansen Van Vuuren, A., Jardin, A., Jaulmes, F., Jenko, F., Jensen, T., Joffrin, E., Kasemann, C. -P., Kallenbach, A., Kalvin, S., Kantor, M., Kappatou, A., Kardaun, O., Karhunen, J., Kasilov, S., Kazakov, Y., Kernbichler, W., Kirk, A., Kjer Hansen, S., Klevarova, V., Kocsis, G., Kohn, A., Koubiti, M., Krieger, K., Krivska, A., Kramer-Flecken, A., Kudlacek, O., Kurki-Suonio, T., Kurzan, B., Labit, B., Lackner, K., Laggner, F., Lang, P. T., Lauber, P., Lebschy, A., Leuthold, N., Li, M., Linder, O., Lipschultz, B., Liu, F., Liu, Y., Lohs, A., Lu, Z., Luda Di Cortemiglia, T., Luhmann, N. C., Lunsford, R., Lunt, T., Lyssoivan, A., Maceina, T., Madsen, J., Maggiora, R., Maier, H., Maj, O., Mailloux, J., Maingi, R., Maljaars, E., Manas, P., Mancini, A., Manhard, A., Manso, M. -E., Mantica, P., Mantsinen, M., Manz, P., Maraschek, M., Martens, C., Martin, P., Marrelli, L., Martitsch, A., Mayer, M., Mazon, D., Mccarthy, P. J., Mcdermott, R., Meister, H., Medvedeva, A., Merkel, R., Merle, A., Mertens, V., Meshcheriakov, D., Meyer, O., Miettunen, J., Milanesio, D., Mink, F., Mlynek, A., Monaco, F., Moon, C., Nabais, F., Nemes-Czopf, A., Neu, G., Neu, R., Nielsen, A. H., Nielsen, S. K., Nikolaeva, V., Nocente, M., Noterdaeme, J. -M., Novikau, I., Nowak, S., Oberkofler, M., Oberparleiter, M., Ochoukov, R., Odstrcil, T., Olsen, J., Orain, F., Palermo, F., Pan, O., Papp, G., Paradela Perez, I., Pau, A., Pautasso, G., Penzel, F., Petersson, P., Pinzon Acosta, J., Piovesan, P., Piron, C., Pitts, R., Plank, U., Plaum, B., Ploeckl, B., Plyusnin, V., Pokol, G., Poli, E., Porte, L., Potzel, S., Prisiazhniuk, D., Putterich, T., Ramisch, M., Rasmussen, J., Ratta, G. A., Ratynskaia, S., Raupp, G., Ravera, G. L., Refy, D., Reich, M., Reimold, F., Reiser, D., Ribeiro, T., Riesch, J., Riedl, R., Rittich, D., Rivero-Rodriguez, J. F., Rocchi, G., Rodriguez-Ramos, M., Rohde, V., Ross, A., Rott, M., Rubel, M., Ryan, D., Ryter, F., Saarelma, S., Salewski, M., Salmi, A., Sanchis-Sanchez, L., Santos, J., Sauter, O., Scarabosio, A., Schall, G., Schmid, K., Schmitz, O., Schneider, P. A., Schrittwieser, R., Schubert, M., Schwarz-Selinger, T., Schweinzer, J., Scott, B., Sehmer, T., Seliunin, E., Sertoli, M., Shabbir, A., Shalpegin, A., Shao, L., Sharapov, S., Sias, G., Siccinio, M., Sieglin, B., Sigalov, A., Silva, A., Silva, C., Silvagni, D., Simon, P., Simpson, J., Smigelskis, E., Snicker, A., Sommariva, C., Sozzi, C., Spolaore, M., Stegmeir, A., Stejner, M., Stober, J., Stroth, U., Strumberger, E., Suarez, G., Sun, H. -J., Suttrop, W., Sytova, E., Szepesi, T., Tal, B., Tala, T., Tardini, G., Tardocchi, M., Teschke, M., Terranova, D., Tierens, W., Thoren, E., Told, D., Tolias, P., Tudisco, O., Treutterer, W., Trier, E., Tripsky, M., Valisa, M., Valovic, M., Vanovac, B., Van Vugt, D., Varoutis, S., Verdoolaege, G., Vianello, N., Vicente, J., Vierle, T., Viezzer, E., Von Toussaint, U., Wagner, D., Wang, N., Wang, X., Weiland, M., White, A. E., Wiesen, S., Willensdorfer, M., Wiringer, B., Wischmeier, M., Wolf, R., Wolfrum, E., Xiang, L., Yang, Q., Yang, Z., Yu, Q., Zagorski, R., Zammuto, I., Zhang, W., Van Zeeland, M., Zehetbauer, T., Zilker, M., Zoletnik, S., Zohm, H., ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, and EUROfusion MST1 Team

Subjects
Magnetic confinement, Edge-localized modes (ELMs), Nuclear engineering, PLASMAS, Nuclear physics, 01 natural sciences, 010305 fluids & plasmas, ASDEX Upgrade, ITER, MODE, Physics, iter, Divertor, magnetic confinement, Magnetic confinement fusion, mode, Dissipation, Condensed Matter Physics, ddc, Tokamak physics, Física nuclear, tokamak physics, Tokamaks, FLUX, Nuclear and High Energy Physics, Technology and Engineering, DEMO, nuclear fusion, Electron cyclotron resonance, Resonant magnetic perturbations, Physics::Plasma Physics, 0103 physical sciences, Nuclear fusion, ddc:530, 010306 general physics, SOLID TUNGSTEN DIVERTOR, Física [Àrees temàtiques de la UPC], demo, plasmas, solid tungsten divertor, flux, ___, HEAVY ALLOYS, Magnetohydrodynamics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], heavy alloys
Abstract

The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heating power, flexible heating mix and comprehensive diagnostic set allows studies ranging from mimicking the scrape-off-layer and divertor conditions of ITER and DEMO at high density to fully non-inductive operation (q95 = 5.5, ) at low density. Higher installed electron cyclotron resonance heating power 6 MW, new diagnostics and improved analysis techniques have further enhanced the capabilities of AUG. Stable high-density H-modes with MW m−1 with fully detached strike-points have been demonstrated. The ballooning instability close to the separatrix has been identified as a potential cause leading to the H-mode density limit and is also found to play an important role for the access to small edge-localized modes (ELMs). Density limit disruptions have been successfully avoided using a path-oriented approach to disruption handling and progress has been made in understanding the dissipation and avoidance of runaway electron beams. ELM suppression with resonant magnetic perturbations is now routinely achieved reaching transiently . This gives new insight into the field penetration physics, in particular with respect to plasma flows. Modelling agrees well with plasma response measurements and a helically localised ballooning structure observed prior to the ELM is evidence for the changed edge stability due to the magnetic perturbations. The impact of 3D perturbations on heat load patterns and fast-ion losses have been further elaborated. Progress has also been made in understanding the ELM cycle itself. Here, new fast measurements of and Er allow for inter ELM transport analysis confirming that Er is dominated by the diamagnetic term even for fast timescales. New analysis techniques allow detailed comparison of the ELM crash and are in good agreement with nonlinear MHD modelling. The observation of accelerated ions during the ELM crash can be seen as evidence for the reconnection during the ELM. As type-I ELMs (even mitigated) are likely not a viable operational regime in DEMO studies of 'natural' no ELM regimes have been extended. Stable I-modes up to have been characterised using -feedback. Core physics has been advanced by more detailed characterisation of the turbulence with new measurements such as the eddy tilt angle—measured for the first time—or the cross-phase angle of and fluctuations. These new data put strong constraints on gyro-kinetic turbulence modelling. In addition, carefully executed studies in different main species (H, D and He) and with different heating mixes highlight the importance of the collisional energy exchange for interpreting energy confinement. A new regime with a hollow profile now gives access to regimes mimicking aspects of burning plasma conditions and lead to nonlinear interactions of energetic particle modes despite the sub-Alfvénic beam energy. This will help to validate the fast-ion codes for predicting ITER and DEMO. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 and 2019–2020 under grant agreement No. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. "Article signat per més de 100 autors/es: H. Meyer, for the AUG Team: D. Aguiam, C. Angioni, C.G. Albert, N. Arden, R. Arredondo Parra, O. Asunta, M. de Baar, M. Balden, V. Bandaru, K. Behler, A. Bergmann, J. Bernardo, M. Bernert, A. Biancalani, R. Bilato, G. Birkenmeier, T.C. Blanken, V. Bobkov, A. Bock, T. Bolzonella, A. Bortolon, B. Böswirth, C. Bottereau, A. Bottino, H. van den Brand, S. Brezinsek, D. Brida, F. Brochard, C. Bruhn, J. Buchanan, A. Buhler, A. Burckhart, Y. Camenen, D. Carlton, M. Carr, D. Carralero, C. Castaldo, M. Cavedon, C. Cazzaniga, S. Ceccuzzi, C. Challis, A. Chankin, S. Chapman, C. Cianfarani, F. Clairet, S. Coda, R. Coelho, J.W. Coenen, L. Colas, G.D. Conway, S. Costea, D.P. Coster, T.B. Cote, A. Creely, G. Croci, G. Cseh, A. Czarnecka, I. Cziegler, O. D'Arcangelo, P. David, C. Day, R. Delogu, P. de Marné, S.S. Denk, P. Denner, M. Dibon, A. Di Siena, D. Douai, A. Drenik, R. Drube, M. Dunne, B.P. Duval, R. Dux, T. Eich, S. Elgeti, K. Engelhardt, B. Erdös, I. Erofeev, B. Esposito, E. Fable, M. Faitsch, U. Fantz, H. Faugel, I. Faust, F. Felici, J. Ferreira, S. Fietz, A. Figuereido, R. Fischer, O. Ford, L. Frassinetti, S. Freethy, M. Fröschle, G. Fuchert, J.C. Fuchs, H. Fünfgelder, K. Galazka, J. Galdon-Quiroga, A. Gallo, Y. Gao, S. Garavaglia, A. Garcia-Carrasco, M. Garcia-Muñoz, B. Geiger, L. Giannone, L. Gil, E. Giovannozzi, C. Gleason-González, S. Glöggler, M. Gobbin, T. Görler, I. Gomez Ortiz, J. Gonzalez Martin, T. Goodman, G. Gorini, D. Gradic, A. Gräter, G. Granucci, H. Greuner, M. Griener, M. Groth, A. Gude, S. Günter, L. Guimarais, G. Haas, A.H. Hakola, C. Ham, T. Happel, N. den Harder, G.F. Harrer, J. Harrison, V. Hauer, T. Hayward-Schneider, C.C. Hegna, B. Heinemann, S. Heinzel, T. Hellsten, S. Henderson, P. Hennequin, A. Herrmann, M.F. Heyn, E. Heyn, F. Hitzler, J. Hobirk, K. Höfler, M. Hölzl, T. Höschen, J.H. Holm, C. Hopf, W.A. Hornsby, L. Horvath, A. Houben, A. Huber, V. Igochine, T. Ilkei, I. Ivanova-Stanik, W. Jacob, A.S. Jacobsen, F. Janky, A. Jansen van Vuuren, A. Jardin, F. Jaulmes, F. Jenko, T. Jensen, E. Joffrin, C.-P. Käsemann, A. Kallenbach, S. Kálvin, M. Kantor, A. Kappatou, O. Kardaun, J. Karhunen, S. Kasilov,, Y. Kazakov, W. Kernbichler, A. Kirk, S. Kjer Hansen, V. Klevarova, G. Kocsis, A. Köhn, M. Koubiti, K. Krieger, A. Krivska, A. Krämer-Flecken, O. Kudlacek, T. Kurki-Suonio, B. Kurzan, B. Labit, K. Lackner, F. Laggner, P.T. Lang, P. Lauber, A. Lebschy, N. Leuthold, M. Li, O. Linder, B. Lipschultz, F. Liu, Y. Liu, A. Lohs, Z. Lu, T. Luda di Cortemiglia, N.C. Luhmann, R. Lunsford, T. Lunt, A. Lyssoivan, T. Maceina, J. Madsen, R. Maggiora, H. Maier, O. Maj, J. Mailloux, R. Maingi, E. Maljaars, P. Manas, A. Mancini, A. Manhard, M.-E. Manso, P. Mantica, M. Mantsinen, P. Manz, M. Maraschek, C. Martens, P. Martin, L. Marrelli, A. Martitsch, M. Mayer, D. Mazon, P.J. McCarthy, R. McDermott, H. Meister, A. Medvedeva, R. Merkel, A. Merle, V. Mertens, D. Meshcheriakov, O. Meyer, J. Miettunen, D. Milanesio, F. Mink, A. Mlynek, F. Monaco, C. Moon, F. Nabais, A. Nemes-Czopf, G. Neu, R. Neu, A.H. Nielsen, S.K. Nielsen, V. Nikolaeva, M. Nocente, J.-M. Noterdaeme, I. Novikau, S. Nowak, M. Oberkofler, M. Oberparleiter, R. Ochoukov, T. Odstrcil, J. Olsen, F. Orain, F. Palermo, O. Pan, G. Papp, I. Paradela Perez, A. Pau, G. Pautasso, F. Penzel, P. Petersson, J. Pinzón Acosta, P. Piovesan, C. Piron, R. Pitts, U. Plank, B. Plaum, B. Ploeckl, V. Plyusnin, G. Pokol, E. Poli, L. Porte, S. Potzel, D. Prisiazhniuk, T. Pütterich, M. Ramisch, J. Rasmussen, G.A. Rattá, S. Ratynskaia, G. Raupp, G.L. Ravera, D. Réfy, M. Reich, F. Reimold, D. Reiser, T. Ribeiro, J. Riesch, R. Riedl, D. Rittich, J.F. Rivero-Rodriguez, G. Rocchi, M. Rodriguez-Ramos, V. Rohde, A. Ross1, M. Rott, M. Rubel, D. Ryan, F. Ryter, S. Saarelma, M. Salewski, A. Salmi, L. Sanchis-Sanchez, J. Santos, O. Sauter, A. Scarabosio, G. Schall, K. Schmid, O. Schmitz, P.A. Schneider, R. Schrittwieser, M. Schubert, T. Schwarz-Selinger, J. Schweinzer, B. Scott, T. Semer, E. Seliunin, M. Sertoli, A. Shabbir, A. Shalpegin, L. Shao, S. Sharapov, G. Sias, M. Siccinio, B. Sieglin, A. Sigalov, A. Silva, C. Silva, D. Silvagni, P. Simon, J. Simpson, E. Smigelskis, A. Snicker, C. Sommariva, C. Sozzi, M. Spolaore, A. Stegmeir, M. Stejner, J. Stober, U. Stroth, E. Strumberger, G. Suarez, H.-J. Sun, W. Suttrop, E. Sytova, T. Szepesi, B. Tál, T. Tala, G. Tardini, M. Tardocchi, M. Teschke, D. Terranova, W. Tierens, E. Thorén, D. Told, P. Tolias, O. Tudisco, W. Treutterer, E. Trier, M. Tripský, M. Valisa, M. Valovic, B. Vanovac, D. van Vugt, S. Varoutis, G. Verdoolaege, N. Vianello, J. Vicente, T. Vierle, E. Viezzer, U. von Toussaint, D. Wagner, N. Wang, X. Wang, M. Weiland, A.E. White, S. Wiesen, M. Willensdorfer, B. Wiringer, M. Wischmeier, R. Wolf, E. Wolfrum, L. Xiang, Q. Yang, Z. Yang, Q. Yu, R. Zagórski, I. Zammuto, W. Zhang, M. van Zeeland, T. Zehetbauer, M. Zilker, S. Zoletnik, H. Zohm and the EUROfusion MST1 Team55

Published
2018

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