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538 results on '"Sarazin, Y"'

1. Turbulent relaxation patterns in SOL plasma

Author

Varennes, R, Dif-Pradalier, G, Ghendrih, P, Grandgirard, V, Panico, O, Sarazin, Y, Serre, E, and Zarzoso, D

Subjects
Physics - Plasma Physics
Abstract

Relaxations of localized over-density in a plane transverse to the magnetic field are numericallyinvestigated under the effect of drift-wave and interchange drives in SOL conditions. Such a controlleddeparture from thermodynamic equilibrium allows the investigation of fundamental processesat play in cross-field transport. Interchange instabilities generate ballistic outward radial flux withlow amplitude zonal flow patterns, whereas drift-wave instabilities result in symmetric radial fluxwith large amplitude zonal flow patterns. When both instabilities are considered, the combinedeffects tend to favor drift-waves, leading to a weaker outward flux with larger zonal flow patterns.

Published
2024

2. Global linear stability analysis of kinetic Trapped Ion Mode (TIM) turbulence in tokamak plasma using spectral method

Author

Mandal, D., Lesur, M., Gravier, E., Sama, J. N., Guillevic, A., Sarazin, Y., and Garbet, X.

Subjects
Physics - Plasma Physics
Abstract

Trapped ion modes (TIM) belong to the family of ion temperature gradient (ITG) modes, which are one of the important ingredients in heat turbulent transport at the ion scale in tokamak plasmas. It is essential to properly estimate their linear growth rate to understand their influence on ion-scale turbulent transport. A global linear analysis of a reduced gyro-bounce kinetic model for trapped particle modes is performed, and a spectral method is proposed to solve the dispersion relation. Importantly, the radial profile of the particle drift velocity is taken into account in the linear analysis by considering the magnetic flux {\psi} dependency of the equilibrium Hamiltonian H_{eq}({\psi}) in the quasi-neutrality equation and equilibrium gyro-bounce averaged distribution function F_{eq} . Using this spectral method, linear growth-rates of TIM instability in presence of different temperature profiles and precession frequencies of trapped ions, with an approximated constant Hamiltonian and the exact {\psi} dependent equilibrium Hamiltonian, are investigated. The growth-rate depends on the logarithmic gradient of temperature \kappa_{T} , density \kappa_{n} and equilibrium Hamiltonian \kappa_{\Lambda} . With the exact {\psi} dependent Hamiltonian, the growth rates and potential profiles are modified significantly, compared to the cases with approximated constant Hamiltonian. All the results from the global linear analysis agree with a semi-Lagrangian based linear Vlasov solver with a good accuracy. This spectral method is very fast and requires very less computation resources compared to a linear version of Vlasov-solver based on a semi-Lagrangian scheme.

Published
2022
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3. The Problem of Marginality in Model Reductions of Turbulence

Author

Gillot, C., Dif-Pradalier, G., Sarazin, Y., Bourdelle, C., Camenen, Y., Citrin, J., Garbet, X., Ghendrih, Ph., Grandgirard, V., Manas, P., and Widmer, F.

Subjects
Physics - Plasma Physics
Abstract

Reduced quasilinear (QL) and nonlinear (gradient-driven) models with scale separations, commonly used to interpret experiments and to forecast turbulent transport levels in magnetised plasmas are tested against nonlinear models without scale separations (flux-driven). Two distinct regimes of turbulence -- either far above threshold or near marginal stability -- are investigated with Boltzmann electrons. The success of reduced models especially hinges on the reproduction of nonlinear fluxes. Good agreement between models is found above threshold whilst reduced models would significantly underpredict fluxes near marginality, overlooking mesoscale flow organisation and turbulence self-advection. Constructive prescriptions whereby to improve reduced models is discussed.

Published
2022
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4. Flux driven pedestal formation in tokamaks: turbulence simulations validated against the isotope effect

Author

De Dominici, G., Fuhr, G., Beyer, P., Bourdelle, C., Chôné, L., Cianfrani, F., Falchetto, G. L., Garbet, X., and Sarazin, Y.

Subjects
Physics - Plasma Physics
Abstract

The spontaneous pedestal formation above a power threshold at the edge of magnetically confined plasma is modelled for the first time in flux driven three-dimensional fluid simulations of electromagnetic turbulence with the code EMEDGE3D. The role of the collisional friction between trapped and passing particles is shown to be the key ingredient for shearing the radial electric field, hence stabilizing the turbulence, rather than the Maxwell and Reynolds stresses. The isotope effect, observed in many tokamaks worldwide, is recovered in EMEDGE3D simulations: the power threshold for pedestal formation is lower for Tritium than for Deuterium. The turbulence auto-correlation time is found to increase with the ion mass easing the radial electric shear stabilization, hence the pedestal formation., Comment: 7 pages, 7 figures

Published
2019

5. PoPe (Projection on Proper elements) for code control: verification, numerical convergence and reduced models. Application to plasma turbulence simulations

Author

Cartier-Michaud, T, Ghendrih, P, Sarazin, Y, Abiteboul, J, Bufferand, H, Dif-Pradalier, G, Garbet, X, Grandgirard, V, Latu, G, Norscini, C, Passeron, C, and Tamain, P

Subjects
Physics - Plasma Physics
Abstract

The Projection on Proper elements (PoPe) is a novel method of code control dedicated to 1) checking the correct implementation of models, 2) determining the convergence of numerical methods and 3) characterizing the residual errors of any given solution at very low cost. The basic idea is to establish a bijection between a simulation and a set of equations that generate it. Recovering equations is direct and relies on a statistical measure of the weight of the various operators. This method can be used in any dimensions and any regime, including chaotic ones. This method also provides a procedure to design reduced models and quantify the ratio costs to benefits. PoPe is applied to a kinetic and a fluid code of plasma turbulence.

Published
2015
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6. Transport Barrier generation at the interface of regions with different zonal flows dynamics

Author

Norscini, C., Ghendrih, Ph., Cartier-Michaud, T., Dif-Pradalier, G., Garbet, X., Nace, N., Sarazin, Y., and Tamain, P.

Subjects
Physics - Plasma Physics
Abstract

A novel and generic understanding of spontaneous generation of transport barriers and zonation regimes in turbulent self-organization is presented. It associates the barrier onset to the development of a spectral gap between large scale flows and turbulence modes leading to a zonation regime. A robust barrier builds-up at the interface of such a region and a neighboring one with reduced zonal flow generation. This more complex and generic transition paradigm could fit the numerous and sometimes conflicting observations as in fusion plasma experiments. Barrier relaxation by bursts of turbulence regenerate the zonal flows that are eroded by viscous (collisional-like) damping. The duration of the quiescent phase between the quasi-periodic relaxation events is governed by this damping process, hence the barrier collision frequency for fusion plasmas.

Published
2015

7. Plasma turbulence simulations with X-points using the flux-coordinate independent approach

Author

Hariri, F., Hill, P., Ottaviani, M., and Sarazin, Y.

Subjects
Physics - Plasma Physics
Abstract

In this work, the Flux-Coordinate Independent (FCI) approach to plasma turbulence simulations is formulated for the case of generic, static magnetic fields, including those possessing stochastic field lines. It is then demonstrated that FCI is applicable to nonlinear turbulent problems with and without X-point geometry. In particular, by means of simulations with the FENICIA code, it is shown that the standard features of ITG modes are recovered with reduced toroidal resolution. Finally, ITG turbulence under the influence of a static island is studied on the transport timescale with ITER-like parameters, showing the wide range of applicability of the method.

Published
2014
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8. A Singularity-Free Coordinate System for X-point Geometries

Author

Hariri, F., Hill, P., Ottaviani, M., and Sarazin, Y.

Subjects
Physics - Plasma Physics
Abstract

A Flux Coordinate Independent (FCI) approach for anisotropic systems, not based on magnetic flux coordinates has been introduced in [F. Hariri and M. Ottaviani, Comput. Phys. Commun., 184,2419 (2013)]. In this paper, we show that the approach can tackle magnetic configurations including X-points. Using the code FENICIA, an equilibrium with a magnetic island has been used to show the robustness of the FCI approach to cases in which a magnetic separatrix is present in the system, either by design or as a consequence of instabilities. Numerical results are in good agreement with the analytic solutions of the sound-wave propagation problem. Conservation properties are verified. Finally, the critical gain of the FCI approach in situations including the magnetic separatrix with an X-point is demonstrated by a fast convergence of the code with the numerical resolution in the direction of symmetry. The results highlighted in this paper show that the FCI approach should be able to address turbulent transport problems in X-point geometries., Comment: figures have been removed on purpose. Article submitted for publication with full content

Published
2014
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9. Magnetic energy cascade in spherical geometry: I. The stellar convective dynamo case

Author

Strugarek, A., Brun, A. S., Mathis, S., and Sarazin, Y.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics
Abstract

We present a method to characterize the spectral transfers of magnetic energy between scales in simulations of stellar convective dynamos. The full triadic transfer functions are computed thanks to analytical coupling relations of spherical harmonics based on the Clebsch-Gordan coefficients. The method is applied to mean field $\alpha\Omega$ dynamo models as benchmark tests. From the physical standpoint, the decomposition of the dynamo field into primary and secondary dynamo families proves very instructive in the $\alpha\Omega$ case. The same method is then applied to a fully turbulent dynamo in a solar convection zone, modeled with the 3D MHD ASH code. The initial growth of the magnetic energy spectrum is shown to be non-local. It mainly reproduces the kinetic energy spectrum of convection at intermediate scales. During the saturation phase, two kinds of direct magnetic energy cascades are observed in regions encompassing the smallest scales involved in the simulation. The first cascade is obtained through the shearing of magnetic field by the large scale differential rotation that effectively cascades magnetic energy. The second is a generalized cascade that involves a range of local magnetic and velocity scales. Non-local transfers appear to be significant, such that the net transfers cannot be reduced to the dynamics of a small set of modes. The saturation of the large scale axisymmetric dipole and quadrupole are detailed. In particular, the dipole is saturated by a non-local interaction involving the most energetic scale of the magnetic energy spectrum, which points out the importance of the magnetic Prandtl number for large-scale dynamos., Comment: 21 pages, 14 figures, 1 table, accepted for publication in the Astrophysical Journal

Published
2013
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10. Finding the Elusive E×B Staircase in Magnetized Plasmas

Author

Dif-Pradalier, G, Hornung, G, Ghendrih, Ph, Sarazin, Y, Clairet, F, Vermare, L, Diamond, PH, Abiteboul, J, Cartier-Michaud, T, Ehrlacher, C, Estève, D, Garbet, X, Grandgirard, V, Gürcan, ÖD, Hennequin, P, Kosuga, Y, Latu, G, Maget, P, Morel, P, Norscini, C, Sabot, R, and Storelli, A

Subjects
Mathematical Sciences, Physical Sciences, Engineering, General Physics
Abstract

Turbulence in hot magnetized plasmas is shown to generate permeable localized transport barriers that globally organize into the so-called "ExB staircase" [G. Dif-Pradalier et al., Phys. Rev. E, 82, 025401(R) (2010)]. Its domain of existence and dependence with key plasma parameters is discussed theoretically. Based on these predictions, staircases are observed experimentally in the Tore Supra tokamak by means of high-resolution fast-sweeping X-mode reflectometry. This observation strongly emphasizes the critical role of mesoscale self-organization in plasma turbulence and may have far-reaching consequences for turbulent transport models and their validation.

Published
2015

12. An overview of intrinsic torque and momentum transport bifurcations in toroidal plasmas

Author

Diamond, PH, Kosuga, Y, Gürcan, ÖD, McDevitt, CJ, Hahm, TS, Fedorczak, N, Rice, JE, Wang, WX, Ku, S, Kwon, JM, Dif-Pradalier, G, Abiteboul, J, Wang, L, Ko, WH, Shi, YJ, Ida, K, Solomon, W, Jhang, H, Kim, SS, Yi, S, Ko, SH, Sarazin, Y, Singh, R, and Chang, CS

Subjects
Atomic, Molecular, Nuclear, Particle and Plasma Physics, Fluids & Plasmas
Abstract

An overview of the physics of intrinsic torque is presented, with special emphasis on the phenomenology of intrinsic toroidal rotation in tokamaks, its theoretical understanding, and the variety of momentum transport bifurcation dynamics. Ohmic reversals and electron cyclotron heating-driven counter torque are discussed in some detail. Symmetry breaking by lower single null versus upper single null asymmetry is related to the origin of intrinsic torque at the separatrix. © 2013 IAEA, Vienna.

Published
2013

13. Predictions on heat transport and plasma rotation from global gyrokinetic simulations

Author

Sarazin, Y, Grandgirard, V, Abiteboul, J, Allfrey, S, Garbet, X, Ghendrih, Ph, Latu, G, Strugarek, A, Dif-Pradalier, G, Diamond, PH, Ku, S, Chang, CS, McMillan, BF, Tran, TM, Villard, L, Jolliet, S, Bottino, A, and Angelino, P

Subjects
Atomic, Molecular, Nuclear, Particle and Plasma Physics, Fluids & Plasmas
Abstract

Flux-driven global gyrokinetic codes are now mature enough to make predictions in terms of turbulence and transport in tokamak plasmas. Some of the recent breakthroughs of three such codes, namely GYSELA, ORB5 and XGC1, are reported and compared wherever appropriate. In all three codes, turbulent transport appears to be mediated by avalanche-like events, for a broad range of ρ* = ρi/a values, ratio of the gyro-radius over the minor radius. Still, the radial correlation length scales with ρi, leading to the gyro-Bohm scaling of the effective transport coefficient below ρ* ≈ 1/300. The possible explanation could be due to the fact that avalanches remain meso-scale due to the interaction with zonal flows, whose characteristic radial wavelength appears to be almost independent of the system size. As a result of the radial corrugation of the turbulence driven zonal and mean flows, the shear of the radial electric field can be significantly underestimated if poloidal rotation is assumed to be governed by the neoclassical theory, especially at low collisionality. Indeed, the turbulence contribution to the poloidal rotation increases when collisionality decreases. Finally, the numerical verification of toroidal momentum balance shows that both neoclassical and turbulent contributions to the Reynolds' stress tensor play the dominant role. The phase space analysis further reveals that barely passing supra-thermal particles mostly contribute to the toroidal flow generation, consistently with quasi-linear predictions.

Published
2011

14. Neoclassical physics in full distribution function gyrokinetics

Author

Dif-Pradalier, G, Diamond, PH, Grandgirard, V, Sarazin, Y, Abiteboul, J, Garbet, X, Ghendrih, Ph, Latu, G, Strugarek, A, Ku, S, and Chang, CS

Subjects
Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Classical Physics, Fluids & Plasmas
Abstract

Treatment of binary Coulomb collisions when the full gyrokinetic distribution function is evolved is discussed here. A spectrum of different collision operators is presented, differing through both the physics that can be addressed and the numerics they are based on. Eulerian-like (semi-Lagrangian) and particle in cell (PIC) (Monte-Carlo) schemes are successfully cross-compared, and a detailed confrontation to neoclassical theory is shown.

Published
2011

15. On the validity of the local diffusive paradigm in turbulent plasma transport.

Author

Dif-Pradalier, G, Diamond, PH, Grandgirard, V, Sarazin, Y, Abiteboul, J, Garbet, X, Ghendrih, Ph, Strugarek, A, Ku, S, and Chang, CS

Subjects
Fluids & Plasmas, Mathematical Sciences, Physical Sciences, Engineering
Abstract

A systematic, constructive and self-consistent procedure to quantify nonlocal, nondiffusive action at a distance in plasma turbulence is exposed and applied to turbulent heat fluxes computed from the state-of-the-art full- f, flux-driven gyrokinetic GYSELA and XGC1 codes. A striking commonality is found: heat transport below a dynamically selected mesoscale has the structure of a Lévy distribution, is strongly nonlocal, nondiffusive, scale-free, and avalanche mediated; at larger scales, we report the observation of a self-organized flow structure which we call the " E × B staircase" after its planetary analog.

Published
2010

16. Front propagation and critical gradient transport models

Author

Garbet, X, Sarazin, Y, Imbeaux, F, Ghendrih, P, Bourdelle, C, Gürcan, ÖD, and Diamond, PH

Subjects
Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Classical Physics, Fluids & Plasmas
Abstract

This paper analyzes the properties of a two-field critical gradient model that couples a heat equation to an evolution equation for the turbulence intensity. It is shown that the dynamics of a perturbation is ballistic or diffusive depending on the shape of the pulse and also on the distance of the temperature gradient to the instability threshold. This dual character appears in the linear response of this model for a wave packet. It is recovered when investigating the nonlinear solutions of this system. Both self-similar diffusive fronts and ballistic fronts are shown to exist. When the propagation is ballistic, it is found that the front velocity is the geometric mean between the turbulent diffusion coefficient and a microinstability growth rate. © 2007 American Institute of Physics.

Published
2007

19. Safety factor influence on the edge E  ×  B velocity establishment in tokamak plasmas.

Author

Varennes, R, Vermare, L, Garbet, X, Hennequin, P, Dif-Pradalier, G, Sarazin, Y, Grandgirard, V, Panico, O, Donnel, P, and Obrejan, K

Subjects
SAFETY factor in engineering, PLASMA turbulence, TOKAMAKS, VELOCITY, ION temperature, REYNOLDS stress, ELECTRIC fields
Abstract

This study is motivated by experiments on Tore Supra and WEST tokamaks where a deepening of the E × B velocity—governed by the radial electric field Er —near the edge is observed when the safety factor decreases in L-mode plasmas. Flux-driven global simulations of ion temperature gradient turbulence recover qualitatively the trend observed in the experiments, i.e. the E × B velocity increases when decreasing the safety factor. From these simulations, multiple clues point out the role of turbulence in the establishment of the radial electric field even though the turbulent intensity increases with the safety factor. The proposed mechanism to elucidate this phenomenon, backed up by a reduced model, is that the damping of the poloidal flow, governed by the neoclassical friction, increases more strongly with the safety factor than the turbulent drive for Er, due to the (r , θ) component of the Reynolds stress. [ABSTRACT FROM AUTHOR]

Published
2024
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20. The problem of capturing marginality in model reductions of turbulence

Author

Gillot, C, primary, Dif-Pradalier, G, additional, Sarazin, Y, additional, Bourdelle, C, additional, Bañón Navarro, A, additional, Camenen, Y, additional, Citrin, J, additional, Di Siena, A, additional, Garbet, X, additional, Ghendrih, Ph, additional, Grandgirard, V, additional, Manas, P, additional, and Widmer, F, additional

Published
2023
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23. Physics of E x B staircases

Author

Dif-Pradalier, G., Clairet, F., Diamond, P., Donnel, P., Garbet, X., Ghendrih, V., Grandgirard, A., Medvedeva, A., Milovanov, A., Sarazin, Y., Vermare, L., Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), University of California [San Diego] (UC San Diego), University of California (UC), UCSD-CNRS Joint Research Chemistry Laboratory (UMI 3555), University of California (UC)-University of California (UC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), CEA Cadarache, Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Italian National agency for new technologies, Energy and sustainable economic development [Frascati] (ENEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, 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
[PHYS]Physics [physics], [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
Abstract

International audience

Published
2022

24. Internal Transport Barriers in Magnetised Plasmas

Author

Garbet, X., Ghendrih, P., Sarazin, Y., Beyer, P., Figarella, C., Benkadda, S., Burton, W.B., editor, Kuijpers, J. M. E., editor, Van Den Heuvel, E. P. J., editor, Van Der Laan, H., editor, Appenzeller, I., editor, Bahcall, J. N., editor, Bertola, F., editor, Cassinelli, J. P., editor, Cesarsky, C. J., editor, Engvold, O., editor, McCray, R., editor, Murdin, P. G., editor, Pacini, F., editor, Radhakrishnan, V., editor, Sato, K., editor, Shu, F. H., editor, Somov, B. V., editor, Sunyaev, R. A., editor, Tanaka, Y., editor, Tremaine, S., editor, Weiss, N. O., editor, Sharma, A. Surjalal, editor, and Kaw, Predhiman K., editor

Published
2005
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26. New advances to prepare GYSELA-X code for exascale global gyrokinetic plasma turbulence simulations: porting on GPU and ARM architectures

Author

Grandgirard, Virginie, Obrejan, Kevin, Midou, Dorian, Asahi, Y, Bernard, P-E, Bigot, J, Bourne, E, Dechard, J, Dif- Pradalier, G, Donnel, P, Garbet, X, Gueroudji, A, Hager, G, Murai, H, Ould-Ruis, Yacine, Padioleau, T, Nguyen, L, Peybernes, M, Sarazin, Y, Sato, M, Tsuji, M, Vezolle, P, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Japan Atomic Energy Agency, Hewlett Packard Enterprise (Hewlett Packard) (HPE), Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), AS+ Groupe EOLEN, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), RIKEN Center for Computational Science [Kobe] (RIKEN CCS), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Data Aware Large Scale Computing (DATAMOVE ), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire d'Informatique de Grenoble (LIG), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Ecole Polytechnique Fédérale de Lausanne (EPFL), the Association for Computing Machinery (ACM), and the Swiss National Supercomputing Centre (CSCS)

Subjects
[NLIN]Nonlinear Sciences [physics]
Abstract

International audience

Published
2022

27. Synergy of Turbulent Momentum Drive and Magnetic Braking

Author

Varennes, R., primary, Garbet, X., additional, Vermare, L., additional, Sarazin, Y., additional, Dif-Pradalier, G., additional, Grandgirard, V., additional, Ghendrih, P., additional, Donnel, P., additional, Peret, M., additional, Obrejan, K., additional, and Bourne, E., additional

Published
2022
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31. Safety factor impact on the radial electric field in gyrokinetic simulations

Author

Varennes, R, Peret, M, Vermare, L., Garbet, X, Sarazin, Y, Grandgirard, V, Dif- Pradalier, G, Gendrih, P, Donnel, P, Varennes, Robin, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, 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
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
Abstract

International audience

Published
2022

32. Intrinsic rotation drive in tokamaks: the competition between turbulence and magnetic braking

Author

Varennes, R, Garbet, X, Vermare, L., Sarazin, Y, Dif-Pradalier, G, Grandgirard, V, Ghendrih, P, Donnel, P, Peret, M, Obrejan, K, Bourne, E, Varennes, Robin, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, 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
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
Abstract

This workshop is devoted to the theory of magnetic confinement systems; International audience

Published
2022

33. Operating a full tungsten actively cooled tokamak: overview of WEST first phase of operation

Author

Bucalossi, J., Achard, J., Agullo, O., Alarcon, T., Allegretti, L., Ancher, H., Antar, G., Antusch, S., Anzallo, V., Arnas, C., Arranger, D., Artaud, J. F., Aumeunier, M. H., Baek, S. G., Bai, X., Balbin, J., Balorin, C., Barbui, T., Barbuti, A., Barlerin, J., Basiuk, V., Batal, T., Baulaigue, O., Bec, A., Bécoulet, M., Benoit, E., Benard, E., Benard, J. M., Bertelli, N., Bertrand, E., Beyer, P., Bielecki, J., Bienvenu, P., Bisson, R., Bobkov, V., Bodner, G., Bottereau, C., Bouchand, C., Bouquey, F., Bourdelle, C., Bourg, J., Brezinsek, S., Brochard, F., Brun, C., Bruno, V., Bufferand, H., Bureau, A., Burles, S., Camenen, Y., Cantone, B., Caprin, E., Carpentier, S., Caulier, G., Chanet, N., Chellai, O., Chen, Y., Chernyshova, M., Chmielewski, P., Choe, W., Chomiczewska, A., Ciraolo, G., Clairet, F., Coenen, J., Colas, L., Colledani, G., Colnel, J., Coquillat, P., Corbel, E., Corre, Y., Costea, S., Courtois, X., Czarski, T., Daniel, R., Daumas, J., De Combarieu, M., Temmerman, G., De, De Vries, P., Dechelle, C., Deguara, F., Dejarnac, R., Delaplanche, J. M., Delgado-Aparicio, L. F., Delmas, E., Delpech, L., Desgranges, C., Devynck, P., Di Genova, S., Diab, R., Diallo, A., Diez, M., Dif-Pradalier, G., Dimitrova, M., Ding, B., Dittmar, T., Doceul, L., Domenes, M., Douai, D., Dougnac, H., Duan, X., Dubus, L., Dumas, N., Dumont, R., Durand, F., Durif, A., Durocher, A., Durodié, F., Ekedahl, A., Elbeze, D., Ertmer, S., Escarguel, A., Escourbiac, F., Ezato, K., Faisse, F., Faure, N., Fedorczak, N., Fejoz, P., Fenzi-Bonizec, C., Ferlay, F., Firdaouss, M., Fleury, L., Flouquet, D., Gallo, A., Gao, Y., Garbet, X., Garcia, J., Gardarein, J. L., Gargiulo, L., Garibaldi, P., Garitta, S., Gaspar, J., Gauthier, E., Gavila, P., Gazzotti, S., Gely, F., Geynet, M., Gharafi, S., Ghendrih, P., Giacalone, I., Gil, C., Ginoux, S., Girard, S., Giroux, E., Giruzzi, G., Goletto, C., Goniche, M., Gray, T., Grelier, E., Greuner, H., Grigore, E., Grisolia, C., Grosjean, A., Grosman, A., Guibert, D., Guilhem, D., Guillemaut, C., Guillermin, B., Guirlet, R., Gunn, J. P., Gunsu, Y., Gyergyek, T., Hakola, A., Harris, J., Hatchressian, J. C., Helou, W., Hennequin, P., Hernandez, C., Hill, K., Hillairet, J., Hirai, T., Hoang, G. T., Houry, M., Hutter, T., Imbeaux, F., Imbert, N., Ivanova-Stanik, I., Jalageas, R., Jardin, A., Jaubert, L., Jiolat, G., Jonas, A., Joubert, P., Kirschner, A., Klepper, C., Komm, M., Koubiti, M., Kovacic, J., Kozeiha, M., Krieger, K., Krol, K., Lacroix, B., Laguardia, L., Lamaison, V., Laqua, H., Lau, C., Lausenaz, Y., Lé, R., Le Bohec, M., Lefevre, N., Lemoine, N., Lerche, E., Lewerentz, M., Li, Y., Li, M., Liang, A., Linczuk, P., Linsmeier, C., Lipa, M., Litaudon, X., Liu, X., Llorens, J., Loarer, T., Loarte, A., Loewenhoff, T., Lombard, G., Lore, J., Lorenzetto, P., Lotte, P., Lozano, M., Lu, B., Lunsford, R., Luo, G., Magaud, P., Maget, P., Mahieu, J. F., Maini, P., Malard, P., Malinowski, K., Manas, P., Manenc, L., Marandet, Y., Marechal, J. L., Marek, S., Martin, C., Martin, E., Martinez, A., Martino, P., Mazon, D., Messina, P., Meunier, L., Midou, D., Mineo, Y., Missilian, M., Mitteau, R., Mitu, B., Mollard, P., Moncada, V., Mondiere, T., Morales, J., Moreau, M., Moreau, P., Moudden, Y., Moureau, G., Mouyon, D., Muraglia, M., Nagy, A., Nakano, T., Nardon, E., Neff, A., Nespoli, F., Nichols, J., Nicollet, S., Nouailletas, R., Ono, M., Ostuni, V., Parish, C., Park, H., Parrat, H., Pascal, J. Y., Pégourié, B., Pellissier, F. P., Peneliau, Y., Peret, M., Peysson, Y., Pignoly, E., Pintsuk, G., Pitts, R., Pocheau, C., Portafaix, C., Poulos, M., Prochet, P., Puig Sitjes, A., Rasinski, M., Raup, G., Regal-Mezin, X., Reux, C., Riccardi, B., Rice, J., Richou, M., Rigollet, F., Roche, H., Romazanov, J., Ruset, C., Sabot, R., Saille, A., Sakamoto, R., Salmon, T., Samaille, F., Santagiustina, A., Santraine, B., Sarazin, Y., Serre, E., Shin, H., Shiraiwai, S., Signoret, Ja., Signoret, Je., Simonin, A., Skalli Fettachi, O., Song, Y., Spring, A., Spuig, P., Sridhar, S., Stratton, B., Talatizi, C., Tamain, P., Tatali, R., Téna, M., Torre, A., Toulouse, L., Travère, J. M., Treutterer, W., Tsitrone, E., Unterberg, E., Urbanczyk, G., Van Eester, D., Van Rooij, G., Vartanian, S., Verger, J. M., Vermare, L., Vézinet, D., Vignal, N., Vincent, B., Vives, S., Volpe, D., Wallace, G., Wang, E., Wang, L., Wang, Yi., Wang, Yo., Wauters, T., Wirth, B., Wirtz, M., Wojenski, A., Wright, J., Xu, M., Yang, Q., Yang, H., Zago, B., Zagorski, Zhang, B., Zhang, X., Zou, X., Institut universitaire des systèmes thermiques industriels (IUSTI), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, 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
Nuclear and High Energy Physics, Tokamak, Materials science, WEST, Nuclear engineering, Phase (waves), chemistry.chemical_element, Tungsten, law.invention, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], law, ITER, divertor, DEMO, Engineering & allied operations, nuclear fusion, Superconductivity, [PHYS]Physics [physics], Divertor, RF power amplifier, magnetic confinement, Plasma, Condensed Matter Physics, chemistry, Heat flux, ddc:620, tokamak physics
Abstract

WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up to 1000 s. In support of ITER operation and DEMO conceptual activities, key missions of WEST are: (i) qualification of high heat flux plasma-facing components in integrating both technological and physics aspects in relevant heat and particle exhaust conditions, particularly for the tungsten monoblocks foreseen in ITER divertor; (ii) integrated steady-state operation at high confinement, with a focus on power exhaust issues. During the phase 1 of operation (2017–2020), a set of actively cooled ITER-grade plasma facing unit prototypes was integrated into the inertially cooled W coated startup lower divertor. Up to 8.8 MW of RF power has been coupled to the plasma and divertor heat flux of up to 6 MW m−2 were reached. Long pulse operation was started, using the upper actively cooled divertor, with a discharge of about 1 min achieved. This paper gives an overview of the results achieved in phase 1. Perspectives for phase 2, operating with the full capability of the device with the complete ITER-grade actively cooled lower divertor, are also described.

Published
2022
Full Text
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34. Interplay between magnetic braking and turbulent stress tensor regarding plasma flow

Author

Varennes, R, Gendrih, P, Vermare, L., Garbet, X, Sarazin, Y, Grandgirard, V, Dif- Pradalier, G, Donnel, P, Peret, M, Varennes, Robin, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, 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
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
Abstract

International audience

Published
2022

35. Characterisation of Fullerene Schottky Diodes

Author

Curran, S., Callaghan, J., Weldon, D., Bourdin, E., Cazini, K., Blau, W. J., Waldron, E., McGoveran, D., Delamesiere, M., Sarazin, Y., Hogrel, C., Cardona, Manuel, editor, Fulde, Peter, editor, von Klitzing, Klaus, editor, Queisser, Hans-Joachim, editor, Lotsch, Helmut K. V., editor, Kuzmany, Hans, editor, Fink, Jörg, editor, Mehring, Michael, editor, and Roth, Siegmar, editor

Published
1993
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36. Full-f gyrokinetic simulations of Ohmic L-mode plasmas in linear and saturated Ohmic confinement regimes.

Author

Idomura, Y., Dif-Pradalier, G., Garbet, X., and Sarazin, Y.

Subjects
PLASMA turbulence, DEUTERIUM ions, DOPPLER effect, TOROIDAL plasma, SHEARING force, FREQUENCY spectra, ION temperature
Abstract

Two time slices in linear and saturated Ohmic confinement (LOC and SOC) regimes in a Tore Supra Ohmic L-mode discharge are analyzed using nonlinear global full-f gyrokinetic simulations, and qualitative features of the LOC–SOC transition are reproduced. The exhaust of carbon impurity ions is caused by ion mixing, which is driven by the toroidal field stress. The intrinsic rotation develops in the opposite direction between the LOC and SOC phases, which is characterized by different features of the mode asymmetry between trapped electron modes (TEMs) in the LOC phase and ion temperature gradient-driven modes in the SOC phase, leading to the change of the profile shear stress. Here, the mode asymmetry or the ballooning angle depends not only on the profile shear and the Er shear but also on the radial electric field Er itself. The energy fluxes of electrons and deuterium ions are dominant in the LOC and SOC phases, respectively, and the ratio of the energy confinement time between the two phases agree with the experimental value. Turbulent frequency spectra are characterized by quasi-coherent modes (QCMs) and broad-band spectra in the LOC and SOC phases, respectively. The QCMs are produced by a split of the toroidal mode number spectra of TEMs induced by the Doppler shift of poloidal E × B rotation due to Er, which is sustained in the electron diamagnetic direction by the ripple induced counter-current rotation, and enhanced by higher temperature in the LOC phase. [ABSTRACT FROM AUTHOR]

Published
2023
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38. Impact of non-axisymmetric magnetic field perturbations on flows

Author

Varennes, R, Garbet, X, Vermare, L, Sarazin, Y, Grandgirard, V, Dif-Pradalier, Guilhem, Peret, M, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), 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), European Project: 633053,H2020,EURATOM-Adhoc-2014-20,EUROfusion(2014), icard, valerie, and Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium - EUROfusion - - H20202014-01-01 - 2018-12-31 - 633053 - VALID

Subjects
[PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience

Published
2021

42. How to prepare the GYSELA-X code to future exascale edge-core simulations

Author

Grandgirard, Virginie, Asahi, Y, Bigot, J, Bourne, E, Dif-Pradalier, Guilhem, Donnel, P, Garbet, X, Ghendrih, Ph., Güçlü, Yaman, Kormann, K, Midou, D, Munschy, Y, Obrejan, K, Passeron, Ch, Varennes, R, Sarazin, Y, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Japan Atomic Energy Agency, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique Fédérale de Lausanne (EPFL), Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Association for Computing Machinery (ACM), and the Swiss National Supercomputing Centre (CSCS)

Subjects
[PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2021

43. Flux driven pedestal formation above a certain source Flux driven pedestal formation in tokamaks: Turbulence simulations validated against the isotope effect

Author

Bourdelle, C, de Dominici, G, Fuhr, G, Beyer, P, Chôné, L, Cianfrani, F, Falchetto, G, Garbet, X, Sarazin, Y, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Aalto University, IAEA, and icard, valerie

Subjects
[PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience

Published
2021

44. Interplay between core, edge and scrape-off layer in turbulent magnetised plasmas: Lessons learnt from an information theoretic measure, the 'transfer entropy' to assess causality in nonlinear plasma dynamics

Author

Dif-Pradalier, G., Ph. Ghendrih, Sarazin, Y., Garbet, X., Grandgirard, V., Munschy, Y., Varennes, R., laure vermare, Camenen, Y., Widmer, F., Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), European Project: 633053,H2020,EURATOM-Adhoc-2014-20,EUROfusion(2014), European Project: 824158,H2020-EU.1.4. - EXCELLENT SCIENCE - Research Infrastructures ,EoCoE-II(2019), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), and European Project: 824158,EoCoE-II

Subjects
[PHYS]Physics [physics], [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
Abstract

International audience; The present manuscript is meant to provide a companion pedagogical approach to an information theoretic measure, the "Transfer Entropy" method, useful to assess causality in complex (time series) datasets. This manuscript describes useful basics for the forthcoming discussion on the causal chain of events that leads to the onset of a spontaneous and stable edge transport barrier in flux-driven gyrokinetics when core, edge and scrape-off layer regions self-consistently interplay.

Published
2021

45. Impact of the aspect ratio on tokamak reactor design

Author

Sarazin, Y, Duchateau, J.-L, Garbet, X, Ghendrih, R, Guirlet, J, Hillairet, B, Pégourié, A, Torre, R, Varennes, R, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Institut de Recherche sur la Fusion par confinement Magnétique (IRFM)

Subjects
[PHYS]Physics [physics]
Abstract

International audience; The impact of the aspect ratio R/a (major over minor radius) on the design of tokamak reactors is addressed by means of the generic and comprehensive 0-dimensional ScaLa model for tokamak dimensioning. The European DEMO (fusion gain Q=40 and power P$_{fus}$=2.037GW) is taken as the target. Three scaling laws are considered for the energy confinement time, namely IPB98(y,2) used as the ITER reference, the electrostatic DS03 law and the recently upgraded ITPA20 one. First, it appears that the increase of the energy confinement time with A found in two of the scaling laws does not necessarily result in an advantage of working at large A, cross-dependencies leading to sometimes counter-intuitiveyet realtrends. Second, the opposite trends with respect to a scan in A which is observed regarding the product of the plasma volume times the square of the magnetic fieldused as a proxy for the costdoes not provide a clear answer as to whether small or large aspect ratio tokamaks should be favoured. This mild conclusion pushes for consolidating experimental databases with tokamaks exhibiting aspect ratios departing from the common 3 value.

Published
2021

49. Key role of phase dynamics & diamagnetic drive on Reynolds stress in fusion plasma turbulence

Author

Sarazin, Y., Dif-Pradalier, Guilhem, Ghendrih, Ph., Garbet, X., Berger, A., Bigué, R., Bourne, Emilie, Grandgirard, Virginie, Obrejan, Kevin, Varennes, R., Vermare, L., icard, valerie, Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium - EUROfusion - - H20202014-01-01 - 2018-12-31 - 633053 - VALID, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), 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), and European Project: 633053,H2020,EURATOM-Adhoc-2014-20,EUROfusion(2014)

Subjects
[PHYS]Physics [physics], [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience

Published
2021

50. Compressing the time series of five dimensional distribution function data from gyrokinetic simulation using principal component analysis

Author

Asahi, Y., Fujii, K., Heim, D.M., Maeyama, S., Garbet, X., Grandgirard, V., Sarazin, Y., Dif-Pradalier, G., Idomura, Y., Yagi, M., and Publica

Abstract

Phase space structures are extracted from the time series of five dimensional distribution function data computed by the flux-driven full-f gyrokinetic code GT5D. Principal component analysis (PCA) is applied to reduce the dimensionality and the size of the data. Phase space bases in (𝜑,𝑣∥,𝑤) and the corresponding spatial coefficients (poloidal cross section) are constructed by PCA, where 𝜑, 𝑣∥, and w, respectively, mean the toroidal angle, the parallel velocity, and the perpendicular velocity. It is shown that 83% of the variance of the original five dimensional distribution function can be expressed with 64 principal components, i.e., the compression of the degrees of freedom from 1.3×1012 to 1.4×109. One of the important findings-resulting from the detailed analysis of the contribution of each principal component to the energy flux-deals with avalanche events, which are found to be mostly driven by coherent structures in the phase space, indicating the key role of resonant particles. Another advantage of the proposed analysis is the decoupling of 6D (1D time and 5D phase space) data into the combinations of 3D data which are visible to the human eye.

Published
2021

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