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  • Full radius linear and nonlinear gyrokinetic simulations for tokamaks and stellarators : zonal flows, applied EpsilonxBeta flows, trapped electrons and finite beta

Abstract

The aim of this paper is to report on recent advances made in global gyrokinetic simulations of ion temperature gradient (ITG) modes and other microinstabilities. The nonlinear development and saturation of ITG modes and the role of Epsilon × Beta zonal flows are studied with a global nonlinear Delta f formulation that retains parallel nonlinearity and thus allows for a check of the energy conservation property as a means of verifying the quality of the numerical simulation. Due to an optimized loading technique, the conservation property is satisfied with an unprecedented quality well into the nonlinear stage. The zonal component of the perturbation evolves to a quasi-steady state with regions of ITG suppression, strongly reduced radial energy flux and steepened effective temperature profiles alternating with regions of higher ITG mode amplitudes, larger radial energy flux and flattened effective temperature profiles. A semi-Lagrangian approach free of statistical noise is proposed as an alternative to the nonlinear Delta f formulation. An ASDEX-Upgrade experiment with an internal transport barrier is analysed with a global gyrokinetic code that includes trapped electron dynamics. The weakly destabilizing effect of trapped electron dynamics on ITG modes in an axisymmetric bumpy configuration modelling W7-X is shown in global linear simulations that retain the full electron dynamics. Finite Delta effects on microinstabilities are investigated with a linear global spectral electromagnetic gyrokinetic formulation. The radial global structure of electromagnetic modes shows a resonant behaviour with rational q values.

Additional information

Authors: VILLARD L, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne, Euratom-Suisse, Lausanne (CH);ALLFREY S, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne, Euratom-Suisse, Lausanne (CH);BOTTINO A, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne, Euratom-Suisse, Lausanne (CH);BRUNETTI M, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne, Euratom-Suisse, Lausanne (CH);SAUTER O, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne, Euratom-Suisse, Lausanne (CH);VACLAVIK J, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne, Euratom-Suisse, Lausanne (CH);FALCHETTO G, Departement de Recherches sur la Fusion Controlee, Euratom-CEA, Cadarache (FR);GRANDGIRARD V, Departement de Recherches sur la Fusion Controlee, Euratom-CEA, Cadarache (FR);HATZKY R, Rechenzentrum der Max-Planck Gesellschaft, Garching (DE);NUHRENBERG J, Max-Planck Institut fur Plasmaphysik, Euratom-IPP, Greifswald (DE);NÜHRENBERG J, Max-Planck Institut für Plasmaphysik, Euratom-IPP, Greifswald (DE);SORGE S, Max-Planck Institut für Plasmaphysik, Euratom-IPP, Greifswald (DE);PEETERS A, Max-Planck Institut für Plasmaphysik, Euratom-IPP, Garching (DE)
Bibliographic Reference: Article published in: Nuclear Fusion , vol.44 (2004) pp.172-180
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://pub.iaea.org/MTCD/NF/NFusion.asp
Record Number: 200417376 / Last updated on: 2004-02-02
Category: PUBLICATION
Original language: en
Available languages: en
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