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Abstract

Transport barriers at the plasma edge are key elements of high confinement regimes in fusion devices. In typical configurations, such barriers are not stable but exhibit quasi-periodic relaxation oscillations. In this work, one-dimensional and zero-dimensional models for such oscillations are presented that give insight into the underlying mechanisms which are found to be intrinsically nonlinear. The models are systematically derived from three-dimensional turbulence simulations based on a fluid description of the plasma. In these simulations, a transport barrier is generated by an imposed E x B shear flow. This barrier exhibits quasiperiodic relaxation oscillations even if the E x B shear flow is frozen. The models presented here are therefore different from those based on turbulent shear flow generation. They allow to isolate and illustrate a different mechanism for barrier oscillations. Furthermore, these models reproduce regimes characterized by a decrease of the oscillation frequency with the E x B flow shear.

Additional information

Authors: FUHR G, Laboratoire PIIM, CNRS - Université de Provence, Centre de St Jérôme, Case 321, Marscille (FR);BENKADDA S, Laboratoire PIIM, CNRS - Université de Provence, Centre de St Jérôme, Case 321, Marscille (FR);BEYER P, Laboratoire PIIM, CNRS - Université de Provence, Centre de St Jérôme, Case 321, Marscille (FR);GARBET X, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);GHENDRIH P, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);SARAZIN Y, Département de Recherches sur la Fusion Contrôlée, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR)
Bibliographic Reference: An article published in: Journal of Physics: Conference Series 7 (2005), pp. 227-232
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://dx.doi.org/10.1088/1742-6596/7/1/019
Record Number: 200719071 / Last updated on: 2007-04-11
Category: PUBLICATION
Original language: en
Available languages: en