A 3D approach to equilibrium, stability and transport studies in RFX-mod improved regimes

Journal Article · Fri Jan 01 00:00:00 EST 2010 · Plasma Physics and Controlled Fusion

DOI:https://doi.org/10.1088/0741-3335/52/12/124023· OSTI ID:1019381

Terranova, D ^[1]; Bonfiglio, D ^[1]; Boozer, A H ^[2]; Cooper, W Anthony ^[3]; Gobbin, M ^[1]; Hirshman, Steven Paul ^[4]; Lorenzini, R ^[1]; Marrelli, L ^[1]; Martines, E ^[5]; Momo, B ^[5]; Pomphrey, N ^[6]; Predebon, I ^[5]; Sanchez, Raul ^[4]; Spizzo, G ^[1]; Agnostini, M ^[1]; Alfier, A ^[1]; Apolloni, L ^[1]; Auriemma, F ^[1]; Baruzzo, M ^[1]; Bolzonella, T ^[1] ; Bonomo, F ^[7]; Brombin, M ^[1]; Canton, A ^[1]; Cappello, S ^[1]; Carraro, L ^[1]

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1. Association Euratom ENEA Fusion, Consorzio RFX, Padua
2. Columbia University
3. CRPP/EPFL, Association Euratom-Suisse, Lausanne, Switzerland
4. ORNL
5. RFX, Padova, Italy
6. Princeton Plasma Physics Laboratory (PPPL)
7. Consorzio RFX, Italy

The full three-dimensional (3D) approach is now becoming an important issue for all magnetic confinement configurations. It is a necessary condition for the stellarator but also the tokamak and the reversed field pinch (RFP) now cannot be completely described in an axisymmetric framework. For the RFP the observation of self-sustained helical configurations with improved plasma performances require a better description in order to assess a new view on this configuration. In this new framework plasma configuration studies for RFX-mod have been considered both with tools developed for the RFP as well as considering codes originally developed for the stellarator and adapted to the RFP. These helical states are reached through a transition to a very low/reversed shear configuration leading to internal electron transport barriers. These states are interrupted by MHD reconnection events and the large T(e) gradients at the barriers indicate that both current and pressure driven modes are to be considered. Furthermore the typically flat T(e) profiles in the helical core have raised the issue of the role of electrostatic and electromagnetic turbulence in these reduced chaos regions, so that a stability analysis in the correct 3D geometry is required to address an optimization of the plasma setup. In this view the VMEC code proved to be an effective way to obtain helical equilibria to be studied in terms of stability and transport with a suite of well tested codes. In this work, the equilibrium reconstruction technique as well as the experimental evidence of 3D effects and their first interpretation in terms of stability and transport are presented using both RFP and stellarator tools.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1019381
• Journal Information: Plasma Physics and Controlled Fusion, Vol. 52, Issue 12; ISSN 0741--3335
• Country of Publication: United States
• Language: English

Related Subjects

REVERSED-FIELD PINCH
TOROIDAL PLASMAS
COEFFICIENTS
CONFINEMENT
EVOLUTION