Plasma Shape Effects on Geodesic Acoustic Oscillations

Journal Article · Thu Nov 30 04:00:00 EST 2006 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2404581· OSTI ID:20895156

Villard, L; Angelino, P; Jolliet, S; McMillan, B F; Sauter, O; Tran, T M ^[1]; Bottino, A ^[2]; Hatzky, R ^[3]; Max-Planck Gesellschaft, D-85748 Garching ^[4]

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1. Centre de Recherches en Physique des Plasmas, Association Euratom -- Confederation Suisse, EPFL, 1015 Lausanne (Switzerland)
2. Max-Planck Gesellschaft Institute for Plasma Physics, D-85748 Garching (Germany)
3. Computer Center of the IPP, D-85748 Garching (Germany)
4. Germany

Geodesic acoustic mode (GAM) oscillations in tokamak plasmas are known to be sensitive to the value of the safety factor q. Through its linear and nonlinear interactions with ITG turbulence it has recently been shown in direct numerical global simulations that the turbulence driven heat transport is larger when GAM oscilations of large amplitude are present, resulting in an anomalous transport scaling with the inverse plasma current. GAM dispersion relations have been derived for circular, large aspect ratio configurations, and, recently, for helical configurations. Linear simulation results are presented using the global, PIC, finite element codes GYGLES and ORB5 for the GAM frequency, damping rate and Rosenbluth-Hinton residual zonal flow for a scan in plasma elongation. It is found that CAM frequency slightly decreases, while GAM damping rate and residual zonal flows increase with elongation. Nonlinear ITG simulations using the ORB5 code show that elongation reduces heat transport and that this is related to the plasma current and not q alone.

• OSTI ID: 20895156
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 871; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ASPECT RATIO
DISPERSION RELATIONS
FINITE ELEMENT METHOD
G CODES
HEAT TRANSFER
HELICAL CONFIGURATION
NONLINEAR PROBLEMS
O CODES
OSCILLATIONS
PLASMA
PLASMA INSTABILITY
PLASMA SIMULATION
PLASMA WAVES
TOKAMAK DEVICES
TURBULENCE