Criteria for the importance of multi-scale interactions in turbulent transport simulations. (25th June 2019)

• Record Type: Journal Article
• Authors: Creely, A J; Rodriguez-Fernandez, P; Conway, G D; Freethy, S J; Howard, N T; White, A E
• Other Names: collab.
• Is Part Of: Plasma physics and controlled fusion. Volume 61:Number 8(2019)
• Publication Date: 2019-06-25
• Subjects: turbulence -- validation -- multi-scale -- perturbative diffusivity -- temperature fluctuations; Plasma (Ionized gases) -- Periodicals; Controlled fusion -- Periodicals; 530.44
• DOI: 10.1088/1361-6587/ab24ae
• Languages: English
• ISSNs: 0741-3335

Abstract

Abstract: Turbulent transport simulations have been used to develop criteria that indicate when multi-scale turbulent phenomena are important in tokamak plasmas. Twelve experimental plasma discharges from the Alcator C-Mod and ASDEX Upgrade tokamaks are compared to ion- and multi-scale simulations with the Trapped Gyro-Landau Fluid (TGLF) turbulence code. Multi-scale TGLF agrees with all available validation constraints (ion heat flux, electron heat flux, electron temperature fluctuations, and electron perturbative thermal diffusivity) within uncertainty for all cases analyzed. Ion-scale TGLF agrees in only some cases. Two criteria based on the ratios of normalized linear growth rates are able to distinguish cases in which ion-scale simulations are sufficient from cases for which multi-scale simulations are necessary. The form of these criteria reveal the key role of zonal flow mixing in moderating multi-scale effects.