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Title: Radial convection of finite ion temperature, high amplitude plasma blobs

We present results from simulations of seeded blob convection in the scrape-off-layer of magnetically confined fusion plasmas. We consistently incorporate high fluctuation amplitude levels and finite Larmor radius (FLR) effects using a fully nonlinear global gyrofluid model. This is in line with conditions found in tokamak scrape-off-layers (SOL) regions. Varying the ion temperature, the initial blob width, and the initial amplitude, we found an FLR dominated regime where the blob behavior is significantly different from what is predicted by cold-ion models. The transition to this regime is very well described by the ratio of the ion gyroradius to the characteristic gradient scale length of the blob. We compare the global gyrofluid model with a partly linearized local model. For low ion temperatures, we find that simulations of the global model show more coherent blobs with an increased cross-field transport compared to blobs simulated with the local model. The maximal blob amplitude is significantly higher in the global simulations than in the local ones. When the ion temperature is comparable to the electron temperature, global blob simulations show a reduced blob coherence and a decreased cross-field transport in comparison with local blob simulations.
Authors:
;  [1] ;  [2]
  1. Institute for Ion Physics and Applied Physics, Association EURATOM-ÖAW, University of Innsbruck, A-6020 Innsbruck (Austria)
  2. Association EURATOM-DTU, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark)
Publication Date:
OSTI Identifier:
22303625
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 9; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AMPLITUDES; COMPARATIVE EVALUATIONS; CONVECTION; ELECTRON TEMPERATURE; FLUCTUATIONS; ION TEMPERATURE; LARMOR RADIUS; NONLINEAR PROBLEMS; PLASMA; PLASMA SCRAPE-OFF LAYER; SIMULATION; TOKAMAK DEVICES