Abstract Details
Abstracts
Author: Miura Hideaki
Requested Type: Poster
Submitted: 2019-02-21 01:06:41
Co-authors: L.Zheng, W.Horton
Contact Info:
National Institute for Fusion Science
322-6 Oroshi-cho
Toki, Gifu 509-529
日本
Abstract Text:
Numerical simulations of interchange/tearing instabilities (Current-Interchange Tearing Modes, CITM) with two-fluid (Hall) and gyro-viscous (Finite Larmore Radius, FLR) in a 2D slab for edge plasma resistivity are carried out. The current diffusivity model which has been developed by the authors [Phys. Plasmas 2017] to represent effects of stochastic magnetic field lines is adopted in this simulation research. The sub-grid-model developed by one of the authors (HM) to represent influences of the scales smaller than the grid width to the scales larger than the grid width is also adopted.
In the previous work by the authors (Sherwood 2018), diamagnetic flow appears due to the two-fluid and gyro-viscous terms. The diamagnetic flow is found to interact with the CITM. The CITM often survives the nonlinear interaction with the diamagnetic flow and transit to tearing mode even though the interaction makes interchange-like aspects of the CITM very ambiguous.
In this work, we revisit this behavior from a point of views of the ambient flow field. We study the interaction between the CITM, the diamagnetic flow and the flow driven at the boundary wall (as a model of the flow in the plasma core). We show that that the plasma-core-side and peripheral regions can be turbulent while the flow in the edge region is relatively laminar when the externally-imposed (ambient) flow is relatively fast. On the other hand, only the plasma peripheral regions can become turbulent when the ambient flow is very weak. These simulations show that appearance of turbulence due to the ambient flow field is quite case-sensitive, and sometimes can suppress heat transport associated with the nonlinear growth of CITM.
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