Abstract Details
Abstracts
Author: Hideaki Miura
Requested Type: Pre-Selected Invited
Submitted: 2019-02-18 10:43:56
Co-authors: Linjin Zheng, Wendell Horton
Contact Info:
University of Texas at Austin
6501 Mesa Dr
Austin, TX 78712
United States
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.
Comments:
First author Prof Hideaki Miura is applying to travel from Japan to Conference but in the event he is unable to travel Prof Horton will give the talk.
