Sherwood 2015

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The effect of strong toroidal flow shear on MHD equilibrium in a tokamak

Author: Jungpyo Lee
Requested Type: Poster Only
Submitted: 2015-01-19 20:33:57

Co-authors: A.Cerfon

Contact Info:
251 Mercer street #1008
New York, NY   10012

Abstract Text:
Ion toroidal rotation is often observed in a tokamak and it is beneficial to regulate macroscopic and microscopic turbulences. We investigate how the rotation changes the MHD equilibrium of a tokamak and how the changes in the equilibrium affect the macroscopic and microscopic turbulences. A MHD equilibrium code, ECOM, is used to evaluate the axisymmetric equilibrium in the presence of the toroidal flow with a predefined radial profile of either the poloidal current, the parallel current, or the safety factor. Here, we focus on the equilibrium for the localized strong toroidal flow that has an inertial force due to the flow as strong as the kinetic pressure force without the flow. For this strong flow shear, we found that the safety factor profile can be reversed if the poloidal current or the parallel current is constrained. If the safety factor is constrained as the momentum injection does not change magnetic fluxes, the flow shear changes the local magnetic shear significantly. As a consequence of the changes in the local magnetic shear, the s-alpha diagram for MHD Ballooning instability changes significantly.

This paper is for the topic, "Plasma Properties, Equilibrium, Stability, and Transport".

March 16-18, 2015
The Courant Institute, New York University