Influence of plasma boundary shape on helical core/long-lived mode in tokamak plasmas

Helical distortion of the core part of tokamak plasma, which is called a helical core or a long-lived mode, is investigated by means of three-dimensional magnetohydrodynamic equilibrium calculations. It is found that the magnitude of the helical distortion strongly depends on the shape of the plasma...

Full description

Saved in:
Bibliographic Details
Published in:Physics of plasmas 2020-09, Vol.27 (9)
Main Authors: Nakamura, Y., Ishizawa, A., Ishida, Y.
Format: Article
Language:English
Subjects:
Amplitudes
Distortion
Ellipticity
Fluid flow
Magnetohydrodynamics
Plasma physics
Plasmas (physics)
Tokamak devices
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Helical distortion of the core part of tokamak plasma, which is called a helical core or a long-lived mode, is investigated by means of three-dimensional magnetohydrodynamic equilibrium calculations. It is found that the magnitude of the helical distortion strongly depends on the shape of the plasma boundary for weakly reversed shear plasmas. The triangularity of the boundary enhances the amplitude of helical distortion. In addition, reversed D-shape plasmas also exhibit a helical core. It is also found that the triangularity lowers the critical β for the onset of a helical core; furthermore, the critical β vanishes when the triangularity exceeds a certain value. On the other hand, the influence of the ellipticity on the amplitude of helical distortion strongly depends on β. The ellipticity enhances the amplitude at high β, while it reduces the amplitude at low β.
ISSN:1070-664X
1089-7674
DOI:10.1063/5.0013652