Global gyrokinetic simulations of the impact of magnetic island on ion temperature gradient driven turbulence

Li，Jingchun1; Xu，J. Q.2; Qu，Y. R.3; Lin，Z.4; Dong，J. Q.2,5; Peng，X. D.2; Li，J. Q.2

2023-09-01

10.1088/1741-4326/ace461

Nuclear Fusion   Impact Factor & Quartile

0029-5515

1741-4326

The effect of island width on the multi-scale interactions between magnetic island (MI) and ion temperature gradient (ITG) turbulence has been investigated based on the global gyrokinetic approach. It is found that the coupling between the island and turbulence is enhanced when the MI width (w) becomes larger. A vortex flow that is highly sensitive to the width of the MI can be triggered, ultimately resulting in a potent E × B shear flow and a consequent reduction in turbulent transport. The shearing rate induced by the vortex flow is minimum at the O-point while it is maximum at both of the two reconnection points of the island, i.e. the X-points, regardless of the island width. There exists a nonmonotonic relationship between zonal flow (ZF) amplitude and island width, showing that the ZF is partially suppressed by medium-sized MIs whereas enhanced in the case of large island. A larger MI can tremendously damage the ITG mode structure, resulting in higher turbulent transport at the X-point whereas a lower one at the O-point, respectively. Such phenomenon will be less distinct at very small island widths below w/a ∼ 8% ≈ 12 ρ i (a is the minor radius and ρ i the ion gyroradius), where it shows that turbulence near the X-point is hardly affected although it is still suppressed inside the island. Furthermore, the influence of different island sizes on turbulence transport level is also discussed.

gyrokinetic simulation ITG mode magntic island turbulence vortex flow

SCI

English

First ; Corresponding

WOS:001039584100001

PHYSICS

2-s2.0-85166472256

Scopus

1.Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen,Guangdong,518055,China
2.Southwestern Institute of Physics,Chengdu,PO Box 432,610041,China
3.School of Physics,Nankai University,Tianjin,300071,China
4.University of California,Irvine,92697,United States
5.ENN Science and Technology Development Co.,Ltd,Langfang,065001,China

Li，Jingchun,Xu，J. Q.,Qu，Y. R.,et al. Global gyrokinetic simulations of the impact of magnetic island on ion temperature gradient driven turbulence[J]. Nuclear Fusion,2023,63(9).

Li，Jingchun.,Xu，J. Q..,Qu，Y. R..,Lin，Z..,Dong，J. Q..,...&Li，J. Q..(2023).Global gyrokinetic simulations of the impact of magnetic island on ion temperature gradient driven turbulence.Nuclear Fusion,63(9).

Li，Jingchun,et al."Global gyrokinetic simulations of the impact of magnetic island on ion temperature gradient driven turbulence".Nuclear Fusion 63.9(2023).