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arXiv · 2501.02960

Geometric curvature effect on suppressing the Ion-Temperature-Gradient mode near the magnetic axis

Tiannan Wu·Shaojie Wang
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Abstract

Global gyrokinetic simulation of the ion temperature gradient mode shows that the radial electric field ($E_r$) well upshifts the critical temperature gradient near the magnetic axis, in the weak but not in the strong magnetic shear configuration. The geometric curvature effect significantly influences the $E \times B$ shear and the wave number near the axis, so that the $E_r$ well suppresses the high-n modes but has little effect on the low-n modes, which are suppressed by the weak magnetic shear effect. This new finding unravels the formation mechanism of the internal transport barrier in the weak central magnetic shear discharges.

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Tiannan Wu, Shaojie Wang. 2025-01-06. Geometric curvature effect on suppressing the Ion-Temperature-Gradient mode near the magnetic axis. https://arxiv.org/abs/2501.02960

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