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DOE OSTI · 1764129

Anisotropic E × B shearing rate in a magnetic island

Hahm, T. S.·Kim, Y. J.·Diamond, P. H.·Choi, G. J.
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Abstract

We derive the E × B shearing rate associated with vortex flow inside a macroscopic magnetic island (MI) in axisymmetric toroidal geometry. Due to the elongation of the MI and incompressibility of the E × B flow, the shearing rate near X-points is much lower than that near the mid-plane (x-axis of the local Cartesian coordinate) of the MI on the same flux surface. Furthermore, the rate formally vanishes at the X-points where the local poloidal magnetic field associated with the MI stagnates. Here, this calculation of E × B shearing profile and, in particular, minimal E × B shear near the X-points is consistent with the recent experimental finding that turbulence tends to spread into an MI through regions around the X-points and can contribute to more thorough quantitative interpretation of the results from experiments and simulations.

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70 PLASMA PHYSICS AND FUSION TECHNOLOGYTurbulent flowsgyrokinetic simulationsplasma confinementtokamaks

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Hahm, T. S., Kim, Y. J., Diamond, P. H., Choi, G. J.. 2021-02-02. Anisotropic E × B shearing rate in a magnetic island. https://doi.org/10.1063/5.0036583

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