Work

Gyrokinetic simulations of turbulence-driven magnetic islands in toroidal geometry

Year: 2026

Type: article

Abstract: We report a universal mechanism for turbulence-driven magnetic islands in fusion plasmas that operates independently of the parity of the destabilizing micro-instability. Using gyrokinetic simulations of a linearly stable tearing mode in a large-aspect-ratio toroidal geometry under collisionless conditions, we demonstrate that micro-instabilities generate an E×B flow that is consistent with magnetic field line reconnection. This process forms multiple small-scale islands along the resonant surface, which interact non-linearly and eventually coalesce into large-scale magnetic islands. These islands are capable of significantly flattening the equilibrium profile across the island O-points and can potentially act as a seed for further neoclassical growth. Notably, the mechanism operates independently of the parity of the destabilizing micro-instability.

Source: Physics of Plasmas

DOI: 10.1063/5.0314332

Authors: F. Widmer, E. Poli, A. Mishchenko, A. Ishizawa, T. Hayward-Schneider, A. Bottino

Institutions: Max Planck Institute for Plasma Physics, Max Planck Institute for Plasma Physics - Greifswald, Kyoto University

Language: English

Topic: Magnetic confinement fusion research

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funder: EUROfusion

Awards: G3562821882, G7464272566, G806595050