Observation of magnetic islands in tokamak plasmas during the suppression of edge-localized modes
Artikel i vetenskaplig tidskrift, 2024

In tokamaks, a leading platform for fusion energy, periodic filamentary plasma eruptions known as edge-localized modes occur in plasmas with high-energy confinement and steep pressure profiles at the plasma edge. These edge-localized modes could damage the tokamak wall but can be suppressed using small three-dimensional magnetic perturbations. Here we demonstrate that these magnetic perturbations can change the magnetic topology just inside the steep gradient region of the plasma edge. We identify signatures of a magnetic island, and their observation is linked to the suppression of edge-localized modes. We compare high-resolution measurements of perturbed magnetic surfaces with predictions from ideal magnetohydrodynamic theory where the magnetic topology is preserved. Although ideal magnetohydrodynamics adequately describes the measurements in plasmas exhibiting edge-localized modes, it proves insufficient for plasmas where these modes are suppressed. Nonlinear resistive magnetohydrodynamic modelling supports this observation. Our study experimentally confirms the predicted role of magnetic islands in inhibiting the occurrence of edge-localized modes. This will be beneficial for physics-based predictions in future fusion devices to control these modes.
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Publicerad i

Nature Physics

1745-2473 (ISSN) 17452481 (eISSN)

Vol. 20 Nummer/häfte 12 s. 1980-1988

Forskningsprojekt

Implementation of activities described in the Roadmap to Fusion during Horizon Europe through a joint programme of the members of the EUROfusion consortium

Europeiska kommissionen (EU) (101052200), 2021-01-01 -- 2025-12-31.

Kategorisering

Ämneskategorier (SSIF 2011)

Fusion, plasma och rymdfysik

Identifikatorer

DOI

10.1038/s41567-024-02666-y

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Senast uppdaterat

2025-03-17