Observation of magnetic islands in tokamak plasmas during the suppression of edge-localized modes

the ASDEX Upgrade Team

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

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.

Original languageEnglish
JournalNature Physics
DOIs
StateAccepted/In press - 2024

Funding

We are grateful to C. Paz-Soldan, E. Poli, Q. Yu and H. Zohm for fruitful discussions. This material is based upon work supported by the US Department of Energy under award DE-SC0021968. This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (grant agreement no. 101052200-EUROfusion). Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them.

Fingerprint

Dive into the research topics of 'Observation of magnetic islands in tokamak plasmas during the suppression of edge-localized modes'. Together they form a unique fingerprint.

Cite this