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Turbulent Nature of the Quasicontinuous Exhaust Regime for Fusion Plasmas

Kaiyu Zhang*, Wladimir Zholobenko, Andreas Stegmeir, Michael Faitsch, Konrad Eder, Christoph Pitzal, Frank Jenko, and ASDEX Upgrade Team†

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Phys. Rev. Lett. 137, 055102 – Published 30 July, 2026

DOI: https://doi.org/10.1103/j44y-5dp6

Abstract

We demonstrate a turbulence mechanism that reconciles high plasma confinement with efficient heat exhaust—a central challenge for fusion energy. Global two-fluid turbulence simulations of the reactor-relevant quasicontinuous exhaust regime on the ASDEX Upgrade tokamak reveal that a quasicoherent mode drives mesoscopic oscillations of the pedestal boundary across the magnetic separatrix and ejects ballistic filaments (blobs), reproducing both the mean profiles and turbulent fluctuations observed experimentally. This behavior arises from a synergistic interplay between kinetic ballooning modes and resistive X-point modes straddling the separatrix. These first-principles results place extrapolations to future fusion reactors on a firm physical footing.

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Tapping Tokamak Turbulence

Published 30 July, 2026

Supercomputer simulations reveal how turbulence supports a Goldilocks regime for operating a fusion reactor.

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Phys. Rev. Lett. 137, 055102– Published 30 July, 2026
  • Received 2 March 2026
  • Accepted 3 June 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Open access publication funded by the Max Planck Society.

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