Nuclear Fusion (Jan 2023)

Experimentally corroborated model of pressure relaxation limit cycle oscillations in the vicinity of the transition to high confinement in tokamaks

  • O. Grover,
  • P. Manz,
  • A.Y. Yashin,
  • D.I. Réfy,
  • J. Seidl,
  • N. Vianello,
  • G. Birkenmeier,
  • E.R. Solano,
  • M. Sos,
  • P. Bohm,
  • P. Bilkova,
  • M. Hron,
  • R. Panek,
  • the ASDEX Upgrade Team,
  • the COMPASS Team,
  • the Globus-M Team,
  • JET Contributors

DOI
https://doi.org/10.1088/1741-4326/ad0eae
Journal volume & issue
Vol. 64, no. 2
p. 026001

Abstract

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An analytical formula systematically predicts the observed frequency of pressure relaxation limit cycle oscillations in the vicinity of the transition to high confinement in four tokamaks (JET, ASDEX Upgrade, COMPASS, Globus-M). The experimental dataset spans the widest available range of frequencies, machine sizes and plasma ion species. The machine size dependence is explained by the connection length scale of plasma flows parallel to the magnetic field. The model also explains the observed up-down poloidal current asymmetry and the impact of the plasma ion species mass and charge.

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