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  • Letter
  • Open Access

Role of isotopes in microturbulence from linear to saturated Ohmic confinement regimes

Lei Qi*, Jae-Min Kwon, T. S. Hahm, M. Leconte, Sumin Yi, Y. W. Cho, and Janghoon Seo

  • Korea Institute of Fusion Energy, Daejeon 169-148, South Korea

  • *qileister@kfe.re.kr
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Phys. Rev. Research 6, L012004 – Published 8 January, 2024

DOI: https://doi.org/10.1103/PhysRevResearch.6.L012004

Abstract

The first-principle gyrokinetic numerical experiments investigating the isotopic dependence of energy confinement achieve a quantitative agreement with experimental empirical scalings, particularly in Ohmic and L-mode tokamak plasmas. Mitigation of turbulence radial electric field intensity |δEr|2 and associated poloidal δE×B fluctuating velocity with the radial correlation length lcr∝Mi0.11 strongly deviating from the gyro-Bohm scaling is identified as the principal mechanism behind the isotope effects. Three primary contributors are classified: the deviation from gyro-Bohm scaling, zonal flow, and trapped electron turbulence stabilization. Zonal flow enhances isotope effects primarily through reinforcing the inverse dependence of turbulence decorrelation rate on isotope mass with ωc∝Mi−0.76, which markedly differs from the characteristic linear frequency. The findings offer insights into isotope effects, providing critical implications for energy confinement optimization in tokamak plasmas.

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Outline

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Phys. Rev. Research 6, L012004– Published 8 January, 2024
  • Received 25 April 2023
  • Accepted 27 November 2023
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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.

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