Saturation of magnetized plasma turbulence by propagating zonal flows
Abstract
Strongly driven ion-scale turbulence in tokamak plasmas is shown to be regulated by a new propagating zonal flow mode, the toroidal secondary mode, which is nonlinearly supported by the turbulence. The mode grows and propagates due to the combined effects of zonal flow shearing and advection by the magnetic drift. Above a threshold in the turbulence level, small-scale toroidal secondary modes become unstable and shear apart turbulent eddies, forcing the turbulence level to remain near the threshold. This threshold condition is used to derive scaling laws for the turbulent heat flux, fluctuation spectra, and zonal flow amplitude, which are validated in nonlinear gyrokinetic simulations and explain previous experimental observations.
Fields of Study & Subjects
Solar and Space Plasma Dynamics
Magnetic confinement fusion research
Publication details
- Journal / source
- Physical Review Research
- Publisher
- American Physical Society (APS)
- Volume
- 8
- Issue
- 1
- Publication date
- 11 February 2026
- Language
- EN