Enhancement of residual stress by electromagnetic fluctuations: A quasi-linear study

A study is conducted on the impact of electromagnetic (EM) fluctuations on residual Reynolds stress in the context of the quasi-linear theory. We employ a fluid formulation describing EM ion temperature gradient turbulence. Analyses show that finite plasma beta (=plasma thermal energy/magnetic energy) significantly increases the residual stress, potentially leading to the strong enhancement of flow generation in high beta plasmas. We identify that this strong increase of residual stress originates from the reinforcement of radial < k(parallel to)> (=spectrally averaged parallel wavenumber) asymmetry due to the deformation of eigenfunctions near a rational surface. Published by AIP Publishing.