Abstract
We investigate zonal flow (ZF) generation in ion temperature gradient driven trapped-electron-mode (ITG-driven TEM) turbulence via modulational instability analysis. We show that the acceleration of a seed ZF is a consequence of the competition of negative radiation pressure (NRP, acting as a driving force) and positive radiation pressure (PRP, acting as a retarding force) of the ITG-driven TEM turbulence. A critical dimensionless ion temperature logarithmic gradient () normalized to the major radius is obtained by balancing the NRP- and PRP effects. For , the NRP effect is dominant and the seed ZF is accelerated. Otherwise, the PRP effect is dominant and the seed ZF is decelerated. In addition, a new nonlinear evolution mechanism of the ZF is also proposed. It is shown that the turbulence energy intensity spectrum gets steepened in k-space due to the ZF shearing, which in turn induces nonlinear growth of the ZF.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
