The long-lived saturated zonal flow (ZF) structures, spontaneously generated by drift-wave (DW) turbulence, are viewed as generators of nonlinear equilibria. Here, we derive a nonlinear evolution equation for the zonal response, valid for arbitrary wavelengths, whose time-asymptotic behaviour corresponds to the nonlinear equilibrium. Its corresponding stability, meanwhile, determines the nature of the ZF instability and the nonlinear up-shift of turbulent transport thresholds. On a shorter-time scale, the temporal evolution of the zonal response describes the DW-ZF generation and the regulation of the DW intensity by the ZFs. As an application, we present a kinetic stability analysis of zonal structures in the ion temperature gradient driven DW turbulence case as well as the corresponding collisionless zonal dissipation rates. © 2007 IAEA.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Condensed Matter Physics
- Nuclear and High Energy Physics
Chen, L., & Zonca, F. (2007). Nonlinear equilibria, stability and generation of zonal structures in toroidal plasmas. Nuclear Fusion, 47(8), 886 - 891. . https://doi.org/10.1088/0029-5515/47/8/021