Nonlinear equilibria, stability and generation of zonal structures in toroidal plasmas
- University of California, Irvine
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.
- Research Organization:
- Univ. of California, Irvine, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
- DOE Contract Number:
- FG02-04ER54736
- OSTI ID:
- 1130345
- Report Number(s):
- DOE-UCI-ER54736
- Journal Information:
- Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 8 Vol. 47; ISSN 0029-5515
- Publisher:
- IOP Science
- Country of Publication:
- United States
- Language:
- English
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