Shear flow generation from the interaction of neoclassical and drift wave transport processes
Self-consistent shear flow generation from the interaction of neoclassical and drift wave turbulence effects is investigated. The neoclassical poloidal flow damping is shown to compete with the flow generation driven by the divergence of the Reynolds stress. When there is no external driving force except for the free energy released from toroidal shear flow, the turbulent fluctuations occur as a transient pulse which takes the system along an equilibrium path to a relaxed state. External torques, such as parallel neutral beam injection, are needed to maintain significant fluctuation levels. For a system driven by a fixed ion temperature gradient, although linearly the poloidal shear flow generated substantially reduces the growth rate, the simulation results show that a sequence of nonlinear pulses occurs that eventually build the fluctuations up to a level that is not significantly affected by the poloidal flow. In this new, highly nonlinear state the transport is intermittent occurring through a sequence of pulses of duration 100 L{sub n}/c{sub s} for typical parameters.
- Research Organization:
- Univ. of Texas, Austin, TX (United States). Institute for Fusion Studies
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG05-80ET53088
- OSTI ID:
- 10105273
- Report Number(s):
- DOE/ET/53088-T4; ON: DE94003135; BR: 39KG01000/AT0520240; TRN: 94:001361
- Resource Relation:
- Other Information: PBD: Oct 1993
- Country of Publication:
- United States
- Language:
- English
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