Nonlinear Dynamics of Transport Barrier Relaxations in Fusion Plasmas
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چکیده
Relaxation oscillations of transport barriers are studied by three dimensional turbulence simulations. Barriers generated by an imposed ExB shear flow are found to relax intermittently on confinement time scales, even when fluctuations of the ExB shear flow are suppressed. A relaxation event has a complex dynamical behavior, characterized by the intermittent growth of a mode at the barrier center. An analytical study reveals that this dynamics is governed by the ExB velocity shear. A crucial ingredient therein is a time delay for effective ExB velocity shear stabilization.
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تاریخ انتشار 2004