Kim EJ, Diamond PH. Zonal flows and transient dynamics of the L-H transition.
PHYSICAL REVIEW LETTERS 2003;
90:185006. [PMID:
12786016 DOI:
10.1103/physrevlett.90.185006]
[Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2003] [Indexed: 05/24/2023]
Abstract
We elucidate the role of zonal flows in transient phenomena observed during L-H transition by studying a simple L-H transition model which contains the evolution of zonal flows, mean ExB flows, and the ion pressure gradient. Zonal flows are shown to trigger the L-H transition and cause time-transient behavior through the self-regulation of turbulence before a mean shearing, due to a steep pressure profile, secures a quiescent H mode. Surprisingly, this self-regulation lowers the power threshold for the ultimate transition to a quiescent H-mode state.
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