Volume 116, Number 1, October 2016
|Number of page(s)||5|
|Section||Physics of Gases, Plasmas and Electric Discharges|
|Published online||18 November 2016|
Roles of turbulence– and pressure-gradient–induced flows in triggering H-mode at marginal heating power on HL-2A tokamak
1 Southwestern Institute of Physics - P. O. Box 432, Chengdu, Sichuan 610041, China
2 Institute for Fusion Theory and Simulation, Zhejiang University - Hangzhou 310027, China
3 CEA, IRFM - F-13108 Saint-Paul-lez-Durance, France
Received: 27 July 2016
Accepted: 24 October 2016
A qualitative model which includes three loops of zonal flow vs. turbulence and turbulence vs. pressure gradient is proposed for the experimentally observed two types of limit cycle oscillations (LCOs) and low-intermediate-high (L-I-H) confinement transitions. The experimental evidences supporting the model and revealing the roles of turbulence– and pressure-gradient–induced flows in triggering the H-mode at marginal heating power in tokamak plasmas are presented. The dominant role played by pressure-gradient–induced flows in I-phase of type-J LCO as well as I-H transition is demonstrated, along with that done by the turbulent-Reynolds-stress–driven zonal flows in the L-I transition as well as I-phase of type-Y LCO. The trigger and conditions for the I-H transition are identified from the experimental observations.
PACS: 52.35.Ra – Plasma turbulence / 52.30.-q – Plasma dynamics and flow / 52.25.Fi – Transport properties
© EPLA, 2016
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