TY - JOUR
T1 - Zero-dimensional model for the critical condition for the L-H transition in the flux-gradient relation
AU - Itoh, S. I.
AU - Itoh, K.
N1 - Publisher Copyright:
© 2014 IAEA, Vienna.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2014/10/1
Y1 - 2014/10/1
N2 - In this paper, the physics of the L- to H-mode transition is discussed, focusing on the mechanism induced by the localized mean radial electric field. In addition to the neoclassical effect, an additional source of the electric field is introduced. The influence of turbulence-driven Reynolds stress is taken into account here. The case where the zonal flows are not excited is analysed. Even if the spontaneous zonal flows by turbulence cannot be excited, the bifurcation of the mean radial electric field can occur, if the electric field is strong enough eρpEr/Ti∼-1. Hard transition of the electric field takes place. The enhancement of electric field above this critical value can induce a bifurcation in the gradient-flux relation, i.e. the disappearance of the L-mode branch. The critical condition of the heat flux for the onset of transition is obtained.
AB - In this paper, the physics of the L- to H-mode transition is discussed, focusing on the mechanism induced by the localized mean radial electric field. In addition to the neoclassical effect, an additional source of the electric field is introduced. The influence of turbulence-driven Reynolds stress is taken into account here. The case where the zonal flows are not excited is analysed. Even if the spontaneous zonal flows by turbulence cannot be excited, the bifurcation of the mean radial electric field can occur, if the electric field is strong enough eρpEr/Ti∼-1. Hard transition of the electric field takes place. The enhancement of electric field above this critical value can induce a bifurcation in the gradient-flux relation, i.e. the disappearance of the L-mode branch. The critical condition of the heat flux for the onset of transition is obtained.
UR - http://www.scopus.com/inward/record.url?scp=84908546280&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84908546280&partnerID=8YFLogxK
U2 - 10.1088/0029-5515/54/11/114017
DO - 10.1088/0029-5515/54/11/114017
M3 - Article
AN - SCOPUS:84908546280
VL - 54
JO - Nuclear Fusion
JF - Nuclear Fusion
SN - 0029-5515
IS - 11
M1 - 114017
ER -