Results 221 to 230 of about 723,509 (268)

Fast responses in L-H transitions

Nuclear Fusion, 1999
An equation which includes a non-local effect in the heat flux is introduced to study transient transport phenomena. A non-local heat flux, which is expressed in terms of an integral equation, is superimposed on the conventional form of the heat flux. This model is applied to describe the fast responses in the transition from L mode to H mode.
T Iwasaki, S Toda, S.I Itoh, M Yagi, K Itoh   +4 more
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A review of theories of the L-H transition

Plasma Physics and Controlled Fusion, 1999
After a general discussion of the experimental characteristics of the L-H transition and consideration of basic theoretical principles underlying models for it, this paper reviews the various theories of the L-H transition available in the literature, providing some background information on each theory and expressing the transition criteria in forms ...
J W Connor, H R Wilson
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Edge ion parameters at the L–H transition on JET

Plasma Physics and Controlled Fusion, 2003
L–H transition experiments have recently been performed on JET to characterize the local edge ion parameters. Evidence of a threshold in the edge ion temperature to access the H-mode is presented and comparisons are made with edge electron temperature. These results provide the first scaling of pedestal ion temperature on JET.
Andrew, Y., Hawkes, N., O'Mullane, M., Sartori, R., Beurskens, M., Coffey, I., Joffrin, E., Loarte, A., McDonald, D., Prentice, R., Saibene, G., Suttrop, W., Zastrow, K., ASDEX Upgrade Team   +13 more
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L-H transition in the mega-amp spherical tokamak.

Physical review letters, 2002
H-mode plasmas have been achieved on the MAST spherical tokamak at input power considerably higher than predicted by conventional threshold scalings. Following L- H transition, a clear improvement in energy confinement is obtained, exceeding recent international scalings even at densities approaching the Greenwald density limit.
Akers, R.J., Counsell, G.F., Sykes, A., Appel, L.C., Arends, E.R., Byrom, C., Carolan, P.G., Conway, N.J., Cunningham, G., Dnestrovskij, A., Dnestrovskij, Y.N., Field, A.R., Fielding, S.J., Gryaznevich, M., Helander, P., Kirk, A., Korsholm, S., Martin, R., Meyer, H., Nightingale, M.P. S., Roach, C.M., Shevchenko, V., Torunianski, M., Walsh, M.J., Warrick, C.D.   +24 more
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Physics of GAM-initiated L–H transition in a tokamak

Plasma Physics and Controlled Fusion, 2016
Based on experimental observations using the TUMAN-3M and FT-2 tokamaks, and the results of gyrokinetic modeling of the interplay between turbulence and the geodesic acoustic mode (GAM) in these installations, a simple model is proposed for the analysis of the conditions required for L–H transition triggering by a burst of radial electric field ...
L G Askinazi, A A Belokurov, V V Bulanin, A D Gurchenko, E Z Gusakov, T P Kiviniemi, S V Lebedev, V A Kornev, T Korpilo, S V Krikunov, S Leerink, M Machielsen, P Niskala, A V Petrov, A S Tukachinsky, A Yu Yashin, N A Zhubr   +16 more
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Neoclassical transport and poloidal rotation at the L-H transition

Physica Scripta, 1995
We address the question of establishing if, and under what physical and boundary conditions, the neoclassical transport is quantitatively capable of establishing high gradients in a narrow layer at the edge of an auxiliary heated tokamak plasma, and of driving poloidal rotation in the absence of external momentum input and vanishing parallel viscous ...
G Gervasini, E Lazzaro, E Minardi
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L‐H Transition Experiments in TJ‐II

Contributions to Plasma Physics, 2010
AbstractIn the TJ‐II stellarator, L‐ to H‐mode transitions are achieved under NBI heating conditions when operating with lithium coated walls. Several magnetic configurations have been explored in order to study the influence of the rotational transform in the transition.
T. Estrada, E. Ascasíbar, T. Happel, C. Hidalgo, E. Blanco, R. Jiménez‐Gómez, M. Liniers, D. López‐Bruna, F.L. Tabarés, D. Tafalla   +9 more
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Theory of the L-H transition

1994
The theory of the L-H transition in tokamaks is discussed. A transport bifurcation model is presented, which predicts reasonably well several properties of the L-H transition in the DIII-D tokamak, including the evolution in time of the density and temperature profiles.
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Transport Modeling of L/H Transition in Tokamaks

Fusion Technology, 1995
In order to study the particle transport and the mechanism of the L/H transition in tokamaks, a one-dimensional transport code which describes the toroidal and poloidal plasma rotation as well as the radial electric field has been developed. The neoclassical transport, turbulent transport and ion orbit loss are included.
Y. Fuji, K. Itoh, A. Fukuyama, S.-I. Itoh   +3 more
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Statistical theory of L H transition in tokamaks*

Plasma Physics and Controlled Fusion, 2003
A statistical model for the bifurcation of the radial electric field Er is developed in view of describing L–H transitions of tokamak plasmas. Noise in micro-fluctuations is shown to lead to random changes of Er, if a deterministic approach allows for more than one solution.
S-I Itoh, K Itoh, S Toda
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