Results 251 to 260 of about 4,141,636 (301)

Tokamak L/H mode transition

Physics of Plasmas, 2012
Through the non field-aligned rotational tokamak equilibrium of a divergence-free plasma flow with a pair of transformed plasma variables w→*=(μρ)1/2ν→ and μp*=(μp+w*2/2) [K. H. Tsui, Phys. Plasmas 18, 072502 (2011)], a preliminary understanding of the L/H equilibrium transition is proposed through a feedback cycle, where the higher plasma flux due to ...
K. H. Tsui, C. E. Navia
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Dynamics of the L - H transition

Plasma Physics and Controlled Fusion, 1996
Dynamics of the L - H and H - L transitions are addressed numerically. The focus is on the power level slightly above the threshold. Therefore, at the edge the electric field is assumed to be neoclassical and the toroidal rotation to be damped by anomalous viscosity and inertia. The diffusion coefficient depends on the shear of the electric field.
V Rozhansky, M Tendler, S Voskoboinikov
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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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Probabilistic Nature in L/H Transition

Journal of the Physical Society of Japan, 1999
Statistical picture for an excitation of a plasma transition is examined, which occurs in a strongly turbulent state. The physical picture of transition phenomena is extended to include the statistical variances. The dynamics of the plasma density and turbulent-driven flux is studied with hysteresis nature in the flux-density relation.
Shinichiro Toda, Sanae-I. Itoh, Masatoshi Yagi, Kimitaka Itoh, Atsushi Fukuyama   +4 more
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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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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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L–H transition in tokamak plasmas: 1.5-D simulations

Journal of Nuclear Materials, 1999
Abstract Time-dependent theoretical models have been implemented in a 1.5-D transport code to describe the operational boundaries (L–H transition, ballooning limit) in terms of edge parameters. The width of the H-mode transport barrier (F. Wagner et al., Phys. Rev. Lett.
Janeschitz, G., Pacher, G., Igitkhanov, Y., Pacher, H., Pinches, S., Pogutse, O., Sugihara, M.   +6 more
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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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Understanding L–H transition in tokamak fusion plasmas

Plasma Science and Technology, 2017
This paper reviews the current state of understanding of the L–H transition phenomenon in tokamak plasmas with a focus on two central issues: (a) the mechanism for turbulence quick suppression at the L–H transition; (b) the mechanism for subsequent generation of sheared flow.
Guosheng XU, Xingquan WU
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