Results 231 to 240 of about 694,012 (248)

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
openaire   +2 more sources

Critical assessment of ion loss mechanisms for L-H transition

Plasma Physics and Controlled Fusion, 2000
Monte Carlo ion simulation of the tokamak edge, based on the neoclassical radial current balance, shows that a considerable E×B shear, relevant for turbulence suppression, can be generated by orbit losses. In contrast to earlier orbit loss models, no spontaneous bifurcation of the radial electric field Er is found. However, a bifurcation and a solitary
Kiviniemi, T., Heikkinen, J., Peeters, A., Kurki-Suonio, T., Sipilä, S.   +4 more
openaire   +3 more sources

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
openaire   +1 more source

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.
openaire   +2 more sources

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
openaire   +2 more sources

Electron density evolution after L–H transitions and the L–H/H–L cycle in ASDEX Upgrade

Nuclear Fusion, 2012
Abstract The development of the electron density profile and its dependences after the L–H transition have been investigated. Only electron cyclotron resonance heated H-modes have been analysed to exclude core particle fuelling. While the density gradient in the edge transport barrier increases significantly after the L–H transition, the
Willensdorfer, M., Wolfrum, E., Scarabosio, A., Aumayr, F., Fischer, R., Kurzan, B., McDermott, R., Mlynek, A., Nold, B., Rathgeber, S., Rohde, V., Ryter, F., Sauter, P., Viezzer, E.   +13 more
openaire   +2 more sources

Transport modelling of L - H transition and barrier formation

Plasma Physics and Controlled Fusion, 1996
The mechanism of L - H transition and transport barrier formation is studied by the use of a one-dimensional transport code including plasma rotation and radial electric field. Particle transport simulation with a fixed temperature profile has indicated that the density profile is quite sensitive to the edge plasma temperature.
A Fukuyama, Y Fuji, S-I Itoh, M Yagi, K Itoh   +4 more
openaire   +1 more source

L-H transition studies at JET

One of the most beautiful phenomena we observe in tokamaks is the transition between L and H-mode, a clear phase transition. Here we present and discuss results from dedicated L-H transition experiments at JET-ILW [ER Solano et al, Nuclear Fusion 63 (11), 112011, 2023]. Uniquely, we studied the power threshold in plasmas composed of pure Tritium, to be
openaire   +1 more source

Warm-ion drift Alfvén turbulence and the L-H transition

Plasma Physics and Controlled Fusion, 1998
Computations of fluid drift turbulence treating ions and electrons on equal footing, including both temperatures, are conducted in a model toroidal geometry. The resulting `ion mixing mode' turbulence bears features of both electron drift-Alfven and ion temperature gradient turbulence, and nonlinear sensitivity to the relative strengths of the density ...
openaire   +2 more sources

L-H transition studies in JET-ILW

2017
Recent experiments at JET have produced new results about the L-H transition. We will present a selection here. We found the power threshold depends on H/(H+D) species concentration in a non-linear manner, with much of the variation taking place at the extremes of the mixture scan.
Solano ER, Delabie E, Hillesheim, Maggi C, Vianello N, Carvalho I, Huber A, Lerche E   +7 more
openaire   +1 more source