Results 41 to 50 of about 25,846,284 (157)

Zonal flow triggers the L-H transition in the Experimental Advanced Superconducting Tokamak [PDF]

, 2012
The kinetic energy transfer between shear flows and the ambient turbulence is investigated in the Experimental Advanced Superconducting Tokamak during the L-H transition.
C. Holland, H. Y. Guo, S. H. Müller, Cziegler, I, Holland, C, I. Cziegler, Müller, SH, Tynan, GR, M. Xu, K. Miki, P. H. Diamond, Manz, P, Xu, M, Xu, GS, Guo, HY, Wang, HQ, P. Manz, G. S. Xu, Fedorczak, N, Wan, BN, S. C. Thakur, N. Fedorczak, G. R. Tynan, Thakur, SC, Diamond, PH, B. N. Wan, H. Q. Wang, Miki, K   +27 more
core   +1 more source

Interplay between beam-driven chirping modes and plasma confinement transitions in spherical tokamak ST40

Nuclear Fusion, 2022
Experiments on the high field spherical tokamak ST40 have led to the recent observation of interplay between beam-driven modes of sweeping frequency (chirping modes) and transitions to the enhanced global confinement regime (H-mode) and back to the low ...
J. Bland, J. Varje, N.N. Gorelenkov, M.P. Gryaznevich, S.E. Sharapov, J. Wood, Team The ST40   +6 more
doaj   +1 more source

Shearless edge transport barriers in L-H transition [PDF]

, 2022
9 pages and 6 figuresThe L-H transition leads to a substantial reduction in transport levels in tokamaks and stellarators, improving the plasma confinement in such devices. After the transition, the plasma is in a high-confinement regime characterized by
Caldas, I. L., Osorio-Quiroga, L.A., M. Roberto, Roberto, M., R.L. Viana, Viana, R.L., I.L. Caldas, Osorio, L. A., L.A. Osorio-Quiroga, Caldas, I.L., Osorio-Quiroga, L. A., Y. Elskens, Elskens, Y., Viana, R. L.   +13 more
core   +1 more source

Impact of nitrogen seeding on L–H transitions and their role for detachment in ASDEX Upgrade

Nuclear Fusion
The required heating power, $P_{\mathrm{LH}}$ , to access the high confinement regime (H-mode) in nitrogen seeded deuterium plasmas is investigated at the ASDEX Upgrade tokamak. It is shown that a stepwise increase of the nitrogen seeding level increases
G. Birkenmeier, M. Bernert, D. Brida, P. David, R. Fischer, T. Happel, B. Kurzan, T. Lunt, F. Ryter, E. Wolfrum, the ASDEX Upgrade Team   +10 more
doaj   +1 more source

A new model of the L–H transition and H-mode power threshold

, 2018
In order to understand the mechanism of the confinement bifurcation and H-mode power threshold in magnetically confined plasma, a new dynamical model of the L–H transition based on edge instability phase transition (EIPT) has been developed.
Wu, Xingquan, Nielsen, Anders Henry, Ran, Chen, Chen, Liang, Xu, Guosheng, Rasmussen, Jens Juul, Linming, Shao, Naulin, Volker, Wan, Baonian, Ning, Yan   +9 more
core   +1 more source

Automated estimation of L/H transition times at JET by combining Bayesian statistics and support vector machines [PDF]

, 2009
This paper describes a pattern recognition method for off-line estimation of both L/H and H/L transition times in JET. The technique is based on a combined classifier to identify the confinement regime (L or H) at any time instant during a discharge. The
JET-EFDA Contributors, Vagliasindi, G., Vega, J., Rattá, G.A., Murari, A.   +4 more
core   +2 more sources

Influence of n = 1 resonant magnetic perturbation on flow and turbulence towards L-H transition

Nuclear Fusion
The application of resonant magnetic perturbation (RMP) with toroidal mode number n  = 1 on HL-3 tokamak inhibits the L-H transition at specific heating power.
Y. Zhang, M. Jiang, Z.B. Guo, P.H. Diamond, W.X. Guo, J.Q. Xu, N. Zhang, Z. Wang, Z.J. Li, Y. Zhou, A.S. Liang, T.F. Sun, R. Ke, S.B. Gong, X.X. He, W. Chen, W.L. Zhong   +16 more
doaj   +1 more source

Reduced model for H-mode sustainment in unfavorable drift configuration in ASDEX Upgrade

Nuclear Fusion
A recently developed reduced model of H-mode sustainment based on interchange-drift-Alfvén turbulence description in the vicinity of the separatrix matching experimental observations in ASDEX Upgrade has been extended to experiments with the unfavorable $
O. Grover, T. Eich, P. Manz, W. Zholobenko, T. Happel, T. Body, U. Plank, P. Ulbl, the ASDEX Upgrade Team   +8 more
doaj   +1 more source

Bifurcation analysis and dimension reduction of a predator-prey model for the L-H transition [PDF]

, 2013
The L-H transition denotes a shift to an improved confinement state of a toroidal plasma in a fusion reactor. A model of the L-H transition is required to simulate the time dependence of tokamak discharges that include the L-H transition.
Brøns, Morten, Juul Rasmussen, Jens, Dam, Magnus, Guosheng Xu, Xu, Guosheng, Volker Naulin, Morten Brøns, Naulin, Volker, Jens Juul Rasmussen, Magnus Dam   +9 more
core   +1 more source

Phase transition temperatures of 405-725 K in superfluid ultra-dense hydrogen clusters on metal surfaces

AIP Advances, 2016
Ultra-dense hydrogen H(0) with its typical H-H bond distance of 2.3 pm is superfluid at room temperature as expected for quantum fluids. It also shows a Meissner effect at room temperature, which indicates that a transition point to a non-superfluid ...
Leif Holmlid, Bernhard Kotzias
doaj   +1 more source