New edge coherent mode providing continuous transport in long-pulse H-mode plasmas

An electrostatic coherent mode near the electron diamagnetic frequency (20-90 kHz) is observed in the steep-gradient pedestal region of long pulse H-mode plasmas in the Experimental Advanced Superconducting Tokamak, using a newly developed dual gas-puff-imaging system and diamond-coated reciprocatin...

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Bibliographic Details
Published in:Physical review letters 2014-05, Vol.112 (18), p.185004-185004
Main Authors: Wang, H Q, Xu, G S, Wan, B N, Ding, S Y, Guo, H Y, Shao, L M, Liu, S C, Xu, X Q, Wang, E, Yan, N, Naulin, V, Nielsen, A H, Rasmussen, J Juul, Candy, J, Bravenec, R, Sun, Y W, Shi, T H, Liang, Y F, Chen, R, Zhang, W, Wang, L, Chen, L, Zhao, N, Li, Y L, Liu, Y L, Hu, G H, Gong, X Z
Format: Article
Language:English
Subjects:
Coherence
Coherence length
Diamagnetism
Diamonds
Dissipation
Plasmas
Reciprocating
Turbulent flow
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Summary:An electrostatic coherent mode near the electron diamagnetic frequency (20-90 kHz) is observed in the steep-gradient pedestal region of long pulse H-mode plasmas in the Experimental Advanced Superconducting Tokamak, using a newly developed dual gas-puff-imaging system and diamond-coated reciprocating probes. The mode propagates in the electron diamagnetic direction in the plasma frame with poloidal wavelength of ∼8  cm. The mode drives a significant outflow of particles and heat as measured directly with the probes, thus greatly facilitating long pulse H-mode sustainment. This mode shows the nature of dissipative trapped electron mode, as evidenced by gyrokinetic turbulence simulations.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.112.185004