Fast electron flux driven by lower hybrid wave in the scrape-off layer

Journal Article · Sun Feb 15 00:00:00 EST 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4908542· OSTI ID:22408105

Li, Y. L.; Xu, G. S.; Wang, H. Q.; Wan, B. N.; Chen, R.; Wang, L.; Gan, K. F.; Yang, J. H.; Zhang, X. J.; Liu, S. C.; Li, M. H.; Ding, S.; Yan, N.; Zhang, W.; Hu, G. H.; Liu, Y. L.; Shao, L. M.; Li, J.; Chen, L.; Zhao, N. ^[1] ; others, and

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1. Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

The fast electron flux driven by Lower Hybrid Wave (LHW) in the scrape-off layer (SOL) in EAST is analyzed both theoretically and experimentally. The five bright belts flowing along the magnetic field lines in the SOL and hot spots at LHW guard limiters observed by charge coupled device and infrared cameras are attributed to the fast electron flux, which is directly measured by retarding field analyzers (RFA). The current carried by the fast electron flux, ranging from 400 to 6000 A/m{sup 2} and in the direction opposite to the plasma current, is scanned along the radial direction from the limiter surface to the position about 25 mm beyond the limiter. The measured fast electron flux is attributed to the high parallel wave refractive index n{sub ||} components of LHW. According to the antenna structure and the LHW power absorbed by plasma, a broad parallel electric field spectrum of incident wave from the antennas is estimated. The radial distribution of LHW-driven current density is analyzed in SOL based on Landau damping of the LHW. The analytical results support the RFA measurements, showing a certain level of consistency. In addition, the deposition profile of the LHW power density in SOL is also calculated utilizing this simple model. This study provides some fundamental insight into the heating and current drive effects induced by LHW in SOL, and should also help to interpret the observations and related numerical analyses of the behaviors of bright belts and hot spots induced by LHW.

• OSTI ID: 22408105
• Journal Information: Physics of Plasmas, Vol. 22, Issue 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANTENNAS
CAMERAS
CHARGE-COUPLED DEVICES
CURRENT DENSITY
DEPOSITION
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTRONS
HOT SPOTS
HT-7U TOKAMAK
LANDAU DAMPING
LOWER HYBRID HEATING
MAGNETIC FIELDS
NUMERICAL ANALYSIS
PLASMA SCRAPE-OFF LAYER
POWER DENSITY
REFRACTIVE INDEX
SPATIAL DISTRIBUTION