Influence of Li conditioning on Lower Hybrid Current Drive efficiency in H-mode and L- mode plasmas on EAST
a CEA, IRFM, F-13108 Saint Paul-lez-Durance, France
b Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
* Corresponding author: firstname.lastname@example.org
Published online: 23 October 2017
The lower hybrid current drive efficiency on the EAST tokamak is estimated on a large database of low loop voltage discharges (VL<120mV) covering the 2016 campaign starting with lithium-free plasma facing components and ending with strong cumulated deposition of lithium. The efficiency is found to vary in a wide range from 0.6 to 1.2×1019A.W-1.m-2. No deleterious effect of the density on the efficiency is found between 2.3 and 3.2×1019m-3. The high efficiency occurs after strong lithium evaporation. The low effective charge Zeff and the higher temperature <Te> of these discharges, can account for the high efficiency according to the expected scaling with Zeff and <Te>. Modelling with a ray-tracing code coupled to a Fokker-Planck solver supports this result, assuming that the fast electron transport is reduced in the zero loop voltage discharge with high efficiency.
© The authors, published by EDP Sciences, 2017
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