Investigation of the Ion Energy Transport in the Scrape-Off Layer on the J-TEXT Tokamak Using a Retarding Field Analyzer

摘要

Radial profiles of the ion temperature,T_i,have been measured by a double-sided retarding field analyzer(RFA) in the scrape-off layer(SOL) of the J-TEXT tokamak(R = 105 cm,r = 25-29 cm,B_t = 1.8-2.0 T,I_p = 120-180 kA,n_e =(2-2.5) × 10^(19) m^(-3)).Strongly declining T_i profiles in the SOL have been found.The different e-folding lengths,At,of the T_i profiles in two experimental configurations with different magnetic connection lengths,L_c,reveal that a longer L_c results in weaker parallel energy transport and longer At.In similarity with the particle transport across the SOL,At is approximately proportional to the square root of L_c.Additionally,the poloidal asymmetry has been identified with enhanced ion energy transport across the SOL on the low-field side.