Investigation of the Ion Energy Transport in the Scrape Off Layer on the J TEXT Tokamak Using a Retarding Field Analyzer
Radial profiles of the ion temperature, Ti, 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, Bt 1.8 2.0 T, Ip 120 180 kA, ne (2 2.5) x 1019 m 3) Strongly declining Ti profiles in the SOL have been found. The different e folding lengths, lT, of the Ti profiles in two experimental configurations with different magnetic connection lengths, Lc, reveal that a longer Lc results in weaker parallel energy transport and longer lT. In similarity with the particle transport across the SOL, lT is approximately proportional to the square root of Lc. Additionally, the poloidal asymmetry has been identified with enhanced ion energy transport across the SOL on the low field side.