2-D mapping of ICRF-induced SOL perturbations in Tore Supra tokamak
ICRF-induced SOL modifications are mapped for the first time in 2-D around Tore Supra ICRF antennas using reciprocating Langmuir probes. When probe heads are magnetically connected to powered antennas, radical modifications of floating potentials V(float), effective temperatures T(eff) and ion saturation currents are observed. V(float) perturbations are located radially near antenna limiters, with a typical extension 2 cm. Poloidally they are locally minimal near the equatorial plane, and maximal near antenna box corners. Two possible interpretations for increased T(eff) are proposed: localised electron heating and RF loop voltage induced along probe circuit. Both interpretations rely on the generation of parallel RF fields by parallel RF currents on the antenna structure. The topology of such currents could explain the 2-D structure of T(eff) maps. Both interpretations also imply a positive DC biasing of the antenna environment. Differential biasing of nearby flux tubes drives DC E x B(0) convection that could explain 2-D density patterns.
Bibliographic Reference: An article published in: Journal of Nuclear Materials (2007), online edition
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://www.sciencedirect.com/science/journal/00223115
Record Number: 200718974 / Last updated on: 2007-03-26
Original language: en
Available languages: en