Poloidal asymmetry and dynamics of perpendicular flow in Tore Supra plasmas

摘要

The mechanism at the origin of the poloidal asymmetry observed in the perpendicular flow measured in the Tore Supra plasmas is investigated. For a wide range of plasma conditions, the perpendicular velocity, measured using Doppler backscattering technique in the core of limited Lmode plasmas is larger in the equatorial plane at the low field side (θ~ 0°) than in the vertical one at the top of the plasma (θ~ 90°). Among the possible explanations of such poloidal asymmetry, the generation of convective cells by the ballooned structure of the underlying turbulence has been proposed. In this present paper, experimental evidence of such convective cells is investigated through the dynamics of the measured perpendicular velocity.