Poloidal inhomogeneity of the particle fluctuation induced fluxes near of the LCFS at lower hybrid heating and improved confinement transition at the FT-2 tokamak

Sergei Lashkul (1) , Sergei Shatalin (1) , Alexei Altukhov (1) , Alexei Gurchenko (1) , Evgenii Gusakov (1) , Valerii Dyachenko (1) , Lev Esipov (1) , Mihail Kantor (1) , Denis Kouprienko (1) , Alexsandr Stepanov (1) , Andrei Sharpeonok (1) , Elena Vekshina (1)

1 HTPPL - High Temperature Plasma Physics Laboratory

This paper deals with the new spectral and microturbulence experimental data and their analysis, which show, that the radial electric field Er generated at the LH heating (LHH) in the FT-2 is high enough to form the transport barriers. The ETB is formed when LHH is switched off. The radial fluctuation-induced E≥B drift flux densities near LCFS in SOL are measured at two different poloidal angles. For this purpose two Langmuir probes located at low and high field sides of the torus are used. Registration of the poloidal and radial components of the electric field and density fluctuations at the same time during one discharge permits to measure the poloidal asymmetry of the transport reduction mechanism of the radial and poloidal particle fluxes in the SOL. The absolute E(~)Θ fluctuation levels show dependence on the sign of Er shear. The modification of the microscale turbulence by the poloidal Er x B rotation shear ΩE≥B at the L - H transition near LCFS is also studied by X-mode fluctuation Reflectometry. The new data were obtained by spatial spectroscopic technique.

Mots clés: Particle Fluctuation

Domaines: Physique des plasmas [physics.plasm-ph]

Sergei Lashkul, Sergei Shatalin, Alexei Altukhov, Alexei Gurchenko, Evgenii Gusakov, et al.. Poloidal inhomogeneity of the particle fluctuation induced fluxes near of the LCFS at lower hybrid heating and improved confinement transition at the FT-2 tokamak. 2004. ⟨hal-00001766v2⟩