Velocity fluctuations and transport in the JET boundary region

A new approach for turbulent fluxes and omega (EXB) measurements in the bul k plasma is proposed. It is based in the measurement of fluctuations in the phase velocity of fluctuations. The structure of turbulence has been inves tigated in the JET plasma boundary region with a fast reciprocating Langmui r probe system. Fluctuations in the radial and poloidal phase velocity have been computed from floating potential and ion saturation current measureme nts. The correlation between density fluctuations and fluctuations in the r adial velocity of fluctuations signals show a good agreement with the turbu lent transport computed from the correlation between density and poloidal e lectric field fluctuations. These results suggest that turbulent transport might be computed in the plasma core from measurement of density fluctuatio ns. ExB sheared flows, both constant and varying in time, are close to the critical value to trigger the transition to improve confinement regimes bel ow the power threshold to trigger the formation of transport barriers.