Edge cooling experiments and non-local transport phenomena in Tore Supra

Edge cooling experiments have been performed in Tore Supra by impurity inje ction and oblique pellet injection. Non-local transport (NLT) features have been confirmed in both cases in the ohmic regime. The pellet injection exp eriments have shown the existence of a threshold on the plasma density [n(e )] and current I-p for the observation of this effect: [n(e)]/I-p(1/2) less than or equal to 1.0 x 10(16) (m(-3) A(-1/2)). A second threshold on the r elative density variation caused by the pellet injection has also been obse rved: Delta [n(e)]/[n(e)] less than or equal to 0.5. It has been observed t hat in the L regime during lower hybrid current drive (LHCD) experiments th ese limits are extended: [[n(e)]/I-p(1/2)](crit) = 1.4 x 10(16) (m(-3) A(-1 /2)) and [Delta>(*) over bar * (n(e))/[n(e)]](crit) greater than or equal t o 0.65. Observations in a LHCD scheme with fully non-inductive plasma curre nt seem to indicate that the mechanism governing the NLT is unlikely to be linked to the plasma current profile effects including the spatial redistri bution, the magnetic shear, and the low-m MHD modes.