Shear, temperature gradient and collisionality dependences of particle pinches in JET

The peakedness of density profiles in L-modes and in H-modes exhibits remarkably different behaviour. The former scales with overall plasma shear in accordance with turbulent equi-partition (TEP) theory (ne0/ ∼ 1.5 li), independently of collisionality. On the other hand, peaking in H-modes depends on collisionality, with ne0/ increasing from ∼ 1.2 at νeff) = 1 to ne0/ ∼ 1.6 at the collisionality of the ITER reference H-mode, νeff ∼ 0.1. H-mode density profiles show no shear dependence, except for νeff ≤ 0.2. Evidence for LTe, LTi or ρ* dependences has been obtained neither in L nor in H-modes. Carbon density profiles from CXS are always less peaked than electron density profiles. (authors)