The magnetic shear scaling of particle and heat transport due to ion temperature gradient and trapped electron mode turbulence in quasilinear fluid descriptions is investigated in the collisionless limit. The study is focused on the influence of magnetic shear on the particle diffusivity and the related particle pinch comparing different fluid treatments of the trapped electron physics. The effective diffusivities are shown to be strongly reduced for negative and large positive magnetic shear. Furthermore, it is found that the sign of the particle flux reverses with magnetic shear as a result of the shear dependence of the curvature pinch. The effect of the shear dependence of transport for tokamak parameter values is illustrated with a comparative interpretative transport analysis for ITER-like profiles.
Global profile effects and structure formations in toroidal electron temperature gradient driven turbulence