[en] The radial particle transport is considered in a plasma with ergodic and stochastic flux lines. The self consistent electric field is neglected and the particle flux is due to a succession of mass convections along flux lines in series with transverse diffusions at very small scale between neighbouring flux lines. We investigate the dependence of the average radial flux in terms of the thermodynamic forces, namely the pressure gradient which controls the parallel convection and the density gradient which controls the small scale transverse diffusion. The condition for which the average radial flux is driven by the average pressure or density gradient is derived