STOCHASTIC DIFFUSION IN THE PRESENCE OF MODE-LOCKING IN A REVERSED-FIELD PINCH

In this paper the problem of stochastic diffusion in a reversed field pinch (RFP) plasma in the presence of mode-locking has been addressed. In order to understand its effects, different spectral shapes of the perturbing magnetic field have been compared. The importance of long-w avelength perturbations in determining the stochastic diffusion proces s is pointed out. Moreover, we have considered the effect on energy tr ansport and the conclusion has been reached that, due to the high para llel thermal conduction, 'local' effects are not important. A comparis on of the experimental values of the energy confinement time with that deduced assuming a collisionless stochastic transport model is also g iven.