Evidence of transport barrier in TCABR tokamak with high MHD activity

In this work we analyze the particle transport at the plasma edge during TCABR tokamak discharges with high MHD activity. The interpretation of this transport as chaotic, in a quasi integrable Hamiltonian system formed by the plasma flow and the drift waves, predicts its dependence on a confinement parameter, proportional to the difference between the plasma flow and the drift wave phase velocities. For the analyzed discharges, we observe a particle transport decrease where the confinement parameter has a maximum. In the considered quasi integrable description, this can be interpreted as an evidence of a localized transport barrier.