Bifurcation phenomena and transport in magnetized plasmas

The character of the transition between the thermal equilibria characterized by different level of anomalous transport is investigated for the laboratory plasm as confined by toroidal magnetic field. The anomalous transport in such plasmas is driven by the instability of drift type, namely by the ion temperature gradient driven turbulence. It is found that both first-order and second-order phase transition is possible in this system dependent on the magnetic field topology. The application of these results for understanding the physical mechanisms of the formation of transport barrier (i.e. steep gradient) on the temperature profile observed in experimental discharges is discussed. (C) 2003 Published by Elsevier B.V.