ECRH AS A TOOL FOR DISRUPTION CONTROL ON FTU

The use of ECRH as a possible technique to mitigate or avoid disruptions on the Frascati Tokamak Upgrade (FTU) has been further developed after the preliminary promising results reported in the last EC-14 [G. Granucci, et al., Proc. of 14th Joint Workshop on ECE and ECRH, Santorini, Greece (2006)]. The crucial role of MHD in the final phase of a disruption and the effectiveness of the EC power in stabilizing the growing modes, thus saving the discharge, has been shown. In the FTU experiments the reduction of one island width, by means of direct EC heating automatically triggered by the V_loop increase at the beginning of the disruption current quench, leads to the reduction of the other(s) coupled mode(s). The strong mode coupling, observed in the phase approaching the disruption, can be used to resolve the problem of the radial tracking of the mode to be suppressed, opening the road to a powerful strategy for ITER.