Optimization of the IGNITOR operating scenario at 11 MA

Several endeavours have been made, in the frame of the IGNITOR design, in order to minimize technological problems, reducing electromagnetic loads, power supply requirements while avoiding the use of not completely proven materials. The present design modifications comprise both the operating scenario for the poloidal field (PF) currents and the PF coils geometry. The new scenario and a relevant simulation of a related typical fast vertical disruption, in the most dangerous plasma conditions in IGNITOR, have been simulated with the MAXFEA code. er to reduce the EM loads on plasma chamber and the related stresses due to plasma disruptions, a new approach has been investigated based on the possibility of mitigating these loads by using copper toroidal layers added to the plasma chamber in proper positions. We found that this expedient could be quite effective not only in increasing the time constant of the plasma displacement but even in reducing the vertical force and its combined effect with hoop force on the vessel during a vertical displacement event (VDE).