Modelling of plasma start-up in ITER

A general eigenexpansion/least squares fit algorithm is described which can be used to determine the PF coil voltage waveforms required to break down, initiate, and ramp a plasma current in a tokamak. The technique is applied to ITER (International Thermonuclear Experimental Reactor). The technique includes the effects of passive structure eddy currents. In addition, the eigenexpansion technique does not require a time step size consistent with any numerical stability limits. The constant voltages during each time segment calculated on the basis of the procedure described produce the desired loop voltage and field quality during the three phases of start-up