Current Rise Studies at ASDEX Upgrade and JET in Preparation for ITER
ITER requires routine operation at 15MA, with a robust current rise phase. The working margins are small (reduced operational space) compared to today's experiments. One example is the necessity to stay within li ~0.7-1.0 at 15MA; the minimum li ~0.7 set by the ability of the poloidal field coils to keep a divertor configuration, the maximum li ~1.0 is given by limitations of the transformer to provide enough flat top pulse length (400s). Simulations of the ITER current rise phase need to be validated by a coordinated set of experiments. Data from dedicated experiments in AUG and JET are used to document the requirements for the current rise and breakdown phase in ITER. The results obtained provide input to scenario simulation codes, used to predict the current rise phase for ITER. The focus here is on breakdown phase and control of li during the current rise phase, not only to stay within the planned ITER hardware limitations, but to provide a range of target q-profiles for the burn phase, and target plasmas for advanced scenarios.