Calculation of AC loss in coated conductor coils with a large number of turns

For superconducting coils with many turns, it is widely believed that the magnetic field from magnetization currents is negligible compared with the one generated by the whole coil. This paper shows that this is not the case, from a few turns up to a considerable number of turns (thousands). We introduce a method to accurately calculate the AC loss in coils with virtually any number of turns that takes the magnetization currents into account. The current density and AC loss are analyzed for two windings made of a coated conductor consisting of a stack of 32 pancake coils totaling 768 and 6400 turns, respectively.