Michael Stephen Poole1, Hector Sanchez Lopez1, Stuart Crozier1
1School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, QLD, Australia
Modelling gradient-induced eddy currents using eigenmode analysis reveals a set of non-interacting modes with characteristic exponential decays. These combine in conventional gradient coils to produce an eddy current that changes its magnitude and spatial form in time. This causes gradient pre-emphasis techniques to be ineffective over the whole imaging region. We propose, and demonstrate by simulation, that the eddy currents can be made more amenable to pre-emphasis by suppressing all but one mode. At the same time the primary field must match the field generated by this mode.