Abstract: Novel apparatus and methods for magnetic resonance imaging are disclosed which improve imaging speed and resolution as well as increase efficiency, particularly in superconducting systems. In one aspect of the invention, it has been discovered that the eddy currents and harmonics which normally interfere with MRI operations can be suppressed by the construction of an active shield about the gradient-forming components of the system. The active shield, for example, can be implemented by another set of coils, placed between the gradient coils and the cryostat in a superconducting MRI system to zero particular harmonics and prevent eddy currents in the cryostat shells. By employing a set of active secondary coils the problems associated with eddy currents induced by the gradient producing coils are substantially controlled.

Abstract: This invention relates to means for the structural support of the windings of saddle and racetrack-shaped magnets against the local magnetic loads acting on the individual conductors or against the total transverse magnetic loads acting on the entire windings. The invention is particularly useful in magnets used in magnetohydrodynamic [MHD] applications. The invention utilizes the inherent stiffness of the windings themselves and any internal or substructure present within the windings. The invention comprises a pair of first and second winding assemblies, an assembly of each pair being positioned on each side of the MHD channel. Each winding assembly consists either of an integral winding pancake or one or more substructural plates, each of which has a channel or channels running its length and into which an individual conductor or several conductors of the magnet are placed. Winding pancakes or plates are assembled with a means to provide shear transmission from pancake to pancake or from plate to plate.