a plurality of magnet coils, each magnet coil comprising a former and a superconduting conductor would on said former and control windings of a non-superconducting material provided as over-bindings on the superconducting conductor of the magnet coil;

a supply connected to said magnet coils for operating the magnetic coils to generate, in combination, an operational magnetic field of a predetermined strength and homogeneity;

each control winding being formed of a material having a coefficient of thermal expansion of the magnet coil on which the control winding is ound, to restrain differential expansion between the magnet coil and the former thereof;

said control windings being configured and dimensioned to produce eddy currents that oppose magnetic field expansion caused by eddy currents in a remainder of a magnetic formed by said magnet coils, said eddy currents occurring upon quenching of said operational magnetic field; and

on at least some of said magnet coils, forming a subset of said plurality of magnetic coils, the respective control windings thereof being electically interconnected and the respective control windings of the magnet coils in said subset of magnet coils being interconnected with each other, and a control circuit that generates electrical current through the interconnected control windings of said subset of magnet coils in response to an onset of a quench, to automatically provide localized heating of the magnet coils in said subset of said magnet coils in response to said quench, to distribute the quench among said subset of magnet coils.