A method for controlling a quench in a high temperature superconductor, HTS, magnet coil, the method comprising: coupling a current imbalance source to at least one coil subsection of an HTS magnet coil, wherein the HTS magnet coil comprises a plurality of coil subsections (120, 125; 220, 225), wherein the HTS magnet coil comprises an insulated conductor, and wherein the current imbalance source comprises an alternating current voltage source or a high impedance device, and wherein the current imbalance source further comprises a capacitive element coupled in series with the AC voltage source or the high impedance device, and wherein the AC voltage source or the high impedance device and the capacitive element are coupled across the at least one coil subsection of the HTS magnet coil; and operating the current imbalance source to induce a current imbalance in the at least one coil subsection of the HTS magnet coil to establish a high frequency change in a magnetic field of the HTS magnet coil resulting in inductive heating of the HTS magnet coil to control a quench in the HTS magnet coil; wherein the HTS magnet coil comprises a magnet power supply (107; 207) coupled across the plurality of coil subsections (120, 125; 220, 225), and wherein the HTS magnet coil comprises an insulated conductor, and wherein the current imbalance source comprises: an alternating current, AC, voltage source; and a capacitive element coupled in series with the AC voltage source, wherein the AC voltage source and the capacitive element are coupled across the at least one coil subsection of the HTS magnet coil; or wherein the current imbalance source comprises: an high impedance device; a capacitive element coupled in series with the high impedance device; and a switch coupled across the high impedance device and the capacitive element, wherein the high impedance device, the capacitive element and the switch are coupled across the at least one coil subsection of the HTS magnet coil, the high impedance device being placed on one of the leads of the HTS magnet power supply leading to the at least one coil subsection. coupling a current imbalance source to at least one coil subsection of an HTS magnet coil, wherein the HTS magnet coil comprises a plurality of coil subsections (120, 125; 220, 225), wherein the HTS magnet coil comprises an insulated conductor, and wherein the current imbalance source comprises an alternating current voltage source or a high impedance device, and wherein the current imbalance source further comprises a capacitive element coupled in series with the AC voltage source or the high impedance device, and wherein the AC voltage source or the high impedance device and the capacitive element are coupled across the at least one coil subsection of the HTS magnet coil; and operating the current imbalance source to induce a current imbalance in the at least one coil subsection of the HTS magnet coil to establish a high frequency change in a magnetic field of the HTS magnet coil resulting in inductive heating of the HTS magnet coil to control a quench in the HTS magnet coil; wherein the HTS magnet coil comprises a magnet power supply (107; 207) coupled across the plurality of coil subsections (120, 125; 220, 225), and wherein the HTS magnet coil comprises an insulated conductor, and wherein the current imbalance source comprises: an alternating current, AC, voltage source; and a capacitive element coupled in series with the AC voltage source, wherein the AC voltage source and the capacitive element are coupled across the at least one coil subsection of the HTS magnet coil; or wherein the current imbalance source comprises: an high impedance device; a capacitive element coupled in series with the high impedance device; and a switch coupled across the high impedance device and the capacitive element, wherein the high impedance device, the capacitive element and the switch are coupled across the at least one coil subsection of the HTS magnet coil, the high impedance device being placed on one of the leads of the HTS magnet power supply leading to the at least one coil subsection.