A superconducting device includes a first superconducting wire configured to carry a first current in a superconducting state, and to generate thermal energy upon occurrence of a hot spot during conduction. The device includes a second superconducting wire, thermally coupled to and electrically isolated from the first superconducting wire. The second superconducting wire is configured to conduct a second current in a superconducting state below, but sufficiently near its critical surface to be quenched to a non-superconducting state upon conduction of the thermal energy from the first superconducting wire.

According to one embodiment, a MRI apparatus determines a first time during which a subsidiary power supply is capable of supplying power to a cooling device based on a capacity of the subsidiary power supply when power outage of a main power supply occurs, and determines a second time needed to demagnetize a superconducting magnet based on an excitation current of the superconducting magnet and a temperature of the superconducting magnet. The MRI apparatus determines starts ramp-down of the superconducting magnet after a third time based on the first time and the second time has elapsed from initiation of power outage of the main power supply.

According to one embodiment, a MRI apparatus determines a first time during which a subsidiary power supply is capable of supplying power to a cooling device based on a capacity of the subsidiary power supply when power outage of a main power supply occurs, and determines a second time needed to demagnetize a superconducting magnet based on an excitation current of the superconducting magnet and a temperature of the superconducting magnet. The MRI apparatus determines starts ramp-down of the superconducting magnet after a third time based on the first time and the second time has elapsed from initiation of power outage of the main power supply.

Techniques are described for lowering strains applied to superconducting material in a superconducting magnet by arranging structural partitions between turns of the superconducting material that intercept and transfer strain to a mechanically stronger structure, such as the housing of the magnet. A structural partition may be formed with a feedthrough slit so that the superconducting aterial can easily pass through the partition. A number of structural partitions may be interspersed between groups of turns of super-conducting material in a magnet so that forces can be sufficiently distributed by the partitions throughout the magnet. At the same time, the number of structural partitions may be selected to minimize the amount of space within the magnet occupied by the partitions that could otherwise be occupied by current-carrying superconducting material.

Techniques are described for lowering strains applied to superconducting material in a superconducting magnet by arranging structural partitions between turns of the superconducting material that intercept and transfer strain to a mechanically stronger structure, such as the housing of the magnet. A structural partition may be formed with a feedthrough slit so that the superconducting aterial can easily pass through the partition. A number of structural partitions may be interspersed between groups of turns of super-conducting material in a magnet so that forces can be sufficiently distributed by the partitions throughout the magnet. At the same time, the number of structural partitions may be selected to minimize the amount of space within the magnet occupied by the partitions that could otherwise be occupied by current-carrying superconducting material.

A device comprising a high temperature superconductor, HTS, circuit; wherein the HTS circuit comprises: a quenchable section comprising HTS material and connected in series to other elements of the HTS circuit, the HTS material comprising a stack of HTS takes comprising at least one HTS tape; the device further comprising: a quenching system configured to quench the HTS material in the quenchable section; a quench protection system configured to detect temperature rises in the HTS circuit and, in response to detection of a temperature rise, cause the quenching system to quench the superconducting material in the quenchable section in order to dump stored magnetic energy from the HTS circuit into the quenchable section; wherein the HTS circuit is configured such that, when in use, the magnetic field on the or each HTS tape is substantially parallel to a a-b plane of the HTS tape, and the quenching system is configured to quench the HTS material by producing an additional magnetic field along the length of the or each HTS tape within the quenchable section, such that the additional magnetic field has a component perpendicular to the a-b plane of the HTS tape.

A device comprising a high temperature superconductor, HTS, circuit; wherein the HTS circuit comprises: a quenchable section comprising HTS material and connected in series to other elements of the HTS circuit, the HTS material comprising a stack of HTS takes comprising at least one HTS tape; the device further comprising: a quenching system configured to quench the HTS material in the quenchable section; a quench protection system configured to detect temperature rises in the HTS circuit and, in response to detection of a temperature rise, cause the quenching system to quench the superconducting material in the quenchable section in order to dump stored magnetic energy from the HTS circuit into the quenchable section; wherein the HTS circuit is configured such that, when in use, the magnetic field on the or each HTS tape is substantially parallel to a a-b plane of the HTS tape, and the quenching system is configured to quench the HTS material by producing an additional magnetic field along the length of the or each HTS tape within the quenchable section, such that the additional magnetic field has a component perpendicular to the a-b plane of the HTS tape.

A current lead for supplying current to a superconducting device, the current lead having a high temperature superconductor (HTS) conductor extending along a length of the current lead, the HTS conductor thermally and electrically joined to an electrical shunt. Voltage taps are connected to respective ends of the HTS conductor for connection to a quench heater in thermal contact with a superconducting device. A quench in the HTS conductor gives rise to a voltage appearing between the voltage taps, and the voltage is applied to the quench heater to give rise to quench within the superconducting device.

A current lead for supplying current to a superconducting device, the current lead having a high temperature superconductor (HTS) conductor extending along a length of the current lead, the HTS conductor thermally and electrically joined to an electrical shunt. Voltage taps are connected to respective ends of the HTS conductor for connection to a quench heater in thermal contact with a superconducting device. A quench in the HTS conductor gives rise to a voltage appearing between the voltage taps, and the voltage is applied to the quench heater to give rise to quench within the superconducting device.

According to some aspects, techniques are described for designing non-insulated (NI) high temperature superconductor (HTS) magnets that mitigate problems that may arise during quench initiation and propagation. Coupling the HTS material to a co-conductor along its length reduces the effective resistance of the conductive path along the HTS material when it is not superconducting, and that this leads to numerous advantages for quench mitigation.