EP4659267A1

EP4659267A1 - Current pulse quench heating schemes for no-insulation superconducting magnets

Info

Publication number: EP4659267A1
Application number: EP24709600.1A
Authority: EP
Inventors: Brian LABOMBARD; Robert MUMGAARD
Original assignee: Massachusetts Institute of Technology; Commonwealth Fusion Systems LLC
Current assignee: Massachusetts Institute of Technology; Commonwealth Fusion Systems LLC
Priority date: 2023-01-31
Filing date: 2024-01-30
Publication date: 2025-12-10
Also published as: KR20250140510A; WO2024163432A1; JP2026505067A

Abstract

Systems and methods are provided herein for inducing quench in a non-insulated superconducting magnet. Some techniques described herein provide for operating the non-insulated superconducting magnet by applying a first current to the non-insulated superconducting magnet, and inducing quench in the non-insulated superconducting magnet at least in part by applying a second current to the non-insulated superconducting magnet, wherein the second current is opposite in direction to the first current.

Description

CURRENT PULSE QUENCH HEATING SCHEMES FOR NO-INSULATION SUPERCONDUCTING MAGNETS

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 62/482,382, filed January 31, 2023, which is hereby incorporated by reference in its entirety.

FIELD

This application relates to non-insulated superconducting magnets and, more particularly, to systems and methods for inducing quench in non-insulated superconducting magnets.

BACKGROUND

Superconductors are materials that have no electrical resistance to current (are “superconducting”) below some critical temperature. For many superconductors, operation of these materials in a superconducting state below the critical temperature requires significant cooling, such as with liquid helium or supercritical helium.

High-temperature superconducting (HTS) magnets can experience quench. Quench is the transition of the superconductor of a magnet from a superconducting state to a non- superconducting state.

SUMMARY

Some embodiments are directed to a method for inducing quench in a noninsulated superconducting magnet, the method comprising: operating the non-insulated superconducting magnet by applying a first current to the non-insulated superconducting magnet; and inducing quench in the non-insulated superconducting magnet at least in part by applying a second current to the non-insulated superconducting magnet, wherein the second current is opposite in direction to the first current.

Some embodiments are directed to a system for inducing quench in a non-insulated superconducting magnet, the system comprising: the non-insulated superconducting magnet; and a controller configured to: operate the magnet by applying a first cunent to the non-insulated superconducting magnet; and induce quench in the magnet at least in part by applying a second current to the magnet, wherein the second current is opposite in direction to the first current.

Some embodiments are directed to a superconducting non-insulated magnet, comprising: a plate; a plurality of turns of superconducting material within a groove of the plate, the plurality of turns extending from a first terminal at which a first electrical connection extends to an exterior of the plate and a second terminal at which a second electrical connection extends to the exterior of the plate; a first extension including a first partial turn of the superconducting material extending past the first terminal; and a second extension including a second partial turn of the superconducting material extending past the second terminal.

Some embodiments are directed to a system comprising a superconducting noninsulated magnet as described herein and a controller configured to operate the superconducting non-insulated magnet by applying a first current to the superconducting non-insulated magnet.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects and embodiments will be described with reference to the following figures. It should be appreciated that the figures are not necessarily draw n to scale. For purposes of clarity', not every component may be labeled in every drawing. In the drawings:

FIG. 1 illustrates example components of a magnet on which quench heating techniques may be implemented, in accordance with some embodiments described herein.

FIG. 2 A illustrates a top-side of an in-wind plate of the example magnet of FIG. 1, in accordance with some embodiments of the technology described herein.

FIG. 2B illustrates an underside of the example in-wind plate of FIG. 2A, in accordance with some embodiments of the technology described herein.

FIG. 2C illustrates a top-side of an out-wind plate of the example magnet of FIG. 1, in accordance with some embodiments.

FIG. 2D illustrates an underside of the example out-wind plate of FIG. 2C, in accordance with some embodiments of the technology described herein.

FIG. 2E illustrates an example of a terminal plate of the example magnet of FIG. 1, in accordance with some embodiments of the technology described herein. FIG. 2F illustrates an underside of the example terminal plate of FIG. 2E, in accordance with some embodiments of the technology described herein.

FIG. 2G illustrates a cross sectional view of a stack of structures of a magnet, in accordance with some embodiments of the technology described herein.

FIG. 3 illustrates an example of a pair of plates of the example magnet of FIG. 1, in accordance with some embodiments of the technology described herein.

FIG. 4 illustrates an example method for inducing quench in a non-insulated magnet, in accordance with some embodiments of the technology described herein.

FIG. 5 illustrates an example plot illustrating current applied to the magnet over time during the example method of FIG. 4, in accordance with some embodiments of the technology described herein.

FIG. 6 illustrates an example plot illustrating temperature generated by the magnet over time during the example method of FIG. 4, in accordance with some embodiments of the technology' described herein.

FIG. 7 is an example diagram illustrating the path of current in anon-insulated magnet during application of a first current to the magnet, in accordance with some embodiments of the technology described herein.

FIG. 8 is an example diagram illustrating the path of current in anon-insulated magnet during a period where the magnet is open circuited, in accordance with some embodiments of the technology described herein.

FIG. 9 is an example diagram illustrating the path of the component of current that is driven in a non-insulated magnet due to application of a rapid pulsed current applied to the terminals, in accordance with some embodiments of the technology described herein.

FIGS. 10A-H illustrate alternative conductor and joint arrangements to facilitate a quench heating function, in accordance with some embodiments of the technology' described herein.

FIGS. 11 A-H illustrate alternative arrangements for partial quench heating functions, in accordance with some embodiments of the technology described herein.

FIGS. 12A-C illustrate examples of control circuitry including a no-insulation magnet, in accordance with some embodiments of the technology described herein. DETAILED DESCRIPTION

Electromagnets ( "magnets") may have conductors disposed around an axis for a plurality of turns. Conventional magnets have an insulated conductor, with electrically insulating material disposed around the conductor that prevents a current path from forming to the outside of the conductor. An electromagnet formed of superconductor has zero resistance through the conductor when it is in the superconducting state.

Non-insulated (NI) magnets are superconducting electromagnets having at least partially electrically conductive paths between adjacent turns of superconductor. When the conductor is in the superconducting state there is zero resistance and voltage difference between turns during steady state operation, and all the current flows through the superconductor. The term '"NI" as used herein is intended to cover both magnets traditionally referred to as NI magnets and magnets traditionally referred to as partially insulated (PI) magnets, as the techniques and structures described herein apply to both types of magnets.

Certain NI magnets may be exceptionally strong mechanically and exhibit excellent stability against formation of non-superconducting zones that lead to quench. Quench is the transition of the superconductor of a magnet from a superconducting state to a non-superconducting state. A robust NI magnet may include one or more plates made of steel or another metal, with superconductor positioned in grooves of the plate(s). In some circumstances, however, even the more robust magnets may be become thermally unstable, resulting in quench. A region of superconducting material transitions from a superconducting state to a non-superconducting state when the conditions for maintaining superconductivity cease to be met, which occurs, for example, when the temperature exceeds the critical temperature. The critical temperature may depend upon various parameters. For a high temperature superconductor (HTS), the critical temperature is higher than for low temperature superconductor (LTS). HTS materials or HTS superconductors as used herein refer to superconducting materials having a critical temperature above 3 OK at zero self-field.

In a superconducting magnet, when the coils cease to be superconducting, resistance in the magnet increases. When current flows through areas with increased resistance, heat is generated. The generation of heat in an uncontrolled and undesired manner can lead to damage to the magnet. Damage can occur if magnetic energy becomes focused into small volumes and/or if large currents cause Lorenz loads to exceed allowed values. For an array of coils, structural damage can occur from unbalanced loads if some coils quench earlier than others.

The inventors have recognized that a technique for controlling quench would be advantageous. In some instances, a magnet may need to be shut down quickly, requiring it to be quenched on purpose. It is desired to shut off the magnet in a non-damaging manner by intentionally quenching the magnet. It is desired to induce quenching uniformly and quickly, without causing damage to the magnet. Not only is damage to the magnet expensive, potentially requiring replacement parts of the magnet, but damage may lead to undesirable downtime of associated equipment which uses the magnet, such as an MRI machine or a tokamak reactor.

Accordingly, systems and techniques are described herein for intentionally and rapidly inducing quench in a non-insulated magnet. The techniques described herein may be used to shut down or “turn off’ the magnet uniformly and rapidly, before damage to the magnet occurs. The inventors have recognized that aspects of the magnet itself can be leveraged to induce quench. For example, current may be changed rapidly at terminals of the magnet to cause heating. While it is typically desired to charge a superconducting magnet slowly to avoid quench, applying a rapid change in current to the magnet may facilitate intentionally inducing quench. A non-insulated magnet’s radial current flow may be exploited to provide a quench heating function, as described herein. The magnet and/or the manner in which the magnet is operated may be modified in order to enhance quench efficiency (e g., speed) and uniformity.

FIG. 1 illustrates example components of a magnet on which quench heating techniques may be implemented, in accordance with some embodiments described herein. FIG. 1 illustrates conductor paths and joint arrangements on alternating plates 102 that form a “pancake” type magnet. In the illustrated embodiment, the magnet is a grooved, plated non-insulated high-temperature superconductor (NI-HTS) winding magnet.

In the illustrated embodiment, the magnet is a stacked plate magnet comprising multiple plates 102. One or more of the plates may be electrically conductive. Although in the illustrated embodiment the magnet comprises multiple plates, in some embodiments the magnet may comprise a single plate. In addition, although in the illustrated embodiment the magnet comprises a plate having a conductor disposed thereon in a plurality of turns, other configurations for the magnet are possible. Referring to panel 3 of FIG. 1 and FIG. 3, the plate 102 of the magnet may comprise a groove 104 disposed on the surface of the plate 102 and a conductor 106 disposed within the groove 104. The conductor 106 may comprise a high temperature superconductor (HTS) such as an HTS tape stack, as shown in the illustrated embodiments. HTS tape stacks may comprise a plurality of HTS tapes arranged on top of one another along the width and length directions. An HTS tape stack may thereby have a thickness equal to (or approximately equal to) the thickness of an individual tape multiplied by the number of tapes in the stack. In some embodiments, the conductor 106 may be a composite of HTS, co-wind tapes, copper cap and solder. The conductor 106 and the groove 104 may form a plurality' of turns 110, wherein each turn extends 360 degrees around an axis that runs substantially perpendicular to the plane of the plate 102. The conductor 106 disposed on the plate 102 and the groove 104 may comprise any suitable number of turns (e.g., at least 2 turns, at least 3 turns, at least 4 turns, at least 5 turns, at least 6 turns, at least 7 turns, at least 8 turns, or any other suitable number of turns). In some embodiments, the plurality of turns 110 may form a spiral-shaped pattern.

A conductive path may enter from an exterior of the plate and/or exit the plate to an exterior of the plate. The conductive path may be formed from the conductor 106 disposed on the plate 102 and joint pads 108 which form conductive connections betw een a conductor disposed on a first plate and a second conductor formed on a second plate. The joint pads 108 may each comprise a joint formed from a conductive material. In some embodiments, the joints may be non-superconducting. In some embodiments, the joints may be formed from a material such as copper. The conductive path may extend to and/or from subsequent plates and be formed from conductor(s) and/or joint pad(s) of the subsequent plates. In some embodiments, the conductive path may enter and/or exit the plate from/to below the plate. In some embodiments, the conductive path may enter and/or exit the plate from/to above the plate. In some embodiments, the conductive path may enter and/or exit the plate laterally. As shown in FIGS. 1-3 and described herein, the magnet may comprise joint pads 108 disposed on the plate in locations where the conductive path enters or exits the plate.

As show n in the illustrated embodiment of FIG. 1, the magnet may comprise a stacked magnet comprising a plurality of structures including plates 102, also referred to herein as “pancakes.’' One or more conductors may be disposed on the respective plates in a plurality of turns for each plate. The conductors of the respective plates may be conductively connected to form a conductive path between the plates via joints disposed at joint pads, as described herein. In some embodiments, the plurality of turns may extend from an entrance joint to an exit joint in a clockwise direction. In some embodiments, the plurality of turns may extend from an entrance joint to an exit joint in a counter-clockwise direction.

The stacked magnet configuration may comprise a bottom plate. For example, plate 102 shown in panel 1 of FIG. 1 may comprise a bottom plate. The bottom plate may be disposed below other plates of the magnet and form a base for the magnet. The bottom plate 102 may comprise a joint pad 108 where the conductive path may enter the magnet at a conductive path entrance 114. The bottom plate may not comprise a groove or turns, in some embodiments (e.g.. the illustrated embodiment of panel 1 of FIG. 1). In other embodiments, the base of the magnet may comprise a bottom plate having a conductor disposed in a groove which may be formed in a plurality of turns (e.g., plate 102 illustrated in panel 3 of FIG. 1).

A magnet in the stacked magnet configuration may comprise a plurality of plates stacked together. In embodiments which include the bottom plate described herein, the plurality' of plates may be disposed above the bottom plate. In embodiments which include a top plate, as described herein, the plurality of plates may be disposed below the top plate. Each of the plurality of plates 102 may comprise respective grooves 104 arranged in a respective plurality of turns 110. For each plate 102, the conductor 106 may be disposed in the groove 104 of the plate 102 and form the plurality of turns 110 of the respective plate 102. As described herein, the conductor 106 may comprise an HTS tape stack. Each plate 102 may comprise a respective HTS tape stack. In some embodiments, the conductor may comprise a single conductor that winds through each of the plurality of plates of the magnet.

In particular, in the illustrated embodiment of FIG. 1 and FIG. 3, the magnet comprises alternating plates. Respective ones of the alternating plates may be either an ‘‘in-wind’" plate 102A or an “out-wind’" plate 102B. Whether a plate is an in-wind plate or an out-wind plate depends on the location in which the conductive path enters and exits the plate, as described herein. The conductive path may enter each plate from a lower plate disposed below the present plate in the stacked configuration and exit the plate to a higher plate disposed above the present plate in the stacked configuration (e.g., via the joints and joint pads described herein). For example, panels 3 and 7 of FIG. 1 illustrate panels with “in-wind” plates. FIG. 2A illustrates a top-side of an “in-wind” plate 102A. For an in-wind plate 102A, the conductor 106 from a low er plate joins the in- wind plate 102 A on an outer circumference of the plate at a first (entrance) j oint at out-wind j oint pad 108A. The conductor 106 winds clockwise through the plurality of turns 110 (e.g., in a spiral configuration) in the plane of the plate, and the conductor 106 exits the plate to a higher plate on the inner circumference of the plate at a second (exit) joint at in-wind joint pad 108B. Panels 5 and 9 of FIG. 1 illustrate panels with “out-wind” plates. FIG. 2C illustrates a top-side of an “out-wind” plate 102B. For an out-wind plate, the conductor 106 from a lower plate joins the out-wind plate 102B on an inner circumference of the plate at a first (entrance) joint at in-wind joint pad 108B. winds clockwise through the plurality of turns 110 (e.g., in a spiral configuration) in the plane of the plate, and the conductor 106 exits the plate to a higher plate on the outer circumference of the plate at a second (exit) joint at out-wind joint pad 108 A.

The magnet may comprise any suitable number of plates. The illustrated embodiment of FIG. 1 shows panels 1-9 and 18-20 for illustration, but it should be understood that additional plates may be inserted, or few er plates may be used than the number of plates shown in the illustrated embodiment of FIG. 1.

The stacked magnet configuration may comprise a top plate as shown in panel 19 of FIG. 1 and also in FIGS. 2E-F. FIG. 2E illustrates a top side of a top plate of the magnet. FIG. 2F illustrates a bottom side of a top plate of the magnet. The top plate may be disposed above other plates of the magnet. The top plate may comprise a joint pad 108 where the conductor 106 exits the magnet at a conductive path exit 115. The top plate may not comprise a groove or turns in some embodiments, such as in the illustrated embodiment of panel 20 of FIG. 1. In other embodiments, the top plate may be a plate comprising a conductor disposed in a groove of the plate and arranged in a plurality of turns (e.g., any of the in-wind or out-wind plates described herein). As described herein, insulation may be added betw een plates of the magnet. The bottom side of the top plate comprises insulation 112. as shown in FIG. 2F.

In some embodiments, electrically insulating material (“insulation”) may be inserted between one or more (e.g., each) of the plates of the magnet. As show n in FIGS. 2B, 2D, 2F and FIG. 1, panels 2, 4, 6, 8, 18, and 20, insulation 112 is inserted between each plate of the magnet in the illustrated embodiments. In some embodiments, the insulation 112 may comprise a cut-out 109. The cut-out 109 may serve to expose a portion of an adjacent plate. For example, as shown in FIG. 1, the insulation 112 between plates 102 comprise cut-outs 109 to expose joint pads 108 of the plates 102 to allow for the conductors 106 of the respective plates 102 to form conductive connections with conductors 106 of adjacent plates 102 via the j oint pads 108.

Referring to FIG. 2G, a cross sectional view of a stack of magnet structures 250 is shown. In particular, the magnet structures may comprise HTS pancakes of the example magnet described herein. Each pancake 252 may include a baseplate 254, which is typically formed from a conductive material such as steel. The baseplate 254 may have a groove 256 (or series of grooves) through which HTS material 258 (e.g., HTS tape) is wound. The HTS material 258 may form a superconductive path that can carry current to form a magnetic field. In embodiments, the HTS material 258 comprises a stack of HTS tapes. In embodiments, the pancakes may have a shape corresponding to a toroidal shape of a tokamak for use as toroidal field (TF) coils.

As described herein, the inventors have developed techniques for rapidly inducing quench in a non-insulated magnet. For example, the techniques described herein may facilitate inducing quench in a magnet in a controlled manner to avoid damage which may otherwise result from uncontrolled quench.

One such technique for inducing quench in a non-insulated superconducting magnet may begin by operating the non-insulated superconducting magnet by applying a first current to the non-insulated superconducting magnet. For example, the first current may be applied to terminals of the magnet such that the first current flows through the plurality of turns of the magnet. For a stacked plate magnet having multiple plates, the first current may flow through the multiple plates of the magnet (via the conductive path formed by conductor(s) and joint pad(s) of the magnet).

In some embodiments, the first current may increase and/or decrease over time. For example, the current may be a ramped current which increases over time (e.g., during a period of charging the magnet). In some embodiments, operating the non-insulated superconducting magnet may comprise operating the magnet in a “steady state’⁷ by applying an approximately constant operating current to terminals of the magnet.

Subsequent to applying the first current to the magnet, quench may be induced in the magnet at least in part by applying a second current to the non-insulated superconducting magnet. For example, the second current may be applied to terminals of the magnet such that the second current flows through the plurality of turns of the magnet. For a stacked plate magnet having multiple plates, the second current may flow through the multiple plates of the magnet (via the conductor). Application of the second cunent may cause the magnet to quench, as is further described herein.

The second current may be opposite in direction to the first current. For example, first current applied may be a positive current flowing in one direction (e.g., clockwise when referring to the circuit diagram of FIG. 12A described herein) and the second current may be a reverse current pulse flowing in the direction opposite the direction of the positive current (e.g., counterclockwise when referring to the circuit diagram of FIG. 12A). In some embodiments, the second current may be greater in magnitude than the first current (e.g., twice as large, three times as large, four times as large, etc.).

The method for inducing quench described herein, along with additional acts, are incorporated into example method 400 illustrated in FIG. 4. As shown in FIG. 4, the method 400 may begin at act 402 where a magnet (e.g., a non-insulated high-temperature superconducting magnet) is operated by applying a first current to terminals of the magnet. For example, the first current may be as previously described herein.

During normal magnet operation (e g., during act 402), a first current flow s into the plate (e.g., the conductor) via an entrance joint. As described herein, in some embodiments, the first current may comprise a steady state current (e.g., an approximately constant current) or the first current may comprise a varying current (e.g., such as a ramped current during charging of the magnet). For a stacked plate magnet, the current may enter into the plate via a terminal plate, for example, as shown in panel 20 of FIG. 1. As can be illustrated with reference to FIG. 7, for example, current enters the lower-most fin-w ind" pancake on its out- wind joint at an out-wind joint pad 108 A. Current circulates clockwise in this plate 102 through the plurality of turns 110 of the conductor 106 until it arrives at the in-wind joint pad 108B. The direction of the arrow s in FIG. 7 illustrate the direction of the current in the magnet during act 402. Current passes through the in-wind plate 102A into an out-wind plate disposed above the in- wind plate via the in-wind joint.

After exiting the in-wind plate via the in-wind joint pad, the current enters the out- wind plate via an out-wind joint pad, as illustrated in FIG. 7. Current circulates clockwise in this plate 102B through the plurality of turns 110 of the conductor 106 until it arrives at the out-wind joint pad 108 A. The direction of the arrows in FIG. 7 illustrate the direction of the cunent in the magnet during act 402. The current can then pass through the out- wind joint pad 108A into an in-wind plate disposed above the out-wind plate 102B. The alternating pattern of in-wind and out-wind plates continues to the top terminal plate where the current exits the winding pack.

The current path illustrated in FIG. 7 during act 402 produces the magnetic field and stored energy of the magnet. The generated magnetic field may have a very high inductance (e.g., approximately 11.7H). There may be low tum-to-tum resistances (e.g., approximately 20 nano-ohms). L/R times may be very long (e.g., approximately 45 hours for a magnet consisting of 3600 turns). The azimuthal current flowing in each turn may be essentially fixed. However, the magnets described herein are not limited to such parameters.

FIG. 5 illustrates an example plot 500 illustrating current applied to a non- insulated superconducting magnet over time during the example method 400 of FIG. 4. In particular, FIG. 5 illustrates the representative terminal current and average w inding waveform for an NI-HTS magnet undergoing a quench initiated by an open circuit followed by a reverse current pulse.

FIG. 6 illustrates an example plot 600 illustrating temperatures generated by the magnet over time during the example method of FIG. 4, in accordance with some embodiments of the technology⁷ described herein. During application of a first current to the magnet in act 402, the temperature of the magnet winding pack (Initial T) is relatively low⁷ as shown in FIG. 6. The applied current (I_op) during act 402, labeled in FIG. 5 as a time period A, maybe positive and in some embodiments, may be approximately fixed as shown in FIG. 5.

The method 400 may optionally proceed to act 404 where the magnet is open circuited. The magnet may be open circuited by disconnecting any power source (e.g., drive electronics shown in FIGS. 12A-C) which provides current to the terminals of the magnet. During the open circuit act, no current enters or exits the joint pads from other plates of the magnet. As shown in FIG. 5, the current applied to the magnet during the open circuit step, labeled B in plot 500 of FIG. 5, is zero.

FIG. 8 is an example diagram illustrating the path of current in anon-insulated magnet during a period where the magnet is open circuited, in accordance with some embodiments of the technology described herein. The arrows shown in FIG. 8 illustrate the direction of current flow⁷ in the in-wind and out-w⁷ind plates 102A-B of the magnet. The relative size of the arrows corresponds to a relative strength of the current at that point. As shown in FIG. 8, the total current flow in the magnet is azimuthal during act 404. A radial component of the current flows across the turns 110 to oppose the radial component of current flowing along the spiral. For in-wind plates, the azimuthal current flow is outward. For out-wind plates, the azimuthal current flow in inward

The radial current flows across the tum-to-tum resistance of the magnet as show n in FIG. 8. The tum-to-tum resistance may be based on winding spacing and resistivity of the base plate. The resultant losses in the magnet due to the current flow across the turns of the magnet, which are dictated by I²R. may intrinsically achieve intrinsic quench heating which is powered by the stored energy of the magnet. The magnet begins to heat up as a result of the increased resistance initiated by the act of open circuiting the magnet. Plot 600 of FIG. 6 illustrates the increase in temperature of the winding pack during the open circuit act.

It should be appreciated that the act of open circuiting the magnet is optional. In some embodiments, a technique for inducing quench may not include the act of open circuiting the magnet as described herein. In other embodiments, a technique may include the act of open circuiting the magnet. The inventors have recognized that the act of open circuiting the magnet may allow for increasing temperature of the winding pack more quickly, which may allow' for more efficient quenching of the magnet.

The inventors have recognized that the duration of the open circuit act may be varied. The duration of the open circuit act may be optimized to reduce the amount of energy needed when applying the rapid current pulse in act 406, described herein. For example, a longer open circuit duration may result in a larger increase in temperature of the winding pack such that the remaining temperature increase required to reach quench during the rapid current pulse act is low er. How ever, a shorter duration of the open circuit act may result in a more efficient (e.g., quicker) quench. Accordingly, the duration of the open circuit act may be optimized based on at least these factors.

The method 400 may then proceed to act 406. At act 406, a second current may be applied to terminals of the magnet. The second current may comprise a rapid current pulse. As described herein, the second current may comprise a reverse current pulse opposite in direction to a direction of the first current applied to the magnet at act 402, as shown in plot 500 of FIG. 5. Application of the second current is shown during time period C in FIG. 5. The second current may flow through the magnet in the same manner as the first current, except in a direction opposite the direction of flow of the first current. As shown in plot 600 of FIG. 6, the second current may accelerate heating of the magnet at least until the temperature of the winding pack reaches a critical temperature where quench occurs.

In some embodiments, the second current may be approximately equal in value to the first current applied at act 402. Application of the second current pulse with a magnitude that is approximately equal in value to the magnitude of the previously applied operating current achieves the quench heating function described herein. A reverse current pulse with approximately equal magnitude to operating current magnitude may increase heating of the magnet by a factor of four relative to the act of open circuiting the magnet. The inventors have recognized that a reverse current pulse with approximately equal magnitude to the operating current magnitude may be applied without any modifications to the HTS of the magnet that accommodates the operating current.

In some embodiments, the second current may have a different magnitude than a magnitude of the first current. For example, in some embodiments, the second current may be greater in magnitude than the first current (e.g., twice as large, three times as large, four times as large, etc.). FIG. 5 illustrates an example of the relative magnitudes of the first current (I_op) and the second current (IRCP).

As described herein, the duration of applying the open circuit and/or the duration of applying the second current may be optimized to balance the magnitude of the second current required to perform the quench heating function. For example, a longer open circuit increases the heat generated by the open circuit step such that less heat need be generated in the step of applying the second current. Accordingly, the duration and magnitude of acts 404-406 may be adjusted as desired (e.g., to accomplish quench in a limited amount of time). For example, in some embodiments, the magnitude of the second current is approximately 31 kA. The duration of application of the second current is on the order of seconds (e.g., less than 10 seconds, less than five seconds, between 1 and 5 seconds, etc.).

In some embodiments, the duration of the application of the open circuit and second current steps may be based on the current density in the copper co-conductor for nominal operation conditions. The intrinsic rate of temperature rise in the conductor may be a function of the current density. For the operator to control the quench (i.e., the rate of temperature rise), e.g., by application of the quench heating techniques described herein, quench must be induced faster than the intrinsic value of temperature rise in the conductor, otherwise the magnet controls how the quench will proceed instead of the operator via the quench heating techniques.

FIG. 9 is an example diagram illustrating the path of the component of current that is driven in a non-insulated magnet due to application of a rapid pulsed current applied to the terminals, in accordance with some embodiments of the technology described herein. In particular, FIG. 9 Illustrates a current pattern driven by a reverse current pulse. The current entering each plate 102A-B flows in opposite azimuthal directions along in-wind and outwind turns as shown by the arrows in FIG. 9.

As a result of the rapid current pulse applied at act 406, a portion of the current flowing across the magnet is radial. For an in-wind plate 102A, current flows from turn to turn radially outward across the plate, as indicated by the arrows shown in FIG. 9. For an out-wind plate 102B, cunent flows from turn to turn radially inward across the plate, as indicated by the arrows shown in FIG. 9. Similar to the radial current which resulted from the open circuit, the flow of current across turns 110 of the magnet generates heat due to increased resistance from tum-to-tum in the magnet. As described herein, the increase in resistance may be based on winding spacing and resistivity of the base plate. The resultant losses in the magnet due to the current flow across the turns 110 of the magnet are dictated by I²R. AS an example, when the rapid current pulse is a reverse current pulse equal to the steady state current, the radial current doubles and the I²R losses are increased by a factor of 4. In general, the total I²R dissipation scales as (IRCP + p )², limited only by the carrying capacity of the current leads and in-wind and out-wind turns of the magnet plates.

The azimuthal current flow in the in-wind plate 102A is opposite in direction to azimuthal current flow in the out-wind plate 102B. For a stacked plate magnet, significant cancellation of magnetic flux generated by these azimuthal current paths occur due to their opposite directions, reducing their inductance. The reduction in inductance allows the current pattern shown in FIG. 9 to be established rapidly, producing an azimuthally uniform radial current flow across plates in the shortest time possible

In embodiments which include performing the open circuit act prior to the application of the second current, the net current in the magnet is a superposition of the patterns in FIGS. 8-9. The superposition of the currents resulting from acts 404-406 (shown in FIGS. 8-9) results in the cancellation of steady state azimuthal current flowing at the joints of joint pads f08 of the plates 102A-B. At act 408, quench is initiated. In particular, when the critical temperature is reached, the magnet transfers its azimuthal current to the copper components of the conductor (e.g., the copper co-wind and cap). In doing so, the magnet may turn into a “copper” magnet, decaying with its characteristic L/R time and converting its stored energy into thermal energy⁷ in the magnet thereby inducing quench.

The techniques for inducing quench described herein may be performed in response to any suitable trigger. A technique for inducing quench as described herein may be initiated in response to a command from an operator, in some embodiments. For example, an operator may determine that a controlled quench of the magnet should be performed, and may provide a command to initiate a technique for inducing quench. In some embodiments, the technique for inducing quench may be initiated in response to a change in temperature in the magnet. For example, it may be desirable to intentionally induce a controlled quench of the magnet in response to a rise in temperature of the magnet. In some embodiments, a technique for intentionally inducing quench may be performed in response to a prediction of a change in temperature (e.g.. an increase in temperature). For example, a processor may run a model that predicts a rise in temperature given a current state of a system. When a temperature rise is predicted, the system may perform a technique for intentionally inducing quench of the magnet.

It should be understood that additions and/or alterations to the technique for inducing quench described herein are possible. For example, the technique described herein may be modified with one or more additions and/or alterations that may improve the quenching (e.g., in uniformity and/or speed of the quench). Example additions and alterations are further described herein.

In some embodiments, a superconducting non-insulated magnet may be constructed with one or more extensions, each of which includes a partial turn of superconducting material that extends past a terminal of a magnet. The extensions may also be referred to herein as extended portions of the conductor. As described herein, a magnet may comprise a plate having a groove forming a plurality of turns, and a conductor (e.g.. comprising superconducting material such as a HTS tape-stack) disposed in the groove in the plurality of turns. The conductor may enter and exit the plate at joints, also referred to herein as terminals. As shown in FIG. 3, for an in-wind plate 102A, the plurality of turns 110 may extend in a direction (clockwise in the illustrated embodiment) from an entrance joint on out- wind joint pad 108 A to an exit joint on in-wind joint pad 108B. A first extension 116A including a partial turn of a conductor extends past the entrance joint on out-wind joint pad 108A. For example, the first extension 116A may extend past the entrance joint on out-wind joint pad 108A in a direction opposite the plurality of turns 110 from the entrance joint to the exit joint on in-wind joint pad 108B. A second extension 116B including a partial turn of a conductor extends past the exit joint on in-wind plate 108B. The second extension 116B may extend past the exit joint on in-wind joint pad 108B in a direction opposite the plurality of turns 110 from the exit joint on the in-wind joint pad 108B to the entrance j oint on out-wind joint pad 108 A.

The inventors have recognized that providing the magnet with one or more extensions facilitates rapidly driving a large radial current across the winding pack by an external source during the intentional quenching of the magnet. The extensions provide a low inductance path for current to facilitate a rapid initiation of quench. The extensions may also facilitate distribution of current around the magnet to assist in providing a more uniform quench.

Current flow in the extended portions of the conductor during performance of a technique for intentionally inducing quench is described herein. During application of a first current to the magnet (e g., a steady state current, in some embodiments) and the open circuit of the magnet, no current flows through the extended portions 116 of the conductor. This is illustrated in FIGS. 7-8, for example. When a rapid current pulse is applied to the magnet, such as a reverse current pulse, current flows through the extended portions. The magnitude of the current in the extended portions 116 is equivalent to the applied rapid current pulse. This is shown in FIG. 9, for example.

The extended portions of the conductor may be designed to handle a particular current magnitude. For example, the extended portions may be designed, in some embodiments, to handle two times the magnitude of a steady state operating current. Accordingly, a rapid current pulse equal to two times the steady state operating current could be used with such a design without modification to other conductors of the magnet. As described herein, there is no current flowing in the extended portions during application of the first current (e.g.. during steady state operation). Accordingly, the extended portions may be operated at critical current level given the extended portions do not participate in the current path for steady state operation.

The extended portions may provide a low-inductance current path. The time it takes for current to flow through the extended portions of the conductor may be less than the time it takes for current to flow through the plurality of turns of the conductor. Accordingly, current may initially only be present in the extended portions of the conductor. The extended portions of the conductor may be disposed on opposing sides of a top face of the plate. Accordingly, the extended portions may function like a pair of opposing electrodes which induces a current flow between the electrodes. The resultant current flow in the magnet may therefore be radial (across turns of the conductor).

The current flowing in the extended portions of the conductor may vary from the value of the rapid current pulse to zero along the length of the extended portion. In some embodiments, tape grading can be employed on the extended portions, reducing their HTS stack widths from a maximum value at the joint to near zero at their ends.

As is further described herein, aspects of the extended portions may be varied. Although in the illustrated embodiments, the extended portions comprise approximately half a turn in length, other lengths are possible. For example, the extended portions may comprise approximately one quarter of a turn.

In the illustrated embodiments, the extended portions on a respective plate are equal in length. In other embodiments, the respective extended portions on a plate may have different lengths. In addition, respective extended portions on different plates of the magnet may have different lengths.

In the illustrated embodiments, the joint pads of the magnet plate are diametrically opposed. Accordingly, the extended portions are disposed on opposite sides of a top face of the plate. However, in other embodiments, the extended portions may be disposed in different locations other than on opposite sides of the top face of the plate.

FIGS. 10A-H illustrate alternative conductor and joint arrangements to facilitate inducing quench, in accordance with some embodiments of the technology described herein. FIGS. 10A-H illustrate possible embodiments of winding and joint arrangements of a magnet on which the techniques for intentionally inducing quench may be applied. The azimuthal locations of the in-wind and out-wind j oints vary in the embodiments illustrated in FIGS. 10A-H. FIG. 10A illustrates the configuration of joint pads shown in FIG. 1 and described herein. FIGS. 10B-D and FIGS. 10F-G illustrate arrangements where the azimuthal locations of in-wind and out-wind joint pads are varied relative to the embodiments previously described herein (e.g., being disposed in different regions of the plate, for example, not on a same side of the plate). FIGS. 10A-D illustrate embodiments using extended portions having a length of approximately ! of a turn. FIGS. 10E-H implement separate c-shaped ring conductors that pass through joints of the plates. The inventors have recognized that these c-shaped ring conductors may provide an advantage in some instances, such as in designs for very large magnitude reverse current pulses. The separate C-shaped ring conductor designs may be best suited for tape-on-tape windings and hybrid winding schemes.

Portions of the conductor and joint arrangements shown in FIGS. 10A-H and FIGS. 11 A-H are labeled to illustrate how current is moving in the conductor. During application of a short pulse, portions of the conductor shown in orange (labeled ”0") behave electrically as if they are not participating at all due to the large inductance of these portions which make changing current in these portions of the conductor difficult. The current in these portions is essentially fixed despite the fact that voltage may vary along the winding.

For a current pulse driven by applying voltage to the terminals of the conductor, portions of the conductor shown in cyan (labeled “C’) are at a positive potential while portions of the conductor shown in purple (labeled “P”) are at a negative potential. A pattern of radial current flowing from the cyan portions to purple portions is shown in FIGS. 10A-H and FIGS. 11A-H. The conductor configurations shown in FIGS. 10A-H produce azimuthally uniform radial current flow while the conductor configurations shown in FIGS. 11 A-H do not have azimuthally uniform radial current flow.

FIGS. 11A-H show additional variants of the technology described herein, including components that provide for partial quench heating. In the embodiments illustrated in FIGS. 11 A-H, the extended portions of the conductor on the in- wind and out- wind joints are truncated in the embodiments shown in FIGS. 11A-D (e.g., one or both of the extended portions do not fully extend half-way around the plate and the lengths of one or both of the extended portions is less than half a turn, for example, having a length of ^lA of a turn instead). The embodiments shown in FIGA. 11B-D are truncated differently at an in- wind joint relative to the out-wind joint.

The inventors have recognized that the embodiments illustrated in FIGS. 11 A-H may have drawbacks in efficiency relative to half-turn arrangements of the extended portions, however, these embodiments may have other advantages. For example, in the illustrated embodiment of FIG. 11 A, the extended portions only extend A of the way around on the in-wind and out- wind joints, and therefore the radial width of the baseplate can be reduced in the ‘A portion that is opposite to the joint pads. The azimuthal distribution of radial currents driven by the rapid (reverse, in some embodiments) current pulse will be affected by the length and arrangement of the extended turns, which may cause non-uniform heating of the baseplate. In some instances, this could be advantageous to compensate for azimuthal variation in thermal margin of the HTS. In some instances, it may be desirable to initiate quench first in a broad azimuthal zone that includes the joint pads.

FIGS. 11E-H show arrangements for C-shaped ring conductors on the in-wind and out-wind joints similar to the arrangements shown in FIGS. 10E-H.

The techniques for inducing quench described herein may be facilitated via use of the circuit of FIGS. 12A-C. FIGS. 12A-C illustrate examples of control circuitry 1200 with a no-insulation magnet, in accordance with some embodiments of the technology’ described herein. As shown in FIGS. 12A-C, a power supply (e.g., forming part of the drive electronics 1204) sources a current (which may be referred to as a “transport current’') to an NI magnet. The NI magnet may include a superconducting coil 1206 having electrical terminals for coupling to a power supply, wherein receipt of a current from the power supply through the electrical terminals causes the superconducting coil 1206 to generate a magnetic field. FIG. 12A illustrates the example control circuitry’ 1200 during application of a first current (e.g., during steady state conditions, such as act 402 of example method 400). In this state, the drive electronics provide a first current that flows through the magnet. In an operating state of the NI magnet (e.g., steady state, or a charging state), for example, as shown in FIG. 12A, the switch(es) 1208, controlled by at least one processor 1202, may be closed to allow’ the current to reach the magnet. As described herein, the NI magnet can be open-circuited. FIG. 12B illustrates the example control circuitry 1200 during open circuiting of the circuit (e.g., act 404 of example method 400). To accomplish the open circuiting and rapidly drive the transport current sourced by the power supply down to zero, the switch(es) 1208 may' be opened by providing a control signal (e.g., using a processor 1202) to the switch(es) 1208 that opens the switch. Current no longer flows from the drive electronics 1204. Current remaining in the magnet flows across the turns of the coil 1206, where there is no insulation, as shown in FIG. 12B. FIG. 12C illustrates the example control circuitry’ 1200 during application of a second current (e.g., act 406 of example method 400). In this operation, a second current is applied from the drive electronics 1204 in a direction opposite the flow of the first current. The second current flows across turns of the coil 1206, where there is no insulation, as shown in FIG. 12C.

As used herein, a non-insulated magnet, also referred to herein as a no-insulation magnet, includes a magnet having a conductor arranged in a plurality turns and an electrical resistance between a first turn and second turn of the plurality of turns is no more than 1 megaohm (e.g., greater than 0 and less than 1 megaohm, greater than 0 and less than .75 megaohms, greater than 0 and less than .5 megaohms, greater than 0 and less than .25 megaohms, greater than 0 and less than .1 megaohms). Additionally, while anon- insulated magnet may have little to no electrical resistance between turns of an individual magnet plate, in some cases electrical insulation may be positioned in other locations within a non-insulated magnet. For example, electrical insulation may be placed between respective plates of the magnet, as described above. Accordingly, the language '‘noninsulated,” ‘'no-insulation,” “NI” and the like in reference to a magnet refers to a low electrical resistance between respective turns, and does not preclude other regions of the magnet from being wholly or partially electrically insulated from one another.

Example embodiments of the technology described herein are provided below:

(1) A method for inducing quench in a non-insulated superconducting magnet, the method comprising: operating the non-insulated superconducting magnet by applying a first current to the non-insulated superconducting magnet; and inducing quench in the noninsulated superconducting magnet at least in part by applying a second current to the noninsulated superconducting magnet, wherein the second current is opposite in direction to the first current.

(2) The method of (1), wherein the second current has a magnitude that is greater than a magnitude of the first current.

(3) The method of (2), wherein the magnitude of the second current is at least twice the magnitude of the first current.

(4) The method of any of ( 1 )-(3), wherein the method further comprises, subsequent to applying the first current to the non-insulated superconducting magnet and prior to applying the second current to the non-insulated superconducting magnet, open circuiting the non-insulated superconducting magnet.

(5) The method of any of (1 )-(4), wherein the second current is applied to the noninsulated superconducting magnet such that a radial current in the non-insulated superconducting magnet is induced. (6) The method of any of ( 1 )-(5), wherein the non-insulated superconducting magnet comprises a plurality of turns, and when the first current is applied to the noninsulated superconducting magnet, a resistance between respective turns of the plurality of turns is less than 1 megaohm.

(7) The method of any of ( 1 )-(6), wherein the applying the second current to the non-insulated superconducting magnet is performed by control circuitry for the noninsulated superconducting magnet in response to the control circuitry receiving a command to shut down the non-insulated superconducting magnet or making a determination to shut dow n the non-insulated superconducting magnet.

(8) The method of any of ( 1 )-(7), wherein the non-insulated superconducting magnet comprises a high temperature superconductor.

(9) The method of (8), wherein the non-insulated superconducting magnet comprises a first electrically conductive plate having a first groove and a first high- temperature superconductor (HTS) tape stack comprising a first plurality' of turns disposed in the first groove and wherein a resistance between respective ones of the first plurality of turns of the first HTS tape stack is less than one megaohm when the first current is applied to the non-insulated superconducting magnet.

(10) The method of (9), wherein the non-insulated superconducting magnet further comprises a second electrically conductive plate having a second groove and a second HTS tape stack comprising a second plurality’ of turns disposed in the second groove, and wherein the first HTS tape stack forms an electrically conductive connection with the second HTS tape stack.

(11) The method of (10), wherein the non-insulated superconducting magnet comprises a plurality of electrically conductive plates including the first electrically conductive plate and the second electrically conductive plate and the plurality of electrically conductive plates are arranged in a stacked configuration.

(12) The method of (11), wherein: the non-insulated superconducting magnet comprises a conductor comprising the first HTS tape stack and the second HTS tape stack; the conductor enters the second electrically conductive plate from the first electrically conductive plate at a first point on the second electrically conductive plate, the first electrically conductive plate being disposed belo v the second electrically conductive plate in the stacked configuration; the conductor exits the second electrically conductive plate to a third electrically conductive plate of the plurality of electrically conductive plates at a second point on the second electrically conductive plate, the third electrically conductive plate being disposed above the second electrically conductive plate in the stacked configuration; the second plurality of turns of the second electrically conductive plate extends from the first point to the second point; at the first point, the conductor comprises a first extended portion that extends in a direction opposite a direction in which the second plurality of turns extends from the first point to the second point; and at the second point, the conductor comprises a second extended portion that extends in a direction opposite a direction in which the second plurality of turns extend from the second point to the first point.

(13) The method of (11), wherein the non-insulated superconducting magnet further comprises electrically insulating material between adjacent plates of the plurality of electrically conductive plates.

(14) A system for inducing quench in a non-insulated superconducting magnet, the system comprising: the non-insulated superconducting magnet; and a controller configured to: operate the magnet by applying a first current to the non-insulated superconducting magnet; and induce quench in the magnet at least in part by applying a second current to the magnet, wherein the second current is opposite in direction to the first current.

(15) The system of (14), wherein the second current has a magnitude that is greater than a magnitude of the first current.

(16) The system of (15), wherein the magnitude of the second current is at least twice the magnitude of the first current.

(17) The system of any of (14)-(16), wherein the controller is further configured to, subsequent to applying the first current to the non-insulated superconducting magnet and prior to applying the second current to the non-insulated superconducting magnet, open circuit the non-insulated superconducting magnet.

(18) The system of any of (14)-(17), wherein the controller is configured to apply the second current to the non-insulated superconducting magnet such that a radial current in the non-insulated superconducting magnet is induced.

(19) The system of any of ( 14)-( 18), wherein the non-insulated superconducting magnet comprises a plurality of turns, and when the first current is applied to the noninsulated superconducting magnet, a resistance between respective turns of the plurality of turns is less than 1 megaohm. (20) The system of any of (14)-(19), further comprising control circuitry configured to apply the second cunent to the non-insulated superconducting magnet, wherein the control circuitry is configured to apply the second current to the non-insulated superconducting magnet in response to receiving a command to shut down the noninsulated superconducting magnet or making a determination to shut down the noninsulated superconducting magnet.

(21) The system of any of (14)-(20), wherein the non-insulated superconducting magnet comprises a high temperature superconductor.

(22) The system of (21), wherein the non-insulated superconducting magnet comprises a first electrically conductive plate having a first groove and a first high- temperature superconductor (HTS) tape stack comprising a first plurality of turns disposed in the first groove and wherein the first resistance between respective ones of the first plurality of turns of the first HTS tape stack is less than one megaohm when the first current is applied to the non-insulated superconducting magnet.

(23) The system of (22), wherein the non-insulated superconducting magnet further comprises a second electrically conductive plate having a second groove and a second HTS tape stack comprising a second plurality of turns disposed in the second groove, and where the first HTS tape stack forms an electrically conductive connection with the second HTS tape stack.

(24) The system of (23), wherein the non-insulated superconducting magnet comprises a plurality of electrically conductive plates including the first electrically conductive plate and the second electrically conductive plate and the plurality⁷ of electrically conductive plates are arranged in a stacked configuration.

(25) The system of (24), wherein: the non-insulated superconducting magnet comprises a conductor comprising the first HTS tape stack and the second HTS tape stack; the conductor enters the second electrically conductive plate from the first electrically conductive plate at a first point on the second electrically conductive plate, the first electrically conductive plate being disposed below the second electrically conductive plate in the stacked configuration; the conductor exits the second electrically conductive plate to a third electrically conductive plate of the plurality of electrically conductive plates at a second point on the second electrically conductive plate, the third electrically conductive plate being disposed above the second electrically conductive plate in the stacked configuration; the second plurality of turns of the second electrically conductive plate extends from the first point to the second point; at the first point, the conductor comprises a first extended portion that extends in a direction opposite a direction in which the second plurality of turns extends from the first point to the second point; and at the second point the conductor comprises a second extended portion that extends in a direction opposite a direction in which the second plurality of turns extend from the second point to the first point.

(26) The system of (24), wherein the non-insulated superconducting magnet further comprises electrically insulating material between adjacent plates of the plurality of electrically conductive plates.

(27) A superconducting non-insulated magnet, comprising: a plate; a plurality of turns of superconducting material within a groove of the plate, the plurality of turns extending from a first terminal at which a first electrical connection extends to an exterior of the plate and a second terminal at which a second electrical connection extends to the exterior of the plate; a first extension including a first partial turn of the superconducting material extending past the first terminal: and a second extension including a second partial turn of the superconducting material extending past the second terminal.

(28) The superconducting non-insulated magnet of (27), wherein the first and second extensions are approximately equal in length.

(29) The superconducting non-insulated magnet of any of (27)-(28), wherein the first and second extensions differ in length.

(30) The superconducting non-insulated magnet of any of (27)-(29), wherein the superconducting material is arranged in a spiral configuration comprising the plurality of turns, and the first and second extensions each have a length of approximately half of a turn of the plurality of turns.

(31) The superconducting non-insulated magnet of any of (27)-(30), wherein the first and second extensions each have a length of approximately one quarter of a length of a turn of the plurality of turns.

(32) The superconducting non-insulated magnet of any of (27)-(31), wherein the first and second terminals are disposed on opposite sides of a top face of the plate.

(33) The superconducting non-insulated magnet of any of (27)-(32), wherein the first extension differs in width along a length of the first extension and the second extension differs in width along a length of the second extended portion. (34) The superconducting non-insulated magnet of claim of any of (27)-(33), further comprising a plurality of plates, the plurality of plates including the plate.

(35) The superconducting non-insulated magnet of (34), wherein the plurality of plates are arranged in a stacked configuration.

(36) The superconducting non-insulated magnet of (35), further comprising insulation disposed between adjacent ones of the plurality of plates.

(37) The superconducting non-insulated magnet of (34), wherein the plurality of plates comprise at least 10 plates.

(38) The superconducting non-insulated magnet of (34), wherein the plurality of plates comprise at least 20 plates.

(39) A system comprising the superconducting non-insulated magnet of any of (27)-(38) and a controller configured to operate the superconducting non-insulated magnet by applying a first current to the superconducting non-insulated magnet.

(40) The system of (39) wherein when the controller applies the first current to the superconducting non-insulated magnet, no current flows through the first and second extensions.

(41) The system of (40), wherein the controller is further configured to induce quench in the superconducting non-insulated magnet at least in part by applying a second current to the magnet, and wherein the second current differs from the first current in that the second current is greater in magnitude than the first current and/or is opposite in direction to the first current.

Having thus described several aspects and embodiments of the technology set forth in the disclosure, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be within the spirit and scope of the technology described herein. For example, those of ordinary skill in the art will readily envision a variety⁷ of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the embodiments described herein. Aspects described in one embodiment may be combined in any manner with aspects described in other embodiments. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described. In addition, any combination of two or more features, systems, articles, materials, kits, and/or methods described herein, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the scope of the present disclosure.

The above-described embodiments can be implemented in any of numerous ways. One or more aspects and embodiments of the present disclosure involving the performance of processes or methods may utilize program instructions executable by a device (e.g., a computer, a processor, or other device) to perform, or control performance of, the processes or methods. In this respect, various inventive concepts may be embodied as a non-transitory computer readable storage medium (or multiple computer readable storage media) (e.g., a computer memory, one or more floppy discs, compact discs, optical discs, magnetic tapes, flash memories, circuit configurations in Field Programmable Gate Arrays or other semiconductor devices, or other tangible computer storage medium) encoded with one or more programs that, when executed on one or more computers or other processors, perform methods that implement one or more of the various embodiments described above. The computer readable medium or media can be transportable, such that the program or programs stored thereon can be loaded onto one or more different computers or other processors to implement various ones of the aspects described above.

The terms “program” or “software” are used herein in a generic sense to refer to any type of computer code or set of computer-executable instructions that can be employed to program a computer or other processor to implement various aspects as described above. Additionally, it should be appreciated that according to one aspect, one or more computer programs that when executed perform methods of the present disclosure need not reside on a single computer or processor, but may be distributed in a modular fashion among a number of different computers or processors to implement various aspects of the present disclosure.

Computer-executable instructions may be in many forms, such as program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Typically the functionality' of the program modules may be combined or distributed as desired in various embodiments.

Also, data structures may be stored in computer-readable media in any suitable form. For simplicity' of illustration, data structures may be shown to have fields that are related through location in the data structure. Such relationships may likewise be achieved by assigning storage for the fields with locations in a computer-readable medium that convey relationship between the fields. However, any suitable mechanism may be used to establish a relationship between information in fields of a data structure, including through the use of pointers, tags or other mechanisms that establish relationship between data elements.

The above-described embodiments of the present technology can be implemented in any of numerous ways. For example, the embodiments may be implemented using hardw are, softw are or a combination thereof. When implemented in software, the softw are code can be executed on any suitable processor or collection of processors, whether provided in a single computer or distributed among multiple computers. It should be appreciated . that any component or collection of components that perform the functions described above can be generically considered as a controller that controls the abovedescribed function. A controller can be implemented in numerous ways, such as with dedicated hardw are, or with general purpose hardw are (e.g., one or more processor) that is programmed using microcode or software to perform the functions recited above, and may be implemented in a combination of ways when the controller corresponds to multiple components of a system.

Further, it should be appreciated that a computer may be embodied in any of a number of forms, such as a rack-mounted computer, a desktop computer, a laptop computer, or a tablet computer, as non-hmiting examples. Additionally, a computer may be embedded in a device not generally regarded as a computer but with suitable processing capabilities, including a Personal Digital Assistant (PDA), a smartphone or any other suitable portable or fixed electronic device.

Also, a computer may have one or more input and output devices. These devices can be used, among other things, to present a user interface. Examples of output devices that can be used to provide a user interface include printers or display screens for visual presentation of output and speakers or other sound generating devices for audible presentation of output. Examples of input devices that can be used for a user interface include keyboards, and pointing devices, such as mice, touch pads, and digitizing tablets. As another example, a computer may receive input information through speech recognition or in other audible formats.

Such computers may be interconnected by one or more networks in any suitable form, including a local area network or a wide area network, such as an enterprise network, and intelligent network (IN) or the Internet. Such networks may be based on any suitable technology and may operate according to any suitable protocol and may include wireless networks, wired networks or fiber optic networks.

Also, as described, some aspects may be embodied as one or more methods. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though show n as sequential acts in illustrative embodiments.

All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinarymeanings of the defined terms.

The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. Thus, as anon-limiting example, a reference to “A and/or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every' element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as anon- limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and/or B”) can refer, in one embodiment, to at least one. optionally including more than one. A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

Also, the phraseology⁷ and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having," “containing.” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carry ing,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively.

The terms “substantially”, “approximately”, and “about” may be used to mean within ±20% of a target value in some embodiments, within ±10% of a target value in some embodiments, within ±5% of a target value in some embodiments, within ±2% of a target value in some embodiments. The terms “approximately” and “about” may include the target value.

Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

Claims

1. A method for inducing quench in a non-insulated superconducting magnet, the method comprising: operating the non-insulated superconducting magnet by applying a first current to the non-insulated superconducting magnet; and inducing quench in the non-insulated superconducting magnet at least in part by applying a second current to the non-insulated superconducting magnet, wherein the second current is opposite in direction to the first current.

2. The method of claim 1, wherein the second current has a magnitude that is greater than a magnitude of the first current.

3. The method of claim 2, wherein the magnitude of the second current is at least twice the magnitude of the first current.

4. The method of any of claims 1-3, wherein the method further comprises, subsequent to applying the first current to the non-insulated superconducting magnet and prior to applying the second current to the non-insulated superconducting magnet, open circuiting the non-insulated superconducting magnet.

5. The method of any of claims 1-4, wherein the second current is applied to the noninsulated superconducting magnet such that a radial current in the non-insulated superconducting magnet is induced.

6. The method of any of claims 1-5, wherein the non-insulated superconducting magnet comprises a plurality of turns, and when the first current is applied to the noninsulated superconducting magnet, a resistance between respective turns of the plurality of turns is less than 1 megaohm.

7. The method of any of claims 1-6, wherein the applying the second current to the non-insulated superconducting magnet is performed by control circuitry for the noninsulated superconducting magnet in response to the control circuitry receiving a command to shut down the non-insulated superconducting magnet or making a determination to shut down the non-insulated superconducting magnet.

8. The method of any of claims 1-7, wherein the non-insulated superconducting magnet comprises a high temperature superconductor.

9. The method of claim 8, wherein the non-insulated superconducting magnet comprises a first electrically conductive plate having a first groove and a first high- temperature superconductor (HTS) tape stack comprising a first plurality’ of turns disposed in the first groove and wherein a resistance between respective ones of the first plurality of turns of the first HTS tape stack is less than one megaohm when the first current is applied to the non-insulated superconducting magnet.

10. The method of claim 9, wherein the non-insulated superconducting magnet further comprises a second electrically conductive plate having a second groove and a second HTS tape stack comprising a second plurality’ of turns disposed in the second groove, and wherein the first HTS tape stack forms an electrically conductive connection with the second HTS tape stack.

11. The method of claim 10, wherein the non-insulated superconducting magnet comprises a plurality of electrically’ conductive plates including the first electrically conductive plate and the second electrically conductive plate and the plurality’ of electrically conductive plates are arranged in a stacked configuration.

12. The method of claim 11, wherein: the non-insulated superconducting magnet comprises a conductor comprising the first HTS tape stack and the second HTS tape stack; the conductor enters the second electrically conductive plate from the first electrically conductive plate at a first point on the second electrically conductive plate, the first electrically conductive plate being disposed below the second electrically conductive plate in the stacked configuration; the conductor exits the second electrically conductive plate to a third electrically conductive plate of the plurality' of electrically conductive plates at a second point on the second electrically conductive plate, the third electrically conductive plate being disposed above the second electrically conductive plate in the stacked configuration; the second plurality of turns of the second electrically conductive plate extends from the first point to the second point; at the first point, the conductor comprises a first extended portion that extends in a direction opposite a direction in which the second plurality of turns extends from the first point to the second point; and at the second point, the conductor comprises a second extended portion that extends in a direction opposite a direction in which the second plurality' of turns extend from the second point to the first point.

13. The method of claim 11, wherein the non-insulated superconducting magnet further comprises electrically insulating material between adjacent plates of the plurality of electrically conductive plates.

14. A system for inducing quench in a non-insulated superconducting magnet, the system comprising: the non-insulated superconducting magnet; and a controller configured to: operate the magnet by applying a first current to the non-insulated superconducting magnet; and induce quench in the magnet at least in part by applying a second current to the magnet, wherein the second current is opposite in direction to the first current.

15. The system of claim 14, wherein the second current has a magnitude that is greater than a magnitude of the first current.

16. The system of claim 15. wherein the magnitude of the second current is at least twice the magnitude of the first current.

17. The system of any of claims 14-16, wherein the controller is further configured to, subsequent to applying the first current to the non-insulated superconducting magnet and prior to applying the second current to the non-insulated superconducting magnet, open circuit the non-insulated superconducting magnet.

18. The system of any of claims 14-17, wherein the controller is configured to apply the second current to the non-insulated superconducting magnet such that a radial current in the non-insulated superconducting magnet is induced.

19. The system of any of claims 14-18. wherein the non-insulated superconducting magnet comprises a plurality of turns, and when the first current is applied to the noninsulated superconducting magnet, a resistance between respective turns of the plurality' of turns is less than 1 megaohm.

20. The system of any of claims 14-19, further comprising control circuitry configured to apply the second current to the non-insulated superconducting magnet, wherein the control circuitry is configured to apply the second current to the non-insulated superconducting magnet in response to receiving a command to shut down the noninsulated superconducting magnet or making a determination to shut down the noninsulated superconducting magnet.

21. The system of any of claims 14-20, wherein the non-insulated superconducting magnet comprises a high temperature superconductor.

22. The system of claim 21, wherein the non-insulated superconducting magnet comprises a first electrically conductive plate having a first groove and a first high- temperature superconductor (HTS) tape stack comprising a first plurality of turns disposed in the first groove and wherein the first resistance between respective ones of the first plurality⁷ of turns of the first HTS tape stack is less than one megaohm when the first current is applied to the non-insulated superconducting magnet.

23. The system of claim 22, wherein the non-insulated superconducting magnet further comprises a second electrically conductive plate having a second groove and a second HTS tape stack comprising a second plurality’ of turns disposed in the second groove, and where the first HTS tape stack forms an electrically conductive connection with the second HTS tape stack.

24. The system of claim 23, wherein the non-insulated superconducting magnet comprises a plurality of electrically conductive plates including the first electrically conductive plate and the second electrically conductive plate and the plurality of electrically conductive plates are arranged in a stacked configuration.

25. The system of claim 24, wherein: the non-insulated superconducting magnet comprises a conductor comprising the first HTS tape stack and the second HTS tape stack; the conductor enters the second electrically conductive plate from the first electrically conductive plate at a first point on the second electrically conductive plate, the first electrically conductive plate being disposed below the second electrically conductive plate in the stacked configuration; the conductor exits the second electrically conductive plate to a third electrically conductive plate of the plurality of electrically conductive plates at a second point on the second electrically conductive plate, the third electrically conductive plate being disposed above the second electrically conductive plate in the stacked configuration; the second plurality of turns of the second electrically conductive plate extends from the first point to the second point; at the first point, the conductor comprises a first extended portion that extends in a direction opposite a direction in which the second plurality of turns extends from the first point to the second point; and at the second point, the conductor comprises a second extended portion that extends in a direction opposite a direction in which the second plurality of turns extend from the second point to the first point.

26. The system of claim 24, wherein the non-insulated superconducting magnet further comprises electrically insulating material between adjacent plates of the plurality of electrically conductive plates.

27. A superconducting non-insulated magnet, comprising: a plate; a plurality of turns of superconducting material within a groove of the plate, the plurality of turns extending from a first terminal at which a first electrical connection extends to an exterior of the plate and a second terminal at which a second electrical connection extends to the exterior of the plate; a first extension including a first partial turn of the superconducting material extending past the first terminal; and a second extension including a second partial turn of the superconducting material extending past the second terminal.

28. The superconducting non-insulated magnet of claim 27, wherein the first and second extensions are approximately equal in length.

29. The superconducting non-insulated magnet of any of claims 27-28, wherein the first and second extensions differ in length.

30. The superconducting non-insulated magnet of any of claims 27-29, wherein the superconducting material is arranged in a spiral configuration comprising the plurality of turns, and the first and second extensions each have a length of approximately half of a turn of the plurality of turns.

31. The superconducting non-insulated magnet of any of claims 27-30, wherein the first and second extensions each have a length of approximately one quarter of a length of a turn of the plurality of turns.

32. The superconducting non-insulated magnet of any of claims 27-31, wherein the first and second terminals are disposed on opposite sides of a top face of the plate.

33. The superconducting non-insulated magnet of any of claims 27-32, wherein the first extension differs in width along a length of the first extension and the second extension differs in width along a length of the second extension.

34. The superconducting non-insulated magnet of any of claims 27-33, further comprising a plurality of plates, the plurality of plates including the plate.

35. The superconducting non-insulated magnet of claim 34, wherein the plurality of plates are arranged in a stacked configuration.

36. The superconducting non-insulated magnet of claim 35, further comprising insulation disposed between adjacent ones of the plurality of plates.

37. The superconducting non-insulated magnet of claim 34, wherein the plurality of plates comprise at least 10 plates.

38. The superconducting non-insulated magnet of claim 34, wherein the plurality of plates comprise at least 20 plates.

39. A system comprising the superconducting non-insulated magnet of any of claims 27-38 and a controller configured to operate the superconducting non-insulated magnet by applying a first current to the superconducting non-insulated magnet.

40. The system of claim 39, wherein when the controller applies the first current to the superconducting non-insulated magnet, no current flows through the first and second extensions.

41. The system of claim 40, wherein the controller is further configured to induce quench in the superconducting non-insulated magnet at least in part by applying a second current to the magnet, and wherein the second current differs from the first current in that the second current is greater in magnitude than the first current and/or is opposite in direction to the first current.