Dipole field magnet

Abstract

A dipole field magnet includes an internal volume shielded from a magnetic field of the magnet due to a current flowing in the magnet. The dipole field magnet may include a plurality of annular superconductor coils configured to shield an interior volume between the annular superconductor coils from a magnetic field of the dipole field magnet. The dipole field magnets may form part of fusion reactors and / or magnetic torques and / or other dipole field magnet applications. In some cases, the dipole field magnet may include a plurality of annular superconductor coils configured to shield an interior volume between the coils from a magnetic field and / or the dipole field magnet may create a low field region in the interior volume.

Description

Technical Field

[0001] This disclosure generally relates to methods for shielding the volume and magnetic field in a dipole field magnet. This disclosure partially relates to dipole field magnets for fusion reactors, wherein an internal volume can be shielded to allow current-driven devices to operate within the internal volume. Background Technology

[0002] Suspended dipole reactors use suspended superconducting magnets to create a high magnetic field around the magnet. This high magnetic field is configured to confine the plasma. The concept was first theoretically developed by Akira Hasegawa in 1987. Under the right conditions, the magnet can confine the plasma hot enough to achieve nuclear fusion, thus forming a fusion reactor.

[0003] The Massachusetts Institute of Technology (MIT) and Columbia University jointly led the Suspended Dipole Experiment (LDX) to develop a prototype suspended dipole reactor using a low-temperature superconductor (LTS) (Nb3Sn LTS). They demonstrated successful levitation of their dipole field magnets and characterized the plasmas they confined in various configurations. The device uses a free-floating dipole field magnet in the shape of a toroid or ring. The magnet initially has two anti-rotating LTS superconducting coils, subsequently multiple coils clamped together to form a single toroidal winding configured to carry current when superconducting. The magnet is placed in a vacuum chamber, where optional Helmholtz coils are used at the chamber's edges to generate and / or control the magnetic field. The magnet is charged using induction, and a physical support is used to raise it to the center of the chamber. The dipole field magnet is then suspended using an external field, and an external microwave system is used to generate plasma around the dipole field magnet. Due to the superconducting materials used and the system architecture, the Suspended Dipole Experiment and its LTS superconductor are not suitable for fusion-related fields or high-temperature superconductors (HTS).

[0004] The University of Tokyo used the Ring Trap-1 project to further understand dipole confinement and used HTS (Bi-2223HTS) to improve the performance of suspended dipoles. However, due to the HTS material used, the Ring Trap-1 project is not scalable to fusion reactors.

[0005] Figure 1 A cross-section of one side of the magnet used in the LDX system is shown. A helium container, configured to be cooled to the LTS operating temperature, is supported inside a small vacuum container. Inside the helium pressure vessel, a magnet winding group, formed by multiple coils clamped together to form a winding group, is shaped to extend the LTS volume around the magnet. In use, the magnet winding group will be superconducting and carry currents up to 2300 A.

[0006] Previous levitation dipole reactors have not been further developed. One challenge is powering or driving the current within the high-temperature superconducting magnet. The object of this invention is to describe a dipole field magnet, for example, for levitation dipole reactors, which substantially alleviates the aforementioned product limitations or at least provides an alternative. Summary of the Invention

[0007] Existing technologies provide dipole field magnets. However, it is advantageous to improve dipole field magnets to allow their use to be scaled up to fusion reactor environments and operated with suitable superconducting materials, and / or to improve the overall performance of dipole field magnets.

[0008] In a first aspect, the invention can be broadly described as including a dipole field magnet comprising: a plurality of toroidal superconducting coils configured to shield the internal volume between the toroidal superconducting coils from the magnetic field of the dipole field magnet. The toroidal superconducting coils may be positioned or arranged relative to each other such that the current flowing through the superconducting coils generates a low-field region in the internal volume, thereby effectively shielding the internal volume from the magnetic field.

[0009] In some cases, the internal volume is ring-shaped. In some cases, the internal volume is toroidal. In some cases, the superconducting coils are coaxial. In some cases, the superconducting coils are axially spaced. In some cases, the internal volume extends between coils with smaller diameters and coils with larger diameters. In some cases, at least two coils have the same cross-sectional dimensions. In some cases, multiple coils have the same height. In some cases, multiple coils are symmetrical above and below the radial plane. In some cases, the coil with the larger volume is positioned towards the inner periphery of the magnet compared to the outer periphery. In some cases, the multiple coils include at least four coils. In some cases, the superconducting coil includes resistance junctions or connections.

[0010] In some cases, multiple coils are configured to carry current in the same direction. In some cases, the magnetic field of the dipole magnet is generated by current flowing in a toroidal superconducting coil. In some cases, the coils are set and / or configured by their position and / or orientation. In some cases, the multiple coils form a substantially circular and / or elliptical cross-section. In some cases, at least two of the multiple coils are spaced apart. In some cases, the coils are spaced apart by spacers. In some cases, the superposition of currents in the individual coils of the multiple coils shields or reduces the magnetic field region within the internal volume.

[0011] In some cases, each coil in a plurality of coils comprises a plurality of superconducting layers. In some cases, each coil in a plurality of coils comprises a plurality of turns, each turn comprising a plurality of superconducting layers. In some cases, the turns and / or layers are each arranged in the same orientation. In some cases, the turns and / or layers are radially oriented. In some cases, the turns and / or layers are separated by spacer layers. In some cases, the turns and / or layers are separated by support layers. In some cases, the thickness of the spacer layers and / or support layers is variable among the different coils. In some cases, the superconductor comprises at least one of superconducting strips and superconducting wires. In some cases, the superconductor comprises a high-temperature superconductor. In some cases, the cross-section of each coil in a plurality of coils is substantially rectangular.

[0012] In some cases, a device is included within an internal volume. In some cases, the device is for driving current in multiple coils. In some cases, the device inductively charges superconducting coils. In some cases, the device includes a flux pump. In some cases, a magnetic field shield is included between the multiple coils and the internal volume. In some cases, the magnetic field shield comprises a ferromagnetic material, optionally iron. In some cases, the magnetic field shield is configured to reduce inductive coupling between coils on opposite sides of the magnetic field shield. In some cases, the magnetic field shield has a variable thickness, optionally configured to be thicker in high-field regions during use. In some cases, the magnetic field shield and the multiple coils are configured to work together to shield the internal volume between the toroidal superconducting coils from the magnetic field of a dipole magnet.

[0013] In some cases, the device includes a housing surrounding multiple coils. In some cases, the device includes a magnetically sensitive element. In some cases, the device includes an iron core. In some cases, the shielding is sufficient to prevent at least one of the magnetically sensitive element and the iron core from saturating.

[0014] In another aspect, the invention may be broadly described as including a reactor chamber comprising a dipole field magnet as described herein and / or in other aspects.

[0015] In some cases, this includes: a vacuum container; and a levitation device for levitizing the dipole field magnet. In some cases, the reactor chamber is configured to generate plasma between the outer periphery of the magnet and the inner wall of the reactor chamber.

[0016] In another aspect, the invention may be broadly described as including a dipole field magnet comprising: a plurality of toroidal superconducting coils disposed therebetween to create an internal volume; and means within said internal volume.

[0017] In some cases, the device is used to drive current in multiple coils. In some cases, the device induces charge on superconducting coils. In some cases, the device includes a flux pump. In some cases, a magnetic field shield is included between the multiple coils and the internal volume. In some cases, a housing surrounds the multiple coils.

[0018] In another aspect, the invention can be broadly described as including a dipole magnet comprising an internal volume disposed within a toroidal superconductor configured to shield the internal volume from the magnetic field of the dipole magnet.

[0019] In some cases, a toroidal superconductor comprises multiple toroidal coils. In some cases, a device is included within an internal volume. In some cases, the internal volume is toroidal. In some cases, a toroidal superconductor has a circular and / or substantially circular and / or elliptical and / or substantially elliptical cross-section.

[0020] In another aspect, the invention may be broadly described as including a dipole field magnet comprising a plurality of toroidal superconducting coils configured to provide a magnetic field region between the toroidal superconducting coils that is lower than that outside the toroidal superconducting coils when current flows in the toroidal superconducting coils.

[0021] In another aspect, the invention may be broadly described as including a dipole field magnet comprising: an internal volume disposed within a superconducting coil, the superconducting coil being configured to provide a region of magnetic field within the internal volume that is lower than that outside the superconducting coil when current flows in the superconducting coil.

[0022] In another aspect, the invention may be broadly described as including a toroidal superconductor that surrounds an internal volume and is configured to shield the internal volume from a magnetic field.

[0023] In some cases, a toroidal superconductor comprises multiple toroidal coils. In some cases, a device is included within the internal volume. In some cases, the internal volume is toroidal. In some cases, the toroidal superconductor has a circular and / or substantially circular and / or elliptical and / or substantially elliptical cross-section. In some cases, the shielding of the internal volume depends on and / or is proportional to the current flowing in the superconductor coils. In some cases, the internal volume is toroidal.

[0024] In another aspect, the invention can be broadly described as including a suspended dipole reactor comprising: a dipole field magnet configured to be suspended, the dipole field magnet including an internal current driving device for driving within the superconducting dipole magnet. In some cases, the current driving device is surrounded by a plurality of toroidal superconducting coils.

[0025] In another aspect, the invention may be broadly described as including a dipole field magnet comprising a plurality of toroidal superconducting coils disposed about an internal volume and configured to provide a low magnetic field region in the internal volume relative to the outside of the dipole field magnet.

[0026] In some cases, the internal volume is formed between the inner diameter of the largest diameter superconducting coil and the outer diameter of the smaller diameter superconducting coil. In other cases, the internal volume is formed between the highest and lowest superconducting coils along the axial axis.

[0027] In another aspect, the invention may be broadly described as including a dipole field magnet comprising a plurality of toroidal superconducting coils configured to shield the internal volume between the coils from the magnetic field generated by the dipole field coils.

[0028] In another aspect, the invention can be broadly described as including a superconductor comprising: a plurality of toroidal superconducting coils arranged with respect to an internal volume, wherein the superconducting coils are configured to shield the internal volume from a magnetic field when current flows through the superconducting coils. In some cases, the coils are toroidal. In some cases, a current-driving device for driving current in the superconducting coils is included.

[0029] Features from one or more embodiments or configurations can be combined with features from one or more other embodiments or configurations. Additionally, more than one embodiment or configuration can be used together in a dipole field magnet or other systems that require or use a dipole field.

[0030] As used in this article, the term “(s)” following a noun refers to the plural and / or singular form of that noun.

[0031] As used herein, the term “and / or” means “and” or “or”, or where the context allows for both.

[0032] As used in this specification, the term "comprising" means "consisting of at least part of...". When interpreting the various statements in this specification that include the term "comprising", features other than those using the term or those beginning with it may also exist. Related terms such as "comprising" and "including" will be interpreted in the same manner.

[0033] References to the numerical ranges disclosed herein (e.g., 1 to 10) are also intended to be combined with references to all rational numbers within that range (e.g., 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9, and 10) and any ranges of rational numbers within that range (e.g., 2 to 8, 1.5 to 5.5, and 3.1 to 4.7), and thus all subranges of all ranges explicitly disclosed herein are explicitly disclosed herein. These are merely examples of specific intentions, and all possible combinations of numerical values ​​between the listed minimum and maximum values ​​should be considered as expressly stated in a similar manner in this application.

[0034] This disclosure may also be broadly interpreted to include any part, element, or feature that is individually or jointly mentioned or indicated in the description of this application, as well as any or all combinations of any two or more of the said parts, elements, or features.

[0035] Where reference is made herein to a known equivalent in the field to which this disclosure pertains, such known equivalent is considered to be incorporated herein as if described separately.

[0036] This disclosure includes the foregoing and also envisions its construction, of which only examples are given below. Attached Figure Description

[0037] Specific embodiments and modifications thereof will become apparent to those skilled in the art from the detailed description herein with reference to the following accompanying drawings, in which:

[0038] Figure 1 A prior art dipole field magnet is shown in cross-section.

[0039] Figure 2 A dipole magnet suspended in a vacuum container is shown in cross-section.

[0040] Figure 3 The magnetic field around the dipole magnet is shown.

[0041] Figure 4 The magnetic flux around the dipole magnet is shown.

[0042] Figure 5 A dipole field magnet with multiple coils is shown.

[0043] Figure 6 It shows Figure 5 The magnetic field surrounding a dipole magnet.

[0044] Figure 7 It shows Figure 6 The magnetic flux around a dipole magnet.

[0045] Figure 8 The diagram shows the structural support components. Figure 7A cross-sectional view of a dipole magnet.

[0046] Figure 9 It shows Figure 8 A dipole field magnet.

[0047] Figure 10 A dipole magnet in a housing is shown, with a reference axis shown.

[0048] Figure 11 It shows from Figure 8 A magnified view of the selected coil and coil windings in a dipole field magnet.

[0049] Figure 12 The magnetic field of the alternative dipole magnet is shown in cross-section.

[0050] Figure 13 The magnetic flux of the alternative dipole field magnet is shown in cross-section.

[0051] Figure 14 A plan view of a dipole field magnet with a device in a portion of the internal volume is shown in cross-section.

[0052] Figure 15 The internal volume of a dipole field magnet, including a single recess, is shown.

[0053] Figure 16 The internal volume of a dipole field magnet with multiple adjacent recesses is shown.

[0054] Figure 17 A dipole field magnet with multiple coils and an example shield is shown. Detailed Implementation

[0055] Figure 2 A dipole magnet 1 is shown suspended inside a vacuum container 26. A levitation device 21, such as a fixed coil including an electromagnet, may be arranged above the dipole magnet 1 to support it in place. The vacuum container 26 may be arranged on a support 25, such as a leg, to allow access from below. The vacuum container 26 may have an opening 27, such as an inlet, to allow the dipole magnet 1 to be inserted into and / or removed from the vacuum container 26. Although shown in the base of the vacuum container 26, it may alternatively be located on the side or top of the vacuum container 26. In some cases, the vacuum container 26 has at least one magnet support (not shown). The magnet support provides a resting position for the dipole magnet 1 when it is not suspended, preventing it from falling to the bottom of the vacuum container 26. This can be achieved by passing through a central opening in the magnet 1. (One or more) magnet supports may also restrict the upward and / or lateral movement of the dipole magnet 1.

[0056] The dipole magnet 1 includes a superconducting coil 50. The superconducting coil 50 is configured to carry a current when superconducting to create a dipole field, as indicated by magnetic flux lines 24 surrounding the dipole magnet 1. The superconducting coil 50 is oriented to extend radially about the central axis of the magnet 1. The dipole field 24 can be used to confine plasma, for example, for nuclear fusion. In a fully fusion reactor, additional devices can be used. For example: plasma source excitation devices, such as resonant microwave heating; and energy harvesting devices. The energy harvesting device can include a heat transfer system in or near the reactor chamber walls. The heat transfer system is configured to capture neutrons generated by the fusion reactor and convert their energy into heat, which can then be converted into power, for example, in a steam turbine. Additional coils or windings (not shown), such as Helmholtz windings, can be used to shape the magnetic flux lines 24.

[0057] Figure 3 The magnetic field 32 around the coil 30 inside the housing 31 of the dipole magnet 1 is shown. Figure 4 The magnetic flux lines are shown concentrated on coil 30 and extending radially outward. This view is shown in cross-section, where the origin 33 represents the center of the toroidal surface formed by the dipole magnet 1. During operation of the dipole magnet 1, a high magnetic field 32 is generated. This high field will affect all magnetically and / or magnetically sensitive objects in or near the dipole magnet 1, both inside and outside the housing 31. Figure 3 As shown, the magnetic field has a strength of at least 0.4 Tesla around the dipole magnet 1, but the specific strength will depend on the size and properties of the system.

[0058] High magnetic fields can have detrimental effects on devices located at or near a magnet. For example, an iron core will saturate in a high magnetic field, limiting the ability to use transformers. Similarly, any electronic device can be affected, particularly by dynamic fields, but even static fields will require heavy shielding, leading to flux losses in devices such as transformers and inductors, as well as trigger relays. While heavy shielding can prevent or mitigate some of the effects of high fields, the additional weight makes it difficult to use in many systems, such as levitated dipoles. Furthermore, the required amount of shielding may not scale well with increasing size.

[0059] Figure 5 A cross-section of an example dipole field magnet 1 using multiple coils 50 is shown. Although shown in cross-section, each coil 50 is annular (as the cross-section rotates about the origin 33). The use of multiple coils 50 allows for the formation of an internal volume 51 within the coils 50. The internal volume 51 may have physical boundary markings, such as a shield 52 optionally made of iron, or other housings. However, such a shield or housing is not required.

[0060] The arrangement of the toroidal superconducting coils 50 around the internal volume 51 can shield the internal volume 51 from at least one or both of the magnetic field generated by the superconducting coils 50 and the external magnetic field. By dividing the magnet into multiple toroidal superconducting coils 50 and spacing the coils 50 with respect to the internal volume 51, a low-field region is created within the magnet 1. This allows the device to be located within the low-field region formed in the internal volume 51, even in the presence of a significant external magnetic field. When current is present in the coils 50, the internal volume 51, which can be referred to as the low-field region, has a low magnetic field compared to the magnetic field outside the toroidal coils 50 or the magnet 1 itself. The low magnet magnetic field can be less than ten percent of the external field, less than one percent of the external field, or lower than the field strength required by the device within the magnet 1.

[0061] The number and arrangement of the loops in the superconducting coil 50 are variable. In some cases, electromagnetic simulations may be required to determine a suitable arrangement to provide adequate shielding for a sufficiently large internal volume 51. COMSOL Multiphysics, developed by COMSOL Corporation... TM This is an example of a suitable simulation procedure. In the simplest arrangement, two toroidal superconducting coils 50 can be used, arranged close enough together to create a small internal volume 51 directly between them, in which a low magnetic field shielded by the two coils 50 can be formed. However, adding additional toroidal coils 50 will improve the shielding relative to the external magnetic field and / or increase the size of the internal volume 51 that can be shielded.

[0062] In some cases, the dipole magnet 1 can be formed from a single ring or homogeneous superconductor structure shaped to provide the internal volume 51. For example, the interior of a monolithic or homogeneous superconductor ring can be hollowed out, or the superconductor ring can be fabricated to surround the internal volume 51. Alternatively, the single coil 50 can be helical to form a path around the magnet, such as tracking the periphery of the ring. In these cases, the internal volume 51 remains substantially surrounded by a superconductor, but the superconductor is not formed from multiple separable portions.

[0063] In this context, the use of "loop" or "ring" refers to the coil 50 forming a loop around the center 33 of the magnet 1. Although shown as substantially circular in the figures, the coil 50 can have different geometries and can be symmetrical or asymmetrical. When superconducting in the coil 50, forming a loop around the center 33 allows for the formation of a dipole field and allows for continuous current flow.

[0064] The selection and placement of coil 50 can be a trade-off between the amount of superconductor required and the mass or range of the shielded internal volume 51. The shielding effect can be considered analogous to protecting the internal volume 51 from a flexible sheet: the external magnetic field can be considered as an attempt to penetrate the flexible sheet into the internal volume 51. Coil 50 prevents the flexible sheet from penetrating. A continuous layer of superconductor around the internal volume would prevent any penetration of the flexible sheet. However, this would require a large amount of superconductor and be difficult to construct. For example, multiple adjacent toroidal superconductor coils 50 are possible, but this would increase the cost and weight of the superconductor used. Increasing the spacing between adjacent coils 50 and / or the placement of adjacent coils 50 reduces the amount of superconductor required. By carefully selecting the positioning of the coils 50, the spacing and / or placement can be configured to still protect the internal volume 51 from penetration by the flexible sheet. Similarly, due to the shielding provided by the coils 50, the arrangement of coils 50 around the internal volume 51 can be configured to provide a low-field region within the internal volume 51.

[0065] The current flowing in the toroidal superconducting coil 50 generates a magnetic field and shields the internal volume 51 from the external field. Magnetic fields obey the superposition principle, so opposing magnetic fields can cancel each other out. When current flows in multiple coils 50, each coil generates its own magnetic field. Due to the arrangement of the coils around the internal volume 51, the magnetic fields generated by the multiple coils 50 can superimpose on each other within the internal volume 51 to create a low-field region. This causes the coils 50 to shield the internal volume 51 from the magnetic field, resulting in a relatively low-field region. Since the shielding is caused by the current flowing in the coils, the shielding depends on and / or is proportional to the current. This means that a larger current can result in a larger shielding, allowing the system to scale effectively.

[0066] The current in the superconducting coil 50 may flow in the same direction in each or at least most of the coils 50. This direction is about the center 33 of the coil. However, in some cases, shimming coils or coils with current flowing in opposite directions may also be present, for example to help control the field or correct the uniformity in the magnetic field.

[0067] Multiple coils 50 are configured to shield the internal volume 51 from the magnetic field, but can shield a much larger amount of field compared to physical shielding such as iron, and can be significantly lighter. The amount of shielding achieved can depend on the amount of current flowing in the coils 50, meaning the shielding effect can scale with the size of the magnet 1.

[0068] The advantage of this system is that, because the internal volume 51 is shielded from the magnetic field 32, the internal volume 51 has a relatively low magnetic field relative to the outside of the magnet 1. This allows devices such as electronic devices, magnetically sensitive devices, and / or current-driven devices to be placed inside the internal volume 51 and operate without being affected by the potentially large magnetic field generated by the dipole magnet 1. This means that iron present within the magnet 1 (such as any transformer core) will be able to operate without saturation caused by the external magnetic field. This is particularly relevant to fusion reactors, as a high field strength is required when scaling up to fusion reactors.

[0069] In some cases, the means 130 for driving current in the superconducting coil 50 is located within the internal volume 51. The means 130 may be a current-driving device or a charging device, and may use induction to transfer power from a power source to the superconducting coil 50. A flux pump may have a first portion including an energy source inductively coupled to the superconducting portion. The superconducting portion is attached to or may be attached to the superconducting coil 50. The current-driving device may be a flux pump or a superconducting current-driving device configured to drive current into the superconducting coil 50. Alternative means 130, such as energy storage devices and / or control devices, may also be stored within the internal volume 51. Proximity of the means 130, or the current-driving device or pumping device, to the coil 50 allows for simple and efficient driving of current into the coil 50 and / or into the connection to the coil 50, while the current flowing through the coil 50 shields the internal volume 51 from the magnetic field, thereby reducing the magnetic field within the internal volume 51 relative to the magnetic field outside the superconducting coil 50. The device 130 for driving the current in the superconducting coil 50 allows for the use of a wider variety of superconductors. For example, HTS typically requires resistive junctions between coils or coil sections. An example is an HTS strip made of rare-earth elements (ReBCO). The presence of resistance causes a decrease in the current in coil 50. This may require maintaining or increasing the current. Driving additional current (one or more) in coil 50 by using, for example, a flux pump allows the current (and therefore the dipole field) to be maintained for a longer period. Advantageously, this system allows the current driver (such as a flux pump, etc.) to be stored in a low-field region on the magnet, thereby allowing for easier operation and / or reduced connection to the levitation magnet 1.

[0070] Figure 6 This shows the effect of current flowing through coil 50 around... Figure 5 The magnetic field of magnet 1 (shown by magnetic field level 32). Figure 7 The corresponding magnetic flux is shown (indicated by flux line 40). Figure 6 and Figure 7An internal volume 51, essentially devoid of a magnetic field, has been created within the toroidal coil 50. The internal volume 51 can be considered as forming a ring at the center of the coil 50 (between the smallest and largest diameter coils). This internal volume 51 extends in a toroidal or toroidal path around the center 33 of the magnet 1. Figure 6 The inner periphery 61 and outer periphery 62 of magnet 1 are shown.

[0071] The specific shape of the internal volume 51 will depend on the arrangement of the ring coil 50. Figure 6 and Figure 7 In the example, fourteen coils 50 are used; however, the number of coils 50 can vary, for example, depending on the required size and shielding within the internal volume 51. There can be at least four coils 50, at least six coils 50, at least eight coils 50, or at least ten coils 50. A larger volume or number of coils 50 can be arranged toward the inner periphery 61 of the magnet 1 compared to the outer periphery 62 of the magnet, because the inner periphery is where most of the current will flow in the coils 50 due to its toroidal shape. The toroidal shape of the superconducting coils 50 means that a greater current density will appear in the internal portions of each coil 50 and throughout the inner periphery 61 of the magnet 1. By increasing the volume of the superconductor in the inner coils 50 (or the inner periphery 61 of the magnet), a larger current can be supported, and the magnetic shielding of the internal volume 51 is improved. In some cases, the magnet 1 may include at least one coil arranged in segments of thirty degrees, twenty degrees, or ten degrees. In some cases, wider gaps may exist in at least one segment of the magnet, causing the coils 50 to form a 'C' shape in cross-section rather than a circle or ellipse.

[0072] Figure 6 and Figure 7 This diagram illustrates a high-density coil 50 within the inner periphery 61 of the magnet 1, followed by spaced-apart coils 50 around the outer periphery 62 of the magnet 1. The size and / or spacing of the coils 50 can depend on the desired shielding, with larger spacing between the coils 50 reducing shielding. Spaced-apart the coils 50 from each other, this reduces the amount of superconductor required to form the magnet 1 and allows for control over the shape of the internal volume 51. This spacing creates gaps in the axial and / or radial directions. The spacing can be a trade-off between reducing the amount of superconductor required and ensuring adequate shielding of the internal volume 51.

[0073] Figure 8 It shows Figure 6 and Figure 7A cross-sectional view of a 3D model of magnet 1 is shown. The internal volume 51 is shown with an additional shield 52 to reduce any residual magnetic field. Shield 52 may be made of ferromagnetic material, ferromagnetic material, or other material configured to reduce the magnetic field. The shape of shield 52 may conform to the shape of one or more devices within the internal volume 51. In other cases, shield 52 may be replaced by a housing for one or more devices 80 within the internal volume 51.

[0074] Figure 17 An alternative example of shielding 50 is shown. Again, coil 50 substantially surrounds shielding 52. One or more devices are protected within an internal volume 51, which may be at least partially or completely defined by shielding 50. The internal volume may be located within shielding 50. Shielding is shown with variable thickness. The thickness can be varied to have greater flux reduction in areas with a stronger magnetic field during use of magnet 1. However, since the saturation field strength of shielding 52 is independent of thickness, the shielding material must be selected to have a sufficient saturation level. Figure 17 A thicker region 522 at the top of shield 52 is shown. A thicker region 521 on the inner circumference of shield 52 is also shown. The thicker regions can be positioned in other ways depending on the high flux region. The thicker region 521 is shown as a connection between two shields. However, the shields can be substantially continuous, or the blocks can be connected at different locations. For example, the location can be selected to facilitate assembly.

[0075] In some cases, shielding 52 can provide significant field reduction. For example, coil 50 may be reduced in size or repositioned, leaving a larger field in the internal region 51 than desired. However, shielding 52 can be used to attenuate this larger field to a suitable level. Shielding 52 will need to be thick enough to reduce the magnetic flux level within shielding 52 over operating cycles. In some cases, this example can balance the weight of shielding 52 with the complexity or amount of superconductor required in coil 50. In such examples, a low-field region can be provided by a combination of coil 50 and shielding 52. In some cases, a thicker (or more absorbent, or more absorbent material) shielding 52 can balance a smaller coil 50. To provide shielding effectiveness, the material of shielding 52 is chosen to have a saturation point above the expected maximum field of the internal volume 51.

[0076] Furthermore, the use of shielding 52 also maintains the field shape during the charging of some of the coils 50. Specifically, the coils 50 are non-insulated. Non-insulated coils do not have insulation between layers or between individual superconductor layers. Non-insulated coils 50 allow radial current to pass through the turns of the windings in the coil 50. This additional conduction path allows the coil 50 to withstand error current superimposed on the operating current of the magnet 1. Error current can be absorbed due to the additional current path between the turns of the windings and along the windings. The operating current of the magnet is parallel to the windings of the individual coils 50 and is independent of the current present in the other coils. Error current can be induced, for example, by changing the field conditions during the charging of the magnet 1. Error current in the coil 50 can cause the coil 50 to operate far beyond its design specifications, which in turn may increase the field strength in low-field regions. Therefore, there is a possibility of damaging the device 130 within the internal volume 51 or affecting the performance of the device 130 during these transient periods (such as during charging).

[0077] The presence of a shield 52 made of a ferromagnetic material (such as iron, which saturates at about 1-2 Tesla) or at least a field-absorbing medium within or about the inner region 51 can reduce these error currents. This is because the shield 52 redirects a portion of the field generated by the coil, thereby reducing the coupling (mutual inductance) between the coils on opposite sides of the magnet. Reduced mutual coupling means a smaller error current in the coil, and therefore a smaller total field in the inner volume 51. Alternatively, an insulated coil 50 can be used. However, the insulated coil 50 is mechanically less stable and less resilient to superconducting 'quench' events. Mechanical stability may be reduced because the filling medium (typically wax or epoxy) is generally weaker than other coil materials. In some cases, the shield 52 may be located at least between corresponding coils arranged symmetrically on opposite sides of a radial plane, such as... Figure 5 As shown. Although in Figure 5 and Figure 17 The diagram shows a continuous shield 52, but in some cases, the shield includes one or more openings. In some cases, the shield 52 may be arranged to be thicker near the location of the coil 50 to better mitigate the field from the coil 50.

[0078] Specifically, due to the forces exerted by the magnets during operation, supports 81, 82, and 84 are used to position and secure the coils 50 in place. In this case, the supports include a metal section 81 (which may include steel) for strength and an insulating section 82 for controlling temperature or heat flow. The insulating section 82 may include glass fiber, such as G10. Conductive interconnects 84, which may include copper, are also present to connect the coils 50. Figure 8These layers 81, 82, and 84 are shown to be connected, for example, by using fasteners such as bolts 83. The supports 81, 82, and 84 should be designed to withstand the expected forces on the coil 50 during operation. These may include forces pushing out from the center of the magnet, as well as forces pushing vertically to compress the coil 50 together. A superconducting current pump 80 is shown within the internal volume 51. Other devices 130 may also be located within the internal volume 51, or alternatively. Devices may extend around the entire internal volume 51, but typically they will only occupy a portion of the internal volume 51. Additional devices 130 or equipment may be placed in the remaining internal volume 51.

[0079] Figure 9 Magnet 1 is shown. The current pump 80 is visible in a section of the toroidal magnet 1. Although shown as a ring, magnet 1 can have alternative shapes. For example, coil 50 can be oval, elliptical, more preferably square, or substantially square, depending on the application of magnet 1. In some cases, magnet 1 has a variable diameter: where the diameter extends to create a large internal volume 51 to accommodate (one or more) devices, and then decreases in other sections where the devices are not needed. The diameter reduction can be a reduction in the diameter of the inner perimeter 61, the outer perimeter 62, or both.

[0080] Figure 10 The diagram shows that, in use, the magnet can be arranged within a housing 31 surrounding the magnet 1. The housing can be used to contain coolant within the magnet 1 and / or to prevent damage to the magnet 1. Figure 9 The reference axis of magnet 1 is also shown, wherein the axial or height axis z passes through the center of the magnet, the radial axis R extends horizontally away from the central axis, and the azimuth or angular axis φ.

[0081] Figure 11 It shows Figure 6 and Figure 7 The image shows an enlarged cross-section of the coil 50 on the inner side of the magnet 1. The coils 50 can be formed by any suitable method. In this example, they are formed from superconducting turns 110, each turn comprising at least one layer 114 of a superconducting (e.g., HTS) strip wound to form a ring-shaped coil 50. Spacer layers 111, for example made of a metal such as brass or stainless steel, can be arranged between adjacent superconducting layers 114 to control the characteristics of the coils 50. In this example, the two innermost coils 50 have a larger spacer layer thickness than the remaining coils 50; however, this is not necessary. The use of strips can allow the coils 50 to have substantially the same height, such as... Figure 11As shown. The coil may have a boundary or housing 117. The housing 117 may be conductive, for example, made of copper. The housing 117 may electrically connect the individual turns 110 and / or layers 114 of the coil. A support layer 115 may separate adjacent layers of the superconducting strip to provide mechanical stability to the coil 50. The support layer 115 may be made of epoxy resin, other electrically insulating materials, solder, or other conductive materials. Compared to, for example, epoxy resin, using a conductive material such as solder for the support layer 115 reduces the inter-turn contact resistance of the coil and / or provides an optional current path around a damaged superconductor (if present).

[0082] Other arrangements for forming the coil are possible, including: "dry winding," where no material is present between layers 114 and adjacent superconducting layers 114 (optionally coated) are in direct contact; "metal insulation," where metal strips are co-wound between superconducting layers 114; and conductive epoxy resin. The superconducting strip may include a superconducting material (e.g., YBCO) sandwiched between multiple layers. The multiple layers may include copper on both sides of the strip. The insulated coil 50 will have one or more insulating layers added between the individual superconducting layers 114 or between the individual turns 110 of the superconducting layers. The insulating layers may include, for example, wax or epoxy resin. Other superconducting strip arrangements or structures may also be used.

[0083] In some cases, the lengths of the individual coils 50 are configured to shape and / or size the internal volume 51. Alternatively, strips and / or coils 50 of varying heights can be used. The coil height can be chosen based on the strip height (e.g., 12 mm). However, in other cases, the heights of the individual coils can be configured to shape and / or size the internal volume 51. Alternative materials (e.g., superconducting strips, wires, or other superconducting materials) can be used to form the coils 50. The turns 110 and / or layers 114 of the coil are shown as having a constant orientation or angle. The orientations shown indicate that the individual layers are arranged radially. In some cases, the coils 50 can be bent or shaped, causing variations in the orientation of the turns 110 and / or layers 114. This can be used to shape the internal volume 51. In these examples, the use of strips results in coils 50 with a substantially rectangular cross-section; however, coils 50 of different shapes, such as elliptical or circular, can be used.

[0084] Figure 12 The magnetic field 32 of an alternative example magnet 1 using a toroidal coil 50 is shown. Figure 13The flux lines 40 of the same alternative magnet 1 are shown. In this case, a half-cross section is shown, with the lower half being a mirror image. This example uses ten coils 50 per half (20 coils in total) to produce a greater amount of shielding, but also uses more superconductors than in the previous example. Similar to the previous example, there is a greater amount of superconductor towards the inner periphery of magnet 2. At least some of the superconducting coils 50 overlap. That is, the inner radius of the coil is smaller than the outer radius of the adjacent coil. For example, coils 501 and 502 overlap because the inner radius of coil 501 is smaller than (i.e., closer to the center 33) the outer radius of coil 502. In some cases, the overlap may also or alternatively be along the z-axis (i.e., vertically). In some cases, additional superconducting coils 50 may be added to the magnet, with each superconducting coil 50 filling the space. Figure 12 and Figure 13 One of the remaining gaps, to further surround the internal volume 51 and / or provide additional shielding. As Figure 8 As shown, at least some of the coils 50 may be adjacent to or substantially adjacent to each other, thereby forming a layered or sandwich configuration. The coils 50 may be separated by a distance less than their height. The separation distance may be less than one-quarter or one-half of their height. The magnet 1 may include a plurality of spaced-apart coils 50 and a plurality of substantially adjacent coils 50.

[0085] Figure 6 , Figure 7 and Figure 12 and Figure 13 A cross-section of a uniform loop coil 50 with a circular inner and outer perimeter is shown. However, the loop coil 50 is not limited to this shape. In some cases, the coil 50 may be oval or elliptical. The loop coil 50 may be more square or substantially square. The ability to change the shape of the coil 50 will depend on the use of the magnet 1 (where symmetry and balance are required, the shown loop version may be advantageous). Similarly, the coil 50 may not be vertically symmetrical; the coils 50 in the upper half of the magnet 1 may, for example, differ in number or arrangement from those in the lower half of the magnet 1. In some cases, the magnet 1 is toroidal or toroidal in shape.

[0086] Using different coils 50 may make the magnet 1 not substantially toroidal. That is, the circumference of the torus may not be circular and / or the cross-section of the main body of the torus may vary radially. In the context of this discussion of toruses, it should be understood as referring to the broad concept of a ring-shaped object, such as a tube extending around a central axis. The tube is hollow or partially hollow to form an internal volume 51. The internal volume 51 formed by the multiple coils 50 should also be understood as being centered relative to the multiple coils 50, and therefore within a toroidal structure. It is vertically surrounded by the highest and lowest coils 50 on the axial axis (z) and horizontally surrounded by the smallest and largest radius coils 50, or further separated on the radial axis (R).

[0087] Figure 14 The outline of the internal volume 51 of magnet 1 is shown as an annular ring or toroidal volume with a cross-section. Figure 14 This is a plan view looking down from above the magnet 1, showing only the internal volume 51. The inner radius 134 and outer radius 135, measured from the center 33 of the magnet 1, are shown. Devices 130, such as a current-driven device 80, are arranged within this internal volume 51. In some cases, they extend throughout the entire internal volume 51. However, as... Figure 13 As shown, multiple devices 80 and 130 can exist, each arranged separately in the internal volume 51. For example, devices such as batteries, current-driven devices, and control devices can be located within the internal volume 51.

[0088] Figure 15 An alternative arrangement is shown in which the diameter of the internal volume 51 is variable about the circumference of the magnet 1. Figure 15 This is a plan view of the center 33 viewed from above the magnet 1. In this case, a relatively wide recess 151 exists within the internal volume 51, which is configured to accommodate a device in which the internal volume 51 of the remaining circumference of the magnet 1 is reduced and / or variable. In some cases, the internal volume 51 may disappear for a portion of the circumference (i.e., have zero width). For example, this can reduce the desired size of the magnet 1 and / or the amount of superconductivity used.

[0089] Figure 16 An alternative arrangement of multiple recesses 151 around the circumference of magnet 1 is shown. Figure 16 This is a plan view looking down from above magnet 1. Recesses 151 are shown as connected to each other, but they may be spaced apart. In some cases, each recess 151 may accommodate one or more devices. The use of a variable-diameter coil 50 allows the shape of the internal volume 51 to vary with respect to the radius of magnet 1. In some cases, only the inner radius 134 or the outer radius 135 of the internal volume 51 may be changed, or both the radius and / or diameter may be changed.

[0090] The examples in this article use a toroidal coil 50 aligned or centered on the same axis to achieve coaxiality. The common axis is the z-axis of the toroidal magnet 1 (e.g., Figure 9 (As shown). Variations in the radius of the loop coil 50 and / or the spacing of the loop coils 50 along the z-axis allow for the formation of an internal volume 51 between the loop coils 50. In some cases, the loop coils 50 may be offset relative to the axis, for example, to create a variable-sized internal volume 51 for manufacturing reasons, or to provide different field shapes.

[0091] These examples illustrate the use of multiple independent loop coils 50. However, a single coil having multiple loops about the magnet 1 can also be used to form an internal volume between the individual coils. For example, the ends of the individual loop coils 50 can be connected to adjacent coils 50 to form a single winding. Alternatively, the individual coils can be spirally wound about the surface of the internal volume 51. In some cases, at least some of the multiple coils 50 have the same or substantially the same characteristics. This can simplify modifications or repairs to the magnet 1, as a known set of coils 50 can be used for replacement.

[0092] The example illustrates a superconducting coil 50 with a constant height and horizontal alignment. Variations in the superconducting properties of the coil 50 can be achieved by modifying the type of superconductor, the spacing between turns 110 and / or layers 114, and / or the length of the coil 50. This allows for simpler design and manufacture of the magnet. In some cases, the coil 50 can have other varying characteristics to control performance. For example, the angle of at least one or all of the coils can be configured to shape the internal volume 51. For example, consider… Figure 7 The coil 50, the coil cross-section (i.e., Figure 5 The angle of the cross-section (visible in the image) can be configured to be substantially parallel and / or perpendicular to the flux lines. In some cases, the cross-section angle can be adjusted to reduce the spacing between adjacent coils 50. The height of the superconducting coil 50 can also be adjusted, for example, by using different superconducting strip widths. The position of the coil 50 within the container 26 can also be adjusted, for example, to minimize the size of the container 26 and / or balance the magnet.

[0093] The examples described in this paper have already used superconductors as high-temperature superconductors. However, this technique can be applied to other superconductors. High-temperature superconductors can refer to superconductors that can reach a superconducting state at temperatures above 30 K, or superconductors that can be superconducting when cooled only by liquid nitrogen. Low-temperature superconductors typically require temperatures below 30 K to become superconducting, thus requiring liquid helium for cooling.

[0094] Magnetic flux pump

[0095] The device within internal volume 51 can be a superconducting current pump, also known as a flux pump. The current pump is configured to provide a stable high current source to drive current into a superconducting circuit (such as a toroidal coil 50). Different types of current pumps are known, including generator flux pumps and rectifier flux pumps. An example of a generator flux pump is shown, for example, by reference to WO2016024214A1, which is incorporated herein by reference. An example of a rectifier flux pump is shown, for example, by reference to WO2022164330A1, which is incorporated herein by reference. These current pumps have an iron core or yoke that saturates in a high magnetic field. Connecting a current pump across a superconducting load will allow an increase in the increment of flux in the loop, thereby increasing the current in the superconductor. In a simplified circuit model of a rectifier flux pump, a high current source (typically provided by the output of a step-down transformer) is connected in parallel with a switch to the superconducting load. An AC current is induced in the circuit loop between the high current source and the switch, and then rectified into a DC voltage in the loop between the switch and the superconducting load. The switching and / or rectifier section may be more complex, involving multiple switches or other rectification techniques; however, the general operating mode is the same. A transformer is used to transfer power from the power source to the superconducting section of the current pump, and a rectifier is used in the superconducting section to create the DC current to be fed into coil 50.

[0096] Alternative technologies and devices can be used to charge the superconducting coil 50 and / or disposed within the internal volume 51 surrounded by the superconducting coil 50. A flux pump provides a lightweight, relatively small current-driven device compatible with the internal volume 51 within the toroidal coil 50 and capable of levitation within the magnet 1. An alternative current-driven device 80 can be used.

[0097] Dipole field magnet 1 has already been discussed in relation to fusion reactors. However, magnet 1 can be applied to alternative applications. For example, it can be used to provide an improved magnetic torque converter for the movement of objects in space. A dipole field magnet arranged on a gyroscope aligns its magnetic field with the Earth's magnetic field. The ability to store, for example, a current pump or current-driven device within the magnet avoids the need for external contact, thus improving the ability to align the dipole field magnet. By aligning with the Earth's magnetic field, the dipole magnet allows surrounding devices to more accurately measure and / or use the magnetic field for directional control, because the dipole magnet can be configured to generate a magnetic field significantly stronger than the Earth's. For example, a series of solenoids arranged around the magnet can interact with the magnet (which follows the Earth's magnetic field). In this way, the magnet provides an improved local representation of the Earth's magnetic field without requiring direct use of the Earth's magnetic field. Further applications of shielding devices in dipole field magnets can also utilize this technology.

[0098] While certain embodiments and examples are disclosed herein, the subject matter of the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses, as well as modifications and equivalents thereof. Therefore, the scope of the appended claims or embodiments is not limited to any particular embodiment described herein. For example, in any method or process disclosed herein, the actions or operations of the method or process may be performed in any suitable order and are not necessarily limited to any particular disclosed order. Various operations may be described sequentially as multiple discrete operations in a manner conducive to understanding certain embodiments; however, the order of description should not be construed as implying that these operations are sequentially related. Additionally, some structures described herein may be embodied as integrated components or separate components. For the purpose of comparing various embodiments, certain aspects and advantages of these embodiments are described. Not all of these aspects or advantages must be achieved by any particular embodiment. Thus, for example, various embodiments may be performed in a manner that achieves or optimizes one or a set of advantages as taught herein, without necessarily achieving other aspects or advantages as may also be taught or suggested herein.

[0099] It should be emphasized that many variations and modifications can be made to the embodiments described herein, and elements of these embodiments should be understood as existing in other acceptable examples. All such modifications and variations are intended to be included within the scope of this disclosure and protected by the appended claims. Furthermore, nothing in the foregoing disclosure is intended to imply that any particular component, feature, or processing step is necessary or required.

Claims

1. A dipole field magnet, comprising: Multiple toroidal superconducting coils are configured to shield the internal volume between the toroidal superconducting coils from the magnetic field of the dipole magnet.

2. The dipole field magnet according to claim 1, wherein, The internal volume is annular.

3. The dipole field magnet according to any one of the preceding claims, wherein, The internal volume is toroidal.

4. The dipole field magnet according to any one of the preceding claims, wherein, The superconductor coil is coaxial.

5. The dipole field magnet according to any one of the preceding claims, wherein, The superconductor coils are axially spaced.

6. The dipole field magnet according to any one of the preceding claims, wherein, At least two of the coils have the same cross-sectional dimensions.

7. The dipole field magnet according to any one of the preceding claims, wherein, The plurality of coils are symmetrical above and below the radial plane.

8. The dipole field magnet according to any one of the preceding claims, wherein, A coil with a larger volume is positioned towards the inner periphery of the magnet, compared to the outer periphery of the magnet.

9. The dipole field magnet according to any one of the preceding claims, wherein, The plurality of coils includes at least four coils.

10. The dipole field magnet according to any one of the preceding claims, wherein, The magnetic field of the dipole magnet is generated by the current flowing in the toroidal superconducting coil.

11. The dipole field magnet according to any one of the preceding claims, wherein, The plurality of coils form one or more of a circular, substantially circular, elliptical, or substantially elliptical cross-section.

12. The dipole field magnet according to any one of the preceding claims, wherein, At least two of the plurality of coils are spaced apart.

13. The dipole field magnet according to any one of the preceding claims, wherein, Each of the plurality of coils comprises multiple turns and / or layers of a superconductor.

14. The dipole field magnet according to claim 14, wherein, The individual turns and / or layers of the plurality of turns and / or layers are arranged in the same orientation.

15. The dipole field magnet according to any one of the preceding claims, wherein, The superconductor includes at least one of a superconducting strip and a superconducting wire.

16. The dipole field magnet according to any one of claims 1 to 18, comprising means disposed within the internal volume.

17. The dipole field magnet according to claim 19, wherein, The device is a means for driving the current in the plurality of coils.

18. The dipole field magnet according to claim 20, wherein, The device induces charge on the superconducting coil.

19. The dipole field magnet according to any one of the preceding claims, comprising a magnetic field shield between the plurality of coils and the internal volume.

20. The dipole field magnet according to claim 19, wherein, The magnetic field shield is configured to reduce inductive coupling between coils on each side of the magnetic field shield.

21. The dipole field magnet according to any one of claims 19 and 20, wherein, The magnetic field shield has a variable thickness, which is optionally configured to be thicker in high-field regions during use.

22. The dipole field magnet according to any one of the preceding claims, comprising a housing surrounding the plurality of coils.

23. A reactor chamber comprising a dipole field magnet according to claims 1 to 22.

24. The reactor chamber according to claim 23, comprising: Vacuum container; as well as A levitation device for levitizing the dipole magnet.

25. A dipole field magnet, comprising: Multiple toroidal superconducting coils are configured to create an internal volume between the multiple toroidal superconducting coils; And the devices within the internal volume.

26. A suspended dipole reactor, comprising: A dipole magnet, configured to levitate. The dipole field magnet includes an internal current driving device for driving the superconducting dipole magnet.

27. A dipole field magnet comprising a plurality of toroidal superconducting coils configured to shield the internal volume between the coils from the magnetic field generated by the dipole field coils.

Images