Superconducting thermal switch and space extremely low temperature system

Abstract

The invention relates to the technical field of ultra-low-temperature refrigeration, in particular to a superconducting thermal switch and a space ultra-low-temperature system.The superconducting thermal switch comprises a superconductor in a thin foil shape, connecting structures are arranged at the two ends of the superconductor respectively, the connecting structure at one end is used for being connected with a salt pill, and the connecting structure at the other end is used for being connected with a radiator; the coil is arranged around the circumferential direction of the superconductor, a magnetic field in the axial direction is formed in the center of the coil when the coil is electrified, and at least one part of the superconductor is perpendicular to the axial direction, so that the heat flow direction of the part of the superconductor is perpendicular to the magnetic field direction. According to the scheme, the defect that a traditional thermal switch is not ideal in use effect in an extremely low temperature environment in the prior art is overcome, and stable and efficient thermal connection and disconnection control in the extremely low temperature environment is achieved.

Description

Technical Field

[0001] The present invention relates to the field of ultra-low temperature refrigeration technology, and in particular to a superconducting thermal switch and a space ultra-low temperature system. Background Art

[0002] In the field of ultra-low temperature refrigeration technology, especially for applications requiring temperatures below 1 K, several technologies, including adsorption refrigeration, dilution refrigeration, and adiabatic demagnetization refrigeration, are widely used. In modern space probes, such as superconducting edge converters and X-ray microcalorimeters, operating temperatures are required to be as low as 100 mK or below. Adsorption refrigeration can only achieve a minimum temperature of 260 mK, which cannot meet the needs of such probes. Dilution refrigeration and adiabatic demagnetization refrigeration can achieve a minimum temperature of around 2 mK. However, since conventional dilution refrigerators rely on gravity to operate, this limits their effectiveness in space applications. In contrast, adiabatic demagnetization refrigerators have become a key refrigeration method for achieving temperatures below 100 mK in space environments because they are not affected by the microgravity environment.

[0003] The core of an adiabatic demagnetization refrigerator's operation lies in the performance of its internal thermal switch, which directly impacts overall system efficiency. This process involves the effective removal of the magnetization heat generated by the salt pellets during magnetization and the precise control of the adiabatic state of the salt pellets during the subsequent removal of the magnetic field to produce a cooling effect. Traditional thermal switches include mechanical, air-gap, and magnetoresistive types, but each has its own shortcomings. Mechanical thermal switches are unsuitable for space applications due to their complex internal structure and the risk of damage from frequent operation. Air-gap thermal switches only operate effectively above 200 mK. Magnetoresistive thermal switches require a large magnetic field to maintain their open state, potentially interfering with other components within the cryogenic system. Consequently, traditional thermal switch solutions have been less than ideal for use in ultra-low temperature refrigeration. Summary of the Invention

[0004] The present invention provides a superconducting thermal switch and a space cryogenic system, which are used to solve the defect of conventional thermal switches in the prior art that the performance is not ideal in cryogenic environments, and to achieve stable and efficient thermal connection and disconnection control in cryogenic environments.

[0005] The present invention provides a superconducting thermal switch, comprising: a superconductor in the form of a thin foil, with connection structures provided at both ends of the superconductor, wherein the connection structure at one end is used to connect to a salt pill, and the connection structure at the other end is used to connect to a radiator; a coil arranged in a circumferential direction around the superconductor, wherein when the coil is energized, an axial magnetic field is formed at the center of the coil, and at least a portion of the superconductor is perpendicular to the axial direction, so that the heat flow direction of this portion of the superconductor is perpendicular to the direction of the magnetic field.

[0006] According to one embodiment of the present invention, the connection structure includes copper joints, and the copper joints at both ends of the superconductor are detachably connected to the salt pill and the radiator, respectively.

[0007] According to one embodiment of the present invention, the copper joint is connected to the end of the superconductor by welding.

[0008] According to one embodiment of the present invention, the coil is a solenoid coil or a Helmholtz coil wound by a superconducting wire.

[0009] According to one embodiment of the present invention, the thickness of the thin foil-shaped superconductor is less than or equal to 0.1 mm.

[0010] According to one embodiment of the present invention, the superconductor is arranged in a zigzag or serpentine shape within the coil.

[0011] According to one embodiment of the present invention, the superconductor includes a plurality of parallel portions perpendicular to the axial direction and turning portions connecting adjacent parallel portions; the total length of the parallel portions is greater than the total length of the turning portions.

[0012] According to one embodiment of the present invention, a magnetic shielding layer is provided on the outer side of the coil.

[0013] According to one embodiment of the present invention, the magnetic shielding layer covers at least the outer circumferential surface of the coil and both ends of the coil in the axial direction.

[0014] The present invention also provides a space ultra-low temperature system, comprising: a radiator; an adiabatic demagnetization refrigerator provided with salt pills; and the superconducting thermal switch of the above embodiment, wherein the superconducting thermal switch is arranged between the salt pills and the radiator.

[0015] The superconducting thermal switch and space ultra-low temperature system provided by the present invention adopt a thin foil-shaped superconductor as the core heat transfer element, and set connection structures at both ends thereof to connect the salt pill and the radiator respectively. Combined with the axial magnetic field generated by the coils arranged in the circumferential direction of the superconductor, at least a portion of the superconductor is perpendicular to the direction of the magnetic field. This design makes the heat flow direction of this part of the superconductor perpendicular to the direction of the magnetic field. Under the action of the magnetic field, it can effectively control its transition from the superconducting state to the normal state, thereby significantly changing its thermal conductivity and realizing the ON / OFF state switching of the thermal switch. This structure not only has the advantages of long life and high reliability, but also avoids the problem of mechanical wear; at the same time, it can utilize superconducting materials with a lower critical magnetic field to work stably at extremely low temperatures, and will not generate strong magnetic interference to the salt pill or other low-temperature components. It is particularly suitable for adiabatic demagnetization refrigeration systems in ultra-low temperature environments in space, and meets the needs of modern space ultra-low temperature systems for high-performance thermal switches. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a structural schematic diagram of the superconducting thermal switch provided by the present invention.

[0018] Figure 2 The figure is a schematic structural diagram of the superconductor of the superconducting thermal switch provided by the present invention.

[0019] Reference numerals: 10. Superconductor; 11. Copper joint; 12. Parallel portion; 13. Turning portion; 20. Coil; 21. Magnetic shielding layer. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0021] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. It should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "set", "install" and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0022] The following combination Figure 1-Figure 2 Specific embodiments of the superconducting thermal switch of the present invention are described.

[0023] like Figure 1 As shown, the present invention provides a superconducting thermal switch, comprising: a superconductor 10 in the form of a thin foil, wherein the thin foil means that the superconductor 10 is processed into a very thin sheet or foil form, and a connection structure is provided at both ends of the superconductor 10, wherein the connection structure at one end is used to connect to a salt pill, and the connection structure at the other end is used to connect to a radiator; a coil 20, which is arranged in the circumferential direction of the superconductor 10, and when the coil 20 is energized, an axial magnetic field is formed at the center position of the coil 20, and at least a portion of the superconductor 10 is perpendicular to the axial direction, so that the heat flow direction of this portion of the superconductor 10 is perpendicular to the magnetic field direction. Specifically, the superconducting thermal switch realizes the thermal switching function based on the difference in thermal conductivity of the superconducting material in different states. When the superconductor 10 is in a superconducting state (that is, the temperature is lower than its critical temperature T c And the external magnetic field is less than its critical magnetic field H c ), electrons form Cooper pairs and no longer participate in heat conduction. At this time, phonons become the main heat conduction mechanism, resulting in a significant decrease in thermal conductivity. When the coil 20 is energized to generate a sufficiently strong magnetic field, the superconductor 10 is partially or entirely in a normal state (i.e., the magnetic field exceeds H c ), electrons re-participate in heat conduction, and the thermal conductivity rises rapidly, thereby achieving a high thermal conductivity state in the "ON" state. By controlling the on and off of the current in the coil 20, the thermal conductivity state of the superconductor 10 can be regulated, thereby realizing the opening and closing of the heat flow. The superconducting thermal switch according to this embodiment has a long life and high reliability compared to a mechanical thermal switch, avoiding the problem of mechanical wear caused by frequent operation; compared with an air gap thermal switch, the lower limit operating temperature is lower, and it can operate stably at 100 mK or even below a few millikelvin; compared with a magnetoresistive thermal switch, the magnetic field required to maintain the OFF state is smaller, so the magnetic interference is extremely low and will not affect other sensitive devices in the low-temperature system; at the same time, compared with the same type of thermal switch, the present invention can effectively avoid the problem of high thermal conductivity of the superconducting thermal switch in the OFF state caused by the magnetic flux freezing phenomenon by optimizing the direction of magnetic field application and the structural design of the superconductor 10, further improving the thermal isolation performance of the thermal switch.

[0024] In use, this superconducting thermal switch is used in adiabatic demagnetization refrigerators within space cryogenic refrigeration systems. During the magnetization phase, the salt pellet generates heat due to magnetization. At this time, coil 20 is energized, normalizing the superconductor 10 and maintaining high thermal conductivity. This ensures that the magnetization heat generated by the salt pellet is efficiently conducted through the superconductor 10 to the heat sink and dissipated. Once the salt pellet cools to the target temperature, the current in coil 20 is disconnected, causing the superconductor 10 to return to its superconducting state. This causes a sharp drop in thermal conductivity, resulting in thermal isolation and a thermally isolated state between the salt pellet and the heat sink. The magnetic field is then gradually removed, allowing the salt pellet to cool, achieving a cooling effect. This process can be repeated periodically to meet intermittent cooling requirements. Because this thermal switch has no moving parts, it offers long life and high reliability. Furthermore, the required critical magnetic field is low, preventing significant magnetic interference with the salt pellet or other cryogenic components, making it particularly suitable for space applications in microgravity environments.

[0025] Furthermore, the superconductor 10 of the superconducting thermal switch is preferably made of type I superconducting material, such as thin metal foils of lead (Pb), tin (Sn), or indium (In). These materials exhibit a low critical magnetic field and excellent processing properties, enabling stable operation at extremely low temperatures ranging from a few millikelvin to hundreds of millikelvin. The coil 20 can be made of either high-temperature superconducting windings or conventional copper windings, depending on the actual operating temperature and power consumption requirements. The connection structure can be designed using welding, crimping, or flexible wires to accommodate varying installation conditions and the effects of thermal contraction. Furthermore, a temperature sensor and feedback control system can be integrated to enable real-time monitoring of the thermal switch status and automatic switching control, enhancing the system's intelligence and operational stability.

[0026] According to the present invention, a superconducting thermal switch comprises a connection structure comprising copper joints 11. The copper joints 11 at each end of a superconductor 10 are removably connected to a salt pill and a heat sink, respectively. These copper joints 11 serve as transitional interfaces for heat conduction, ensuring good thermal contact between the superconductor 10, the salt pill, and the heat sink. They are also removable for easy installation, replacement, and maintenance. The connection between the copper joints 11 and the superconductor 10 is preferably a low-thermal-resistance, highly stable welding method, capable of maintaining structural integrity and heat conduction efficiency in extremely low-temperature environments, thereby ensuring reliable operation of the thermal switch under extreme operating conditions.

[0027] Furthermore, according to a superconducting thermal switch of the present invention, the copper joint 11 is connected to the end of the superconductor 10 by welding. The welding temperature and solder selection can be determined based on the physical properties of the superconducting material of the selected superconductor 10. When the superconductor 10 is made of a type I superconducting material with a low melting point, such as lead (Pb) or tin (Sn), a low-temperature solder (such as an indium-based or bismuth-based solder) should be selected to avoid structural changes or local annealing of the superconducting material during high-temperature welding, which could affect its superconducting properties. For superconducting thin foils with high thermal stability or used as support structures, silver-based or eutectic solders can also be used to achieve a higher-strength connection. The welding process is preferably performed under inert gas protection or in a vacuum environment to prevent oxidation and ensure the purity and bonding strength of the welding interface, thereby improving the thermal conductivity efficiency and mechanical stability of the overall structure.

[0028] According to a superconducting thermal switch of the present invention, the coil 20 is a solenoid coil 20 or a Helmholtz coil 20 wound with a superconducting wire. When the magnetic field of the coil 20 is higher than the critical magnetic field when magnetized, or lower than the critical magnetic field when demagnetized, the state of the superconductor 10 changes, the thermal conductivity changes accordingly, and the state of the superconducting thermal switch switches accordingly. When energized, the coil 20 generates a uniform magnetic field in the axial direction, acting on the thin foil-shaped superconductor 10. When the applied magnetic field intensity exceeds the critical magnetic field (H) of the superconductor 10, the coil 20 changes state. c ), superconductor 10 transitions from a superconducting state to a normal state, electrons regain their ability to conduct heat, and thermal conductivity rapidly increases, achieving the "ON" state of the thermal switch. Conversely, when coil 20 is de-energized and the magnetic field is removed, superconductor 10 returns to a superconducting state. Electrons now form Cooper pairs, phonons become the dominant heat conduction mechanism, and thermal conductivity plummets, achieving the "OFF" state. By precisely controlling the on / off current in coil 20, the thermal conductivity of superconductor 10 can be regulated, thereby enabling controlled switching of the heat flow path.

[0029] Furthermore, the superconducting coil 20 offers advantages such as low power consumption, magnetic field stability, and fast response, making it particularly suitable for applications such as space cryogenic systems, where energy efficiency and reliability are critical. While the solenoid coil 20 is suitable for centralized magnetic field control, the Helmholtz coil 20 provides a more uniform magnetic field distribution, improving magnetic field consistency within the superconductor 10 region and thus enhancing the stability and repeatability of thermal switching.

[0030] According to a superconducting thermal switch of the present invention, the thickness of the superconductor 10 in the form of a thin foil is less than or equal to 0.1 mm; the superconducting material constituting the superconductor 10 is any of aluminum, zinc, lead, tin, and indium. The present invention also provides a method in which the purity of the superconducting material is greater than or equal to 99.999%. Specifically, the use of high-purity (≥99.999%) type I superconducting metal materials can significantly reduce the influence of the impurity scattering effect on the change in thermal conductivity of the superconductor 10 between the ON state and the OFF state, thereby improving the thermal response contrast and switching efficiency of the thermal switch in the two states. At the same time, processing the superconducting material into a thin foil structure with a thickness not exceeding 0.1 mm not only helps to reduce the influence of the flux freezing effect, but also enhances the magnetic field penetration ability and response uniformity, ensuring that the superconductor 10 can achieve a rapid transition from the superconducting state to the normal state under a lower magnetic field. In addition, if Figure 1 and Figure 2 As shown in , the superconducting foil is further processed into a specific shape so that the heat flow direction in some areas is perpendicular to the direction of the applied magnetic field, thereby optimizing the relationship between the heat conduction path and the magnetic field. This allows the thermal conductivity of this area to be more effectively regulated under the action of the magnetic field, further improving the thermal isolation ability and working stability of the thermal switch.

[0031] like Figure 2 As shown, according to a superconducting thermal switch of the present invention, the superconductor 10 is arranged in a zigzag or serpentine shape in the coil 20. This arrangement can effectively increase the total length of the superconductor 10 in a limited space, thereby improving the overall heat conduction capacity, while maintaining a compact structure, which is convenient for integration into a space-constrained ultra-low temperature system. The zigzag or serpentine structure can also enhance the interaction area between the magnetic field and the superconductor 10, more evenly covering the entire superconductor 10 area under the same magnetic field strength, which helps to improve the consistency and response speed of the thermal switch switching. In addition, this structural form is conducive to optimizing the heat flow path, making part of the heat flow direction perpendicular to the magnetic field direction, and also helps to reduce the influence of flux freezing, further enhancing the regulation effect of the magnetic field on the superconducting state-normal state transition, and improving the thermal switch performance.

[0032] Furthermore, according to a superconducting thermal switch of the present invention, the superconductor 10 includes a plurality of parallel portions 12 perpendicular to the axial direction and a turning portion 13 connected between adjacent parallel portions 12; the total length of the parallel portions 12 is greater than the total length of the turning portion 13. Specifically, the parallel portion 12 serves as the main heat conduction area, and its length is dominant, ensuring that most of the heat flow path is in a state perpendicular to the direction of the magnetic field, thereby maximizing the use of the magnetic field to control the change in thermal conductivity and achieve an efficient thermal switch function. The turning portion 13 plays a connecting role, making the overall structure continuous and stable, while minimizing the problem of increased local thermal resistance or uneven magnetic field distribution caused by bending. By reasonably designing the proportional relationship and geometric shape of the parallel portion 12 and the turning portion 13, the thermal conductivity of the thermal switch in the ON state and the thermal insulation performance in the OFF state can be further optimized, thereby improving its applicability and reliability in space ultra-low temperature refrigeration systems.

[0033] According to a superconducting thermal switch according to the present invention, a magnetic shielding layer 21 is disposed outside the coil 20. Magnetic shielding layer 21 is made of a high-permeability material, such as pure iron, an iron-cobalt alloy, or silicon steel. Magnetic shielding layer 21 effectively limits the distribution of the magnetic field generated when coil 20 is energized, preventing it from spreading outward and interfering with surrounding cryogenic devices (such as salt pills or other sensitive components). By employing a shielding structure constructed of high-permeability materials, the magnetic field's directivity is significantly improved, enhancing its concentration within the superconductor 10 region. This improves the thermal switch's switching efficiency and response speed, while also reducing the background magnetic field strength required to maintain the OFF state. This further minimizes the overall system's risk of magnetic contamination and enhances the device's compatibility and stability in the ultra-low temperature environment of space.

[0034] Furthermore, according to a superconducting thermal switch of the present invention, the magnetic shielding layer 21 covers at least the outer peripheral surface of the coil 20 and the two ends of the axial direction of the coil 20. The all-round coverage magnetic shielding design can suppress the leakage of the magnetic field to the greatest extent, ensure that the magnetic field is mainly concentrated in the area where the superconductor 10 is located, and avoid ineffective energy consumption and magnetic interference of adjacent components caused by magnetic field dissipation. Covering the outer peripheral surface of the coil 20 can prevent the radial magnetic field from diffusing, while covering the two axial ends can help suppress the overflow of the magnetic field in the axial direction, forming a more uniform and controllable magnetic field environment, which is conducive to improving the consistency and repeatability of the switching of the superconductor 10 between the ON / OFF states. In addition, the structure of the magnetic shielding layer 21 can be designed in sections or integrally formed according to the actual installation space to take into account both the shielding effect and the convenience of assembly.

[0035] The present invention also provides a space cryogenic system. The space cryogenic system provided by the present invention is described below. The space cryogenic system described below and the superconducting thermal switch described above can be referred to in correspondence with each other.

[0036] The space cryogenic system includes a heat sink; an adiabatic demagnetization refrigerator equipped with a salt pellet; and a superconducting thermal switch according to the aforementioned embodiment, positioned between the salt pellet and the heat sink. By integrating the aforementioned superconducting thermal switch between the salt pellet and the heat sink, the space cryogenic system achieves controllable switching of the heat conduction path. The superconducting thermal switch utilizes the significant difference in thermal conductivity between the superconducting and normal states of the superconductor 10 to achieve thermal connection (ON) and disconnection (OFF) under magnetic field control. This precisely controls the effective heat removal from the salt pellet during the magnetization phase and the establishment of adiabatic conditions during the demagnetization phase. This system is suitable for space exploration equipment that requires stable operating temperatures below 100 mK in microgravity environments, offering advantages such as high reliability, long life, and low magnetic interference.

[0037] According to the space cryogenic system of the preferred embodiment of the present application, the copper joint 11 of the superconducting thermal switch is connected to the radiator and the salt pill of the adiabatic demagnetization refrigerator respectively, and the final temperature of the radiator will be maintained at a temperature far less than (0.1T c The salt pill is initially cooled by a temperature below the critical temperature of superconductor 10 (below the critical temperature of superconductor 10). Initially, when the heat sink temperature is above the critical temperature of superconductor 10, superconductor 10 is in a normal state, the thermal switch is in the ON state, and the salt pill and heat sink cool synchronously. When the heat sink temperature drops below the critical temperature of superconductor 10, superconductor 10 transitions to a superconducting state, and the thermal switch transitions to the OFF state. Current is then passed through coil 20, generating an axial magnetic field within the solenoid, the magnitude of which is controlled to be slightly above the critical magnetic field of superconductor 10. After the magnetic field is applied, superconductor 10 transitions from the superconducting state to a normal state, and the thermal switch transitions from the OFF state to the ON state, exciting the salt pill and causing the generated magnetized heat to flow to the heat sink until the salt pill temperature drops to near the heat sink temperature and stabilizes. The magnetic field of the superconducting thermal switch is then removed, causing superconductor 10 to transition from a normal state to a superconducting state, and the superconducting thermal switch transitions from the ON state to the OFF state. At this point, the salt pill is in an adiabatic state. The magnetic field of the salt pill is then gradually removed, and the salt pill begins adiabatic demagnetization cooling. The entire process can be repeated periodically to achieve intermittent ultra-low temperature refrigeration, meeting the continuous demand for high-precision, high-stability ultra-low temperature environment in space science exploration missions.

[0038] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or modes and features of different embodiments or modes described in this specification without contradiction.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A superconducting thermal switch, characterized in that: include: A superconductor (10) in the form of a thin foil, wherein both ends of the superconductor (10) are respectively provided with connection structures, wherein the connection structure at one end is used for connecting to a salt pill, and the connection structure at the other end is used for connecting to a radiator; The coil (20) is arranged around the circumferential direction of the superconductor (10), and when the coil (20) is energized, an axial magnetic field is formed at the center of the coil (20), and at least a portion of the superconductor (10) is perpendicular to the axial direction, so that the heat flow direction of the portion of the superconductor (10) is perpendicular to the magnetic field direction.

2. The superconducting thermal switch according to claim 1, characterized in that: The connection structure comprises a copper joint (11), and the copper joints (11) at both ends of the superconductor (10) are detachably connected to the salt pill and the radiator, respectively.

3. The superconducting thermal switch according to claim 2, characterized in that: The copper joint (11) is connected to the end of the superconductor (10) by welding.

4. The superconducting thermal switch according to claim 1, characterized in that: The coil (20) is a solenoid coil (20) or a Helmholtz coil (20) wound by a superconducting wire.

5. The superconducting thermal switch according to claim 1, characterized in that: The thickness of the thin foil-shaped superconductor (10) is less than or equal to 0.1 mm.

6. The superconducting thermal switch according to any one of claims 1 to 5, characterized in that: The superconductor (10) is arranged in a zigzag or serpentine shape within the coil (20).

7. The superconducting thermal switch according to claim 6, characterized in that: The superconductor (10) includes a plurality of parallel portions (12) perpendicular to the axial direction and a turning portion (13) connecting adjacent parallel portions (12); The total length of the parallel portion (12) is greater than the total length of the turning portion (13).

8. The superconducting thermal switch according to any one of claims 1 to 5, characterized in that: A magnetic shielding layer (21) is provided on the outside of the coil (20).

9. The superconducting thermal switch according to claim 8, characterized in that: The magnetic shielding layer (21) covers at least the outer peripheral surface of the coil (20) and both ends of the coil (20) in the axial direction.

10. A space cryogenic system, characterized in that: include: heat sink; Adiabatic demagnetization refrigerator, equipped with salt pellets; The superconducting thermal switch according to any one of claims 1 to 9, wherein the superconducting thermal switch is disposed between the salt pill and the heat sink.

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