Superconducting thermal switch and space extremely low temperature system
By combining a thin foil superconductor with a coil, a superconducting thermal switch has been developed, which solves the problem of unsatisfactory performance of traditional thermal switches in extremely low temperature environments. This enables stable and efficient thermal switch control in space probes and is suitable for space cryogenic systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TECHNICAL INST OF PHYSICS & CHEMISTRY - CHINESE ACAD OF SCI
- Filing Date
- 2025-05-30
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional thermal switches do not perform well in extremely low temperature environments and cannot meet the requirements of space probes for temperatures below 100 mK. They also suffer from mechanical wear, magnetic interference, and high sustaining magnetic fields.
By combining a thin foil-shaped superconductor with a coil, an axial magnetic field is generated by controlling the coil to make the heat flow direction of the superconductor perpendicular to the magnetic field, thus achieving rapid control of thermal conductivity. The design has no mechanical moving parts and utilizes the difference in thermal conductivity between the superconducting state and the normal state to realize the thermal switching function.
It achieves stable and efficient thermal connection and disconnection control in extremely low temperature environments, avoiding mechanical wear and magnetic interference, and is suitable for space cryogenic systems, with long life and high reliability.
Smart Images
Figure CN224230370U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of cryogenic refrigeration technology, and in particular to a superconducting thermal switch and a space cryogenic system. Background Technology
[0002] In the field of cryogenic refrigeration technology, especially for applications requiring temperatures below 1 K, several techniques, including adsorption refrigeration, dilution refrigeration, and adiabatic demagnetization refrigeration, are widely used. Modern space probes, such as superconducting edge transducers and X-ray microcalorimeters, require operating temperatures as low as below 100 mK. Adsorption refrigeration can only achieve a minimum of 260 mK, which is insufficient for such probes. Dilution refrigeration and adiabatic demagnetization refrigeration can achieve temperatures as low as around 2 mK; however, conventional dilution refrigerators rely on gravity, limiting their effectiveness in space applications. In contrast, adiabatic demagnetization refrigerators, unaffected by microgravity, have become a key refrigeration method for achieving temperatures below 100 mK in space environments.
[0003] The core of operating an adiabatic demagnetizing refrigerator lies in its internal thermal switch performance, the quality of which directly affects the overall efficiency of the unit. This process involves the effective removal of the magnetization heat generated during the magnetization of the salt pellets and the precise control of ensuring the salt pellets are in an adiabatic state to produce a cooling effect during subsequent magnetic field removal. Traditional thermal switch types include mechanical, air-gap, and reluctance types, but each has its shortcomings: mechanical thermal switches are unsuitable for space applications due to their complex internal structure and susceptibility to damage from frequent operation; air-gap thermal switches can only operate effectively at temperatures above 200 mK; and reluctance thermal switches require a large open state to maintain the magnetic field, which may interfere with other components within the cryogenic system. Therefore, the performance of traditional thermal switch solutions in the field of cryogenic refrigeration technology is not ideal. Utility Model Content
[0004] This invention provides a superconducting thermal switch and a space cryogenic system to address the shortcomings of traditional thermal switches in the prior art, which have unsatisfactory performance in cryogenic environments, and to achieve stable and efficient thermal connection and disconnection control in cryogenic environments.
[0005] This invention provides a superconducting thermal switch, comprising: a superconductor in the form of a thin foil, wherein connecting structures are respectively provided at both ends of the superconductor, wherein the connecting structure at one end is used to connect a salt pellet and the connecting structure at the other end is used to connect a heat sink; a coil arranged around the circumference of the superconductor, wherein when the coil is energized, an axial magnetic field is formed at the center position of the coil, and at least a portion of the superconductor is perpendicular to the axial direction, such that the heat flow direction of this portion of the superconductor is perpendicular to the magnetic field direction.
[0006] According to one embodiment of the present invention, the connection structure includes copper connectors, and the copper connectors at both ends of the superconductor are detachably connected to the salt pellet and the heat sink, respectively.
[0007] According to one embodiment of the present invention, the copper connector 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 with superconducting wire.
[0009] According to one embodiment of the present invention, the thickness of the superconductor, which is in the form of a thin foil, 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 a bend connecting adjacent parallel portions; the total length of the parallel portions is greater than the total length of the bend.
[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 peripheral surface of the coil and both ends of the coil in the axial direction.
[0014] This utility model also provides a space cryogenic system, including: a radiator; an adiabatic demagnetizing refrigerator with salt pellets; and a superconducting thermal switch according to the above embodiment, wherein the superconducting thermal switch is disposed between the salt pellets and the radiator.
[0015] This invention provides a superconducting thermal switch and a space cryogenic system. By employing a thin foil-shaped superconductor as the core heat transfer element and connecting it to a salt pellet and a heat sink at its two ends, and combining this with an axial magnetic field generated by coils arranged around the circumference of the superconductor, at least a portion of the superconductor is perpendicular to the magnetic field direction. This design ensures that the heat flow direction of this portion of the superconductor is perpendicular to the magnetic field direction, effectively controlling its transition from a superconducting state to a normal state under the influence of the magnetic field, thereby significantly altering its thermal conductivity and achieving ON / OFF switching of the thermal switch. This structure not only possesses advantages such as long lifespan and high reliability, avoiding mechanical wear problems, but also utilizes superconducting materials with low critical magnetic fields, enabling stable operation at extremely low temperatures without generating strong magnetic interference to the salt pellet or other cryogenic components. It is particularly suitable for adiabatic demagnetizing refrigeration systems in space cryogenic environments, meeting the demands of modern space cryogenic systems for high-performance thermal switches. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the structure of the superconducting thermal switch provided by this utility model.
[0018] Figure 2 This is a schematic diagram of the superconductor structure of the superconducting thermal switch provided by this utility model.
[0019] Figure label:
[0020] 10. Superconductor; 11. Copper connector; 12. Parallel section; 13. Turning section; 20. Coil; 21. Magnetic shielding layer. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.
[0022] In the description of the embodiments of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should also be noted that in the description of this utility model, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0023] The following is combined Figures 1-2 This invention describes the specific implementation of the superconducting thermal switch.
[0024] like Figure 1 As shown, this utility model provides a superconducting thermal switch, comprising: a superconductor 10, which is in the form of a thin foil, meaning the superconductor 10 is processed into a very thin sheet or foil shape; connecting structures are respectively provided at both ends of the superconductor 10, one end of which is used to connect a salt pellet, and the other end of which is used to connect a heat sink; a coil 20, arranged around the circumference of the superconductor 10; 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 this portion of the superconductor 10 is perpendicular to the magnetic field direction. Specifically, this 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 the superconducting state (i.e., the temperature is below its critical temperature T), the thermal switch achieves the thermal switching function. c And the applied magnetic field is less than its critical magnetic field H c When electrons form Cooper pairs and no longer participate in heat conduction, phonons become the main heat conduction mechanism, leading to a significant decrease in thermal conductivity. However, when coil 20 is energized to generate a sufficiently strong magnetic field, the superconductor 10 partially or entirely enters a normal state (i.e., the magnetic field exceeds H0). c Electrons re-engage in heat conduction, causing a rapid increase in thermal conductivity, thus achieving a high thermal conductivity state in the "ON" state. By controlling the on / off state of the current in coil 20, the thermal conductivity state of superconductor 10 can be adjusted, thereby enabling the on / off state of heat flow. Compared with mechanical thermal switches, the superconducting thermal switch of this embodiment has a longer lifespan and higher reliability, avoiding mechanical wear problems caused by frequent operation; compared with air-gap thermal switches, it has a lower operating lower limit temperature and can operate stably at 100 mK or even below a few milliklvin; compared with magnetoresistive thermal switches, it requires a smaller magnetic field to maintain the OFF state, thus resulting in extremely low magnetic interference and no impact on other sensitive devices in the cryogenic system; at the same time, compared with similar thermal switches, this invention, through optimizing the direction of magnetic field application and the structural design of superconductor 10, can effectively avoid the problem of high thermal conductivity in the OFF state caused by magnetic flux freezing, further improving the thermal switching performance.
[0025] In use, this superconducting thermal switch is applied to the adiabatic demagnetizing refrigerator in a space cryogenic refrigeration system. During the magnetization phase, the salt pellet generates heat due to magnetization. At this time, coil 20 is energized, keeping the superconductor 10 in a normal state, maintaining high thermal conductivity. This ensures that the magnetization heat generated by the salt pellet can be efficiently conducted through the superconductor 10 to the heat sink and dissipated. When the salt pellet cools to the target temperature, the current to coil 20 is cut off, and the superconductor 10 returns to the superconducting state. The thermal conductivity drops sharply, forming a thermal isolation state, making the salt pellet and the heat sink thermally insulated. Subsequently, the magnetic field is gradually removed, and the salt pellet begins to cool down, achieving the cooling effect. This process can be repeated periodically to meet intermittent cooling requirements. Because this thermal switch has no moving mechanical parts, it has a long lifespan and high reliability. Furthermore, it requires a small critical magnetic field and will not cause significant magnetic interference to the salt pellet or other cryogenic devices, making it particularly suitable for space applications in microgravity environments.
[0026] Furthermore, the superconductor 10 of the aforementioned superconducting thermal switch preferably uses type I superconducting materials, such as lead (Pb), tin (Sn), or indium (In) foil, which have low critical magnetic fields and good processing performance, enabling stable operation in an extremely low temperature range of a few milliklvin to hundreds of milliklvin. The coil 20 can use high-temperature superconducting windings or ordinary copper windings, selected according to actual operating temperature and power consumption requirements. The connection structure can be designed as welded, crimped, or flexible leads to adapt to different installation conditions and the effects of thermal shrinkage deformation. In addition, a temperature sensor and feedback control system can be integrated to achieve real-time monitoring and automatic switching control of the thermal switch status, improving the system's intelligence level and operational stability.
[0027] According to this utility model, a superconducting thermal switch includes a connection structure comprising copper connectors 11. The copper connectors 11 at both ends of the superconductor 10 are detachably connected to the salt pellet and the heat sink, respectively. These copper connectors 11 serve as a transition interface for heat conduction, ensuring good thermal contact performance between the superconductor 10 and the salt pellet and heat sink. They are also detachable, facilitating installation, replacement, or maintenance. The connection method between the copper connectors 11 and the superconductor 10 is preferably a low-thermal-resistance, high-stability welding method, which maintains structural integrity and heat conduction efficiency in extremely low-temperature environments, thereby ensuring reliable operation of the thermal switch under extreme conditions.
[0028] Furthermore, according to the superconducting thermal switch of this invention, the copper connector 11 is connected to the end of the superconductor 10 by welding. The welding temperature and solder selection can be determined based on the properties of the superconducting material of the selected superconductor 10. When the superconductor 10 uses type I superconducting materials with low melting points such as lead (Pb) or tin (Sn), a low-temperature solder (such as indium-based or bismuth-based solder) should be selected to avoid microstructural changes or localized annealing of the superconducting material during high-temperature welding, which would affect its superconducting performance. For superconducting foils with high thermal stability or used as supporting structures, silver-based or eutectic solders can also be used for higher-strength connections. The welding process is preferably carried out under inert gas protection or in a vacuum environment to prevent oxidation and ensure the purity and bonding strength of the weld interface, thereby improving the overall thermal conductivity and mechanical stability of the structure.
[0029] According to this invention, a superconducting thermal switch uses a coil 20 that is either a solenoid coil 20 or a Helmholtz coil wound with superconducting wire. When the coil 20 is magnetized, if the magnetic field exceeds the critical magnetic field, or when the magnetic field is demagnetized, if the magnetic field falls below the critical magnetic field, the state of the superconductor 10 changes, the thermal conductivity changes accordingly, and the superconducting thermal switch state switches accordingly. After being energized, the coil 20 generates a uniform magnetic field along the axial direction, acting on the foil-shaped superconductor 10. When the applied magnetic field strength exceeds the critical magnetic field (Hc) of the superconductor 10... c When the current in coil 20 is turned off, the superconductor 10 transitions from the superconducting state to the normal state, electrons regain their thermal conductivity, and the thermal conductivity rises rapidly, achieving the "ON" state of the thermal switch. Conversely, when the current in coil 20 is turned off and the magnetic field is removed, the superconductor 10 returns to the superconducting state. At this time, electrons form Cooper pairs, phonons become the dominant thermal conduction mechanism, and the thermal conductivity drops significantly, achieving the "OFF" state. By precisely controlling the on / off state of the current in coil 20, the thermal conductivity of the superconductor 10 can be regulated, thereby achieving controllable switching of the heat flow channel.
[0030] Furthermore, the coil 20, wound with superconducting wire, offers advantages such as low power consumption, magnetic field stability, and fast response speed, making it particularly suitable for applications in cryogenic space systems where energy consumption and reliability requirements are high. 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.
[0031] According to this invention, a superconducting thermal switch is provided, wherein the thickness of the foil-shaped superconductor 10 is less than or equal to 0.1 mm; the superconducting material constituting the superconductor 10 is any one of aluminum, zinc, lead, tin, and indium. This invention also provides a method where the purity of the superconducting material is greater than or equal to 99.999%. Specifically, using a high-purity (≥99.999%) Type I superconducting metal material can significantly reduce the influence of impurity scattering effects on the change in thermal conductivity of the superconductor 10 between the ON and OFF states, thereby improving the thermal response contrast and switching efficiency of the thermal switch in the two states. Simultaneously, processing the superconducting material into a foil structure with a thickness not exceeding 0.1 mm not only helps to reduce the influence of the magnetic flux freezing effect but also enhances the magnetic field penetration capability and response uniformity, ensuring that the superconductor 10 can achieve a rapid transition from the superconducting state to the normal state even under a lower magnetic field. Furthermore, as... Figure 1 and Figure 2 As shown, the superconducting foil is further processed into a specific shape so that the heat flow direction in a certain area 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 the area to be more effectively controlled under the action of the magnetic field, further improving the thermal break-off capability and operational stability of the thermal switch.
[0032] like Figure 2 As shown, according to the present invention, in a superconducting thermal switch, the superconductor 10 is arranged in a zigzag or serpentine pattern within the coil 20. This arrangement effectively increases the total length of the superconductor 10 within a limited space, thereby improving the overall thermal conductivity while maintaining a compact structure, facilitating integration into space-constrained cryogenic systems. The zigzag or serpentine structure also enhances the interaction area between the magnetic field and the superconductor 10, more uniformly covering the entire superconductor 10 region under the same magnetic field strength, which helps improve the consistency and response speed of thermal switching. Furthermore, this structural form is beneficial for optimizing the heat flow path, making part of the heat flow direction perpendicular to the magnetic field direction, which also helps reduce the influence of magnetic flux freezing, further enhancing the control effect of the magnetic field on the superconducting-normal state transition, and improving thermal switching performance.
[0033] Furthermore, according to a superconducting thermal switch of this invention, the superconductor 10 includes multiple parallel portions 12 perpendicular to the axial direction and a turning portion 13 connecting 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 portions 12, as the main heat conduction area, have a dominant length, ensuring that most of the heat flow path is perpendicular to the magnetic field direction, thereby maximizing the use of the magnetic field to control changes in thermal conductivity and achieving a highly efficient thermal switching function. The turning portion 13 serves as a connector, 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 rationally designing the proportional relationship and geometric shape of the parallel portions 12 and the turning portion 13, the thermal conductivity in the ON state and the thermal insulation performance in the OFF state of the thermal switch can be further optimized, improving its applicability and reliability in space cryogenic refrigeration systems.
[0034] According to the present invention, a superconducting thermal switch has a magnetic shielding layer 21 disposed on the outer side of the coil 20. The magnetic shielding layer 21 is made of a high magnetic permeability material, which can be any one of pure iron, iron-cobalt alloy, or silicon steel. The magnetic shielding layer 21 is used to effectively limit the distribution range of the magnetic field generated when the coil 20 is energized, preventing the magnetic field from spreading outward and interfering with surrounding low-temperature devices (such as salt pellets or other sensitive components). By using a shielding structure made of a high magnetic permeability material, the magnetic field guidance can be significantly improved, and the concentration of the magnetic field in the superconductor 10 region can be enhanced, thereby improving the switching efficiency and response speed of the thermal switch. At the same time, the background magnetic field strength required to maintain the OFF state is reduced, further reducing the overall magnetic contamination risk of the system and improving the compatibility and stability of the equipment in the extremely low temperature environment of space.
[0035] Furthermore, according to the superconducting thermal switch of this invention, 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. This all-around magnetic shielding design can suppress magnetic field leakage to the greatest extent, ensuring that the magnetic field is mainly concentrated in the area where the superconductor 10 is located, avoiding ineffective energy consumption and magnetic interference from adjacent components due to magnetic field dissipation. Covering the outer peripheral surface of the coil 20 prevents radial magnetic field diffusion, while covering both ends in the axial direction helps suppress magnetic field overflow along the axial direction, forming a more uniform and controllable magnetic field environment, which is beneficial to improving the consistency and repeatability of the superconductor 10 switching between ON / OFF states. In addition, the structure of the magnetic shielding layer 21 can be designed in segments or integrally molded according to the actual installation space to balance shielding effectiveness and assembly convenience.
[0036] This utility model also provides a space cryogenic system. The space cryogenic system provided by this utility model is described below. The space cryogenic system described below can be referred to in correspondence with the superconducting thermal switch described above.
[0037] The space cryogenic system includes: a heat sink; an adiabatic demagnetizing refrigerator equipped with salt pellets; and a superconducting thermal switch as described above, positioned between the salt pellets and the heat sink. This space cryogenic system achieves controllable switching of the heat conduction path by integrating the aforementioned superconducting thermal switch between the salt pellets and the heat sink. The superconducting thermal switch utilizes the significant difference in thermal conductivity between the superconductor 10 in its superconducting and normal states to achieve thermal connection (ON state) and disconnection (OFF state) under magnetic field control, thereby precisely controlling the effective heat dissipation of the salt pellets during the magnetization phase and the establishment of adiabatic conditions during the demagnetization phase. This system is suitable for space exploration equipment requiring stable operation temperatures below 100 mK in microgravity environments, offering advantages such as high reliability, long lifespan, and low magnetic interference.
[0038] According to the preferred embodiment of the space cryogenic system of this application, the copper connector 11 of the superconducting thermal switch is connected to the heat sink and the salt pellets of the adiabatic demagnetizing refrigerator, respectively, and the final temperature of the heat sink will be maintained at a level much less than (0.1T). c The following describes a temperature 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 ON, and the salt pellet and heat sink cool down 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 becomes OFF. At this time, current is passed through coil 20, generating an axial magnetic field inside the solenoid. The magnitude of the magnetic field is controlled to be slightly higher than the critical magnetic field of superconductor 10. After applying the magnetic field, superconductor 10 transitions from a superconducting state to a normal state, the thermal switch changes from OFF to ON, and the salt pellet is energized. The generated magnetization heat flows to the heat sink until the salt pellet temperature drops to near the heat sink temperature and stabilizes. Then, the magnetic field of the superconducting thermal switch is removed, and superconductor 10 transitions from a normal state to a superconducting state. The superconducting thermal switch changes from ON to OFF, and the salt pellet is in an adiabatic state. Then, the magnetic field of the salt pellet is gradually removed, and the salt pellet begins adiabatic demagnetization cooling process. The entire process can be repeated periodically to achieve intermittent cryogenic cooling, meeting the continuous demand for high-precision, high-stability cryogenic environments in space science exploration missions.
[0039] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "method," "specific method," or "some methods," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or method is included in at least one embodiment or method of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or method. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or methods. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or methods described in this specification, as well as the features of different embodiments or methods.
[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. A superconducting thermal switch, characterized in that, include: A superconductor (10) is in the form of a thin foil. A connection structure is provided at both ends of the superconductor (10). The connection structure at one end is used to connect a salt pellet, and the connection structure at the other end is used to connect a heat sink. A coil (20) is arranged around the circumference of the superconductor (10). When the coil (20) is energized, an axial magnetic field is formed at the center of the coil (20). 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.
2. The superconducting thermal switch according to claim 1, characterized in that, The connection structure includes copper connectors (11), and the copper connectors (11) at both ends of the superconductor (10) are detachably connected to the salt pellet and the heat sink, respectively.
3. The superconducting thermal switch according to claim 2, characterized in that, The copper connector (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 with superconducting wire.
5. The superconducting thermal switch according to claim 1, characterized in that, The thickness of the superconductor (10), which is in the form of a thin foil, 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 bend (13) connecting adjacent parallel portions (12). The total length of the parallel section (12) is greater than the total length of the turning section (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; A thermal demagnetizing refrigeration unit equipped with salt tablets; The superconducting thermal switch as described in any one of claims 1 to 9, wherein the superconducting thermal switch is disposed between the salt pellet and the heat sink.