Superconducting magnet and mockup for plasma confinement

Abstract

This invention discloses a superconducting magnet and simulation device for plasma confinement. The superconducting magnet includes: a frame on which superconducting coils are mounted, the superconducting coils including a central coil and end coils; a cooling medium tank, a cold shield, and a vacuum Dewar inner cylinder are sequentially arranged outside the frame; a superconducting power supply, including a first superconducting power supply and a second superconducting power supply, the first superconducting power supply simultaneously supplies power to the central coil and end coils, and the second superconducting power supply supplies power to the end coils when needed; a protection diode connected in parallel across the two ends of the central coil and the two ends of the end coils; a radial lifting rod disposed on the outside of the frame; and an axial lifting rod parallel to the axis of the frame. This invention not only achieves adjustable magnetic field uniformity but also effectively ensures the safety of the superconducting magnet in the event of magnet quenching, while reducing the impact of heat leakage while meeting the protection requirements for lifting and transportation.

Description

Technical Field

[0001] This invention relates to the field of superconducting equipment technology, and in particular to a superconducting magnet and simulation device for plasma confinement. Background Technology

[0002] Nuclear fusion research is a major international collaborative project undertaken by the global scientific community to address humanity's future energy challenges. Unlike non-renewable and conventional clean energy, fusion energy boasts advantages such as unlimited resources, no environmental pollution, and no production of high-level radioactive nuclear waste. It is one of the dominant forms of energy for humanity's future and a crucial pathway recognized to ultimately solve human society's energy and environmental problems, promoting sustainable development. The International Thermonuclear Experimental Reactor (ITER) project is one of the world's largest and most far-reaching international scientific research collaborations, requiring approximately 10 years to build and costing $5 billion. The ITER device is a superconducting tokamak capable of generating large-scale nuclear fusion reactions, commonly known as an "artificial sun." The ITER project is an essential step towards the commercialization of fusion energy, aiming to verify the scientific and technological feasibility of peacefully utilizing fusion energy. The ITER project integrates the major scientific and technological achievements of current international research on controlled magnetic confinement nuclear fusion, possessing reliable scientific evidence and a solid technological foundation.

[0003] As a core component of the magnetic confinement fusion reactor, the divertor is an integral part of toroidal fusion devices (such as tokamak). This device diverts charged particles from the outer discharge layer into a separate chamber where they bombard baffles, becoming neutral particles and being extracted. This method prevents high-energy particles in the outer layer from bombarding the main discharge chamber walls, thus avoiding the release of secondary particles that could cool the discharge. Therefore, studying its performance under plasma conditions is crucial for the successful design and manufacture of commercially viable divertors.

[0004] However, studying the material performance of divertors in a plasma environment requires building a large-scale experimental platform to simulate plasma-related parameters under real nuclear fusion conditions. The core component of the experimental platform—the large-scale superconducting high-power magnet device—is difficult to design, manufacture, and operate due to its high risks, resulting in a lack of relevant basic research and technological accumulation in China. Moreover, even if existing magnet devices can complete the simulation, the following problems exist: (1) the magnetic field uniformity cannot be adjusted, which cannot meet the constraint and control requirements of plasmas with different working fluids; (2) the superconducting magnet stores a large amount of energy, and after the magnet loses quench, a large amount of energy is released in a short time, which may cause the magnet to burn out; (3) the hoisting structure used cannot meet the requirements of stress and transportation protection while minimizing heat leakage. Summary of the Invention

[0005] This invention provides a superconducting magnet and simulation device for plasma confinement, which solves the problems of existing magnet devices, such as the inability to adjust the magnetic field uniformity, magnet burnout after quenching, and the inability of the hoisting structure to simultaneously minimize heat leakage and meet the requirements for stress and transportation protection.

[0006] On one hand, embodiments of the present invention provide a superconducting magnet for plasma confinement, comprising:

[0007] The skeleton is equipped with superconducting coils, which include a central coil and end coils. The two end coils are respectively located at the two ends of the skeleton, and the central coil is located between the two end coils. The skeleton is equipped with a cooling medium tank, a cold shield, and a vacuum Dewar inner cylinder in sequence.

[0008] The superconducting power supply includes a first superconducting power supply and a second superconducting power supply. The first superconducting power supply supplies power to the middle coil and the end coil simultaneously, and the second superconducting power supply supplies power to the end coil when needed.

[0009] A protection diode is connected in parallel across the two ends of the middle coil and the two ends of the end coil.

[0010] A radial lifting rod is set on the outside of the frame. The radial lifting rod passes through the cooling medium tank, the cold shield and the inner cylinder of the vacuum Dewar, and extends out of the outer part of the inner cylinder of the vacuum Dewar.

[0011] The axial lifting rod is parallel to the axis of the frame. The axial lifting rod passes through the cooling medium tank, the cold shield and the vacuum Dewar inner cylinder, and extends outside the vacuum Dewar inner cylinder.

[0012] On the other hand, embodiments of the present invention provide a simulation device for plasma confinement, including an ion source, a test sample, and the aforementioned superconducting magnet for plasma confinement. The ion source is positioned facing the test sample, and the ion source and the test sample are arranged inside the superconducting magnet along its axial direction.

[0013] The superconducting magnet and simulation device for plasma confinement disclosed in this invention have the following advantages:

[0014] 1. Based on the requirements of magnetic field distribution in superconducting magnets and the requirements of plasma confinement, a multi-coil superconducting magnet design structure is proposed. According to actual usage requirements, the uniformity of the magnetic field can be flexibly adjusted by energizing the end coils.

[0015] 2. The introduction of a suspension tie rod structure avoids excessive heat leakage in the low-temperature system, while also ensuring the reliability of the magnet under stress and during transportation.

[0016] 3. A method of opening heat-conducting seams on the cold screen was proposed to avoid excessive cooling stress that could damage the internal structure of large magnets when they lose their overheating state.

[0017] 4. Introducing a quench protection diode scheme to achieve segmented protection of the entire magnet, reducing the excessive voltage after the superconducting magnet quenches and preventing damage to the magnet. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A cross-sectional view of a superconducting magnet for plasma confinement provided in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the structure of the superconducting coil, frame, and cryogenic cooler provided in an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the structure of a traditional cold screen;

[0022] Figure 4 This is a schematic diagram of the structure of a cold screen provided in an embodiment of the present invention;

[0023] Figure 5 A circuit connection diagram of a superconducting magnet for plasma confinement provided in an embodiment of the present invention;

[0024] Figure 6 A schematic diagram illustrating the adjustment of the magnetic field uniformity of a superconducting magnet used for plasma confinement, provided as an embodiment of the present invention;

[0025] Figure 7 A schematic diagram of a simulation device for plasma confinement provided in an embodiment of the present invention;

[0026] Figure 8 This is a schematic diagram of the trajectory of plasma without magnetic field constraint.

[0027] Figure 9 A schematic diagram of the trajectory of plasma in a plasma confinement simulation device provided in an embodiment of the present invention;

[0028] Figure 10 This is a flowchart of a simulation method for a plasma confinement simulation device provided in an embodiment of the present invention.

[0029] Figure labeling: 1-Superconducting magnet, 2-Ion source, 3-Test sample. 101-Refrigerator, 101-A-First-stage cold head, 101-B-Second-stage cold head, 101-C-Condenser, 102-Superconducting coil, 103-Frame, 104-Cooling medium tank, 105-Cold shield, 105-A-Protruding structure, 105-B-Cylinder, 105-C-End plate, 105-D-Connecting hole, 105-E-Heat-conducting seam, 106-Vacuum Dewar inner cylinder, 107-Current lead, 108-Axial lifting rod, 109-Radial lifting rod, 110-Support base, 111-First superconducting power supply, 112-Second superconducting power supply, 113-Protection diode, 114-Circuit breaker. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Figure 1-2 This is a schematic diagram of a superconducting magnet for plasma confinement provided in an embodiment of the present invention. The embodiment of the present invention provides a superconducting magnet for plasma confinement, comprising:

[0032] A frame 103 is provided, on which a superconducting coil 102 is provided. The superconducting coil 102 includes a middle coil and end coils. The two end coils are respectively located at the two ends of the frame 103, and the middle coil is located between the two end coils. A cooling medium tank 104, a cold shield 105, and a vacuum Dewar inner cylinder 106 are sequentially provided on the outside of the frame 103.

[0033] The superconducting power supply includes a first superconducting power supply 111 and a second superconducting power supply 112. The first superconducting power supply 111 supplies power to the middle coil and the end coil simultaneously, and the second superconducting power supply 112 supplies power to the end coil when needed.

[0034] Protection diode 113 is connected in parallel across the two ends of the middle coil and the two ends of the end coil;

[0035] A radial lifting rod 109 is set on the outside of the frame 103. The radial lifting rod 109 passes through the cooling medium tank 104, the cold screen 105 and the vacuum Dewar inner cylinder 106, and extends out of the vacuum Dewar inner cylinder 106.

[0036] The axial lifting rod 108 is parallel to the axis of the frame 103. The axial lifting rod 108 passes through the cooling medium tank 104, the cold screen 105 and the vacuum Dewar inner cylinder 106, and extends out of the vacuum Dewar inner cylinder 106.

[0037] For example, the superconducting magnet 1 is generally formed into a ring-shaped cylindrical structure, wherein the skeleton 103, the cooling medium tank 104, the cold screen 105 and the vacuum Dewar inner cylinder 106 are all ring-shaped cylindrical structures, and the diameters of the skeleton 103, the cooling medium tank 104, the cold screen 105 and the vacuum Dewar inner cylinder 106 increase sequentially, so that they can be nested in sequence.

[0038] A superconducting coil 102 is wound on the outer surface of a frame 103. A central coil COIL1 is wound at the middle of the outer surface of the frame 103, while end coils COIL2 and COIL3 are wound at each end of the outer surface of the frame 103. The end coils COIL2 and COIL3 and the central coil COIL1 can be made of the same material, and the winding thickness of the end coils COIL2 and COIL3 on the frame 103 can be greater than the winding thickness of the central coil COIL1 on the frame 103. Figure 5 and 6 As shown, this enables the end coils COIL2 and COIL3 to generate a stronger magnetic field to compensate for the weakening of the magnetic field at the end of the frame 103.

[0039] The cooling medium tank 104 is used to hold liquid cooling medium, such as liquid helium, to keep the superconducting coil 102 below its superconducting critical temperature at all times. The cooling shield 105 completely encloses the cooling medium tank 104 to reduce the thermal radiation load on the cooling medium tank 104 from the external high-temperature environment.

[0040] In an embodiment of the invention, the tap of the superconducting coil 102 is led out to the outside of the vacuum Dewar inner cylinder 106 via a current lead 107 and electrically connected to a superconducting power supply located outside the vacuum Dewar inner cylinder 106. A protection diode 113 is connected in parallel across the two ends of each of the middle coil COIL1 and the end coils COIL2 and COIL3. This protection diode 113 consists of two diodes connected in reverse parallel. When the superconducting magnet 1 loses quench due to a fault, the protection diode 113 can protect the superconducting coil 102 from excessive voltage, ensuring the safety of the superconducting magnet 1. Furthermore, the first superconducting power supply 111 and the second superconducting power supply 112 supply power to the middle coil COIL1 and the end coils COIL2 and COIL3. The connection of the superconducting power supply can be changed according to the actual magnetic field conditions and requirements, achieving adjustable magnetic field uniformity.

[0041] One end of the radial lifting rod 109 is connected to the side of the frame 103, and the other end passes sequentially through the cooling medium tank 104, the cold screen 105, and the vacuum Dewar inner cylinder 106, extending from the arc-shaped side of the vacuum Dewar inner cylinder 106, facilitating the lifting of the superconducting magnet 1 by the lifting equipment. The radial lifting rod 109 connects to these structures as it passes through the cooling medium tank 104, the cold screen 105, and the vacuum Dewar inner cylinder 106, serving to position these structures and maintain a fixed distance between them. In embodiments of the invention, the radial lifting rods 109 can be in multiple sets, each set containing two radial lifting rods 109. The two radial lifting rods 109 in one set are symmetrically arranged on the sides of the frame 103 about the central radial axis of the frame 103. Multiple sets of radial lifting rods 109 are evenly arranged at multiple positions on the sides of the frame 103 around its axial direction.

[0042] Both ends of the axial lifting rod 108 extend outside the vacuum Dewar inner cylinder 106. After one end is inserted into the vacuum Dewar inner cylinder 106, it first passes through the cold shield 105 and the cooling medium tank 104 in sequence, and then passes through the cooling medium tank 104, the cold shield 105, and the vacuum Dewar inner cylinder 106 in sequence, extending outside the vacuum Dewar inner cylinder 106. The axial lifting rod 108 connects with these structures as it passes through the cooling medium tank 104, the cold shield 105, and the vacuum Dewar inner cylinder 106, serving to position these structures and further maintaining a fixed distance between them. In embodiments of the present invention, there are multiple axial lifting rods 108, which are evenly arranged around the axial direction of the vacuum Dewar inner cylinder 106.

[0043] The present invention employs radial lifting rods 109 and axial lifting rods 108 to connect the cooling medium tank 104, the cold shield 105, and the vacuum Dewar inner cylinder 106 together via the lifting rods. Moreover, there are no other connections besides the lifting rods, which not only ensures the stability of the lifting structure and meets the requirements for stress and transportation protection, but also minimizes the impact of heat leakage as much as possible.

[0044] In one possible embodiment, a refrigerator 101 is provided on the outer surface of the vacuum Dewar inner cylinder 106, and the cold head of the refrigerator 101 is in contact with the superconducting coil 102 through the condenser 101-C.

[0045] For example, the refrigerator 101 can be a GM refrigerator or other types of refrigerators. After the cold head of the refrigerator 101 comes into contact with the superconducting coil 102 through the condenser 101-C, starting the refrigerator 101 can cool the liquid cooling medium in the cooling medium tank 104, thereby keeping the superconducting coil 102 below the superconducting critical temperature at all times.

[0046] In one possible embodiment, the cold head of the refrigerator 101 includes a primary cold head 101-A and a secondary cold head 101-B. The secondary cold head 101-B is in contact with the superconducting coil 102 through the condenser 101-C, and the primary cold head 101-A is in contact with the cold shield 105.

[0047] For example, the cold screen 105 includes: a cylindrical body 105-B; a protruding structure 105-A disposed on the outer side of the cylindrical body 105-B, the protruding structure 105-A having a connecting hole 105-D, a primary cold head 101-A inserted into the connecting hole 105-D and in contact with the protruding structure 105-A, and the primary cold head 101-A also passing through the connecting hole 105-D and connecting to the secondary cold head 101-B.

[0048] Furthermore, the cylinder 105-B has a ring-shaped cylindrical structure, with end plates 105-C at both ends to form a single unit for the cold shield 105. After the primary cold head 101-A comes into contact with the protruding structure 105-A, the refrigeration unit 101 starts to cool the cold shield 105.

[0049] In one possible embodiment, the cylinder 105-B is provided with a plurality of through heat-conducting slits 105-E.

[0050] For example, a traditional cold screen structure such as Figure 3 As shown, its cold shield is a closed structure. In the event of a magnet quench, the liquid cooling medium in the cooling medium tank 104 becomes gaseous due to temperature rise, and its volume increases rapidly, leading to damage to the cold shield. However, this invention provides multiple heat-conducting seams 105-E on the side of the cylindrical body 105-B of the cold shield 105, such as... Figure 4 As shown, this allows the expanding gas to flow out smoothly without damaging the cold screen 105.

[0051] In one possible embodiment, both the first superconducting power source 111 and the second superconducting power source are electrically connected to the superconducting coil 102 via a circuit breaker 114.

[0052] For example, the first superconducting power supply 111 and the second superconducting power supply 112 are respectively connected to a circuit breaker 114. By controlling the opening and closing of the circuit breaker 114, the connection status of the superconducting power supply can be switched, thereby realizing the adjustment of the magnetic field uniformity.

[0053] In one possible embodiment, a support base 110 is provided on the bottom side of the vacuum Dewar inner cylinder 106.

[0054] For example, the support base 110 can be fixedly or detachably connected to the bottom of the vacuum Dewar inner cylinder 106.

[0055] This invention also provides a simulation device for plasma confinement, which includes an ion source 2, a test sample 3, and a superconducting magnet 1 for plasma confinement as described above. The ion source 2 is positioned directly opposite the test sample 3, and the ion source 2 and the test sample 3 are arranged inside the superconducting magnet 1 along the axial direction of the superconducting magnet 1.

[0056] For example, such as Figure 7 As shown, a vacuum chamber is arranged axially inside the superconducting magnet 1, and the ion source 2 and the test sample 3 are placed in the vacuum chamber. The axis of the vacuum chamber coincides with the axis of the superconducting magnet 1, and the position of the ion source 2 in the superconducting magnet 1 can be adjusted as needed.

[0057] The working process of the simulation device in this invention is as follows: Figure 10 As shown, after the superconducting magnet 1, ion source 2, and test sample 3 are installed, the vacuum unit is first used to evacuate the inside of the vacuum Dewar inner cylinder 106. When the vacuum level reaches 10... - 2 When the temperature is in the Pa range, the refrigerator 101 is turned on to cool the superconducting magnet 1, and a temperature sensor is used to monitor the temperature at important temperature detection points. When the temperature of the superconducting coil 102 inside the superconducting magnet 1 is lower than the critical temperature Tc of the superconducting wire, the superconducting coil 102 enters the superconducting state and has the ability to be energized.

[0058] Simultaneously, the vacuum chamber between ion source 2 and test sample 3 is evacuated, and after other conditions are met, in the absence of a magnetic field, if gas is introduced into ion source 2, it can be observed that the plasma, lacking confinement, rapidly disperses and cannot effectively reach test sample 3. Figure 8 As shown, the plasma density required for the experiment could not be achieved.

[0059] Therefore, firstly, based on the theoretically calculated magnetic field strength requirements for plasma confinement, the circuit breaker DCCB1 is closed, and the first superconducting power supply 111 is used to power the entire superconducting magnet 1, including the intermediate coil COIL1 and the end coils COIL2 and COIL3. Once the current in the superconducting magnet 1 reaches the set value, plasma is generated using the ion source 2. Relevant parameters of the plasma reaching the sample are measured using related testing sensors. If the magnetic field strength needs adjustment, it can be adjusted using only the first superconducting power supply 111, or the uniformity of the magnetic field distribution can be adjusted using the second superconducting power supply 112 by closing the circuit breaker DCCB2 to meet the plasma confinement requirements until the plasma confinement requirements for different working fluids are met. Figure 9 As shown. The performance tests of the relevant materials under plasma confinement were finally completed.

[0060] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0061] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A superconducting magnet for plasma confinement, characterized in that, include: A frame (103) is provided, on which a superconducting coil (102) is disposed. The superconducting coil (102) includes a middle coil and end coils. The two end coils are respectively disposed at the two ends of the frame (103), and the middle coil is disposed between the two end coils. The winding thickness of the end coils on the frame (103) is greater than the winding thickness of the middle coils on the frame (103). A cooling medium tank (104), a cold shield (105), and a cooling plate are sequentially disposed on the outside of the frame (103). Vacuum Dewar inner cylinder (106); the skeleton (103), the cooling medium tank (104), the cold screen (105) and the vacuum Dewar inner cylinder (106) are all annular cylindrical structures, and the diameters of the skeleton (103), the cooling medium tank (104), the cold screen (105) and the vacuum Dewar inner cylinder (106) increase sequentially, so that they are nested in sequence; the cooling medium tank (104) is used to hold liquid cooling medium so that the superconducting coil (102) is always below its superconducting critical temperature; The superconducting power supply includes a first superconducting power supply (111) and a second superconducting power supply (112). The first superconducting power supply (111) supplies power to the middle coil and the end coil simultaneously, and the second superconducting power supply (112) supplies power to the end coil when needed. A protection diode (113) is connected in parallel across the two ends of the middle coil and the two ends of the end coil. The protection diode (113) consists of two diodes connected in reverse parallel. A radial lifting rod (109) is provided on the outside of the frame (103). The radial lifting rod (109) passes through the cooling medium tank (104), the cold screen (105) and the vacuum Dewar inner cylinder (106), and extends out of the vacuum Dewar inner cylinder (106). An axial lifting rod (108) is parallel to the axis of the frame (103). The axial lifting rod (108) passes through the cooling medium tank (104), the cold screen (105) and the vacuum Dewar inner cylinder (106), and extends outside the vacuum Dewar inner cylinder (106).

2. A superconducting magnet for plasma confinement according to claim 1, characterized in that, A refrigerator (101) is provided on the outer surface of the vacuum Dewar inner cylinder (106), and the cold head of the refrigerator (101) is in contact with the superconducting coil (102) through the condenser (101-C).

3. A superconducting magnet for plasma confinement according to claim 2, characterized in that, The cold head of the refrigerator (101) includes a primary cold head (101-A) and a secondary cold head (101-B). The secondary cold head (101-B) is in contact with the superconducting coil (102) through the condenser (101-C), and the primary cold head (101-A) is in contact with the cold screen (105).

4. A superconducting magnet for plasma confinement according to claim 3, characterized in that, The cold screen (105) includes: Cylinder (105-B); A protruding structure (105-A) is provided on the outer side of the cylinder (105-B). A connecting hole (105-D) is provided on the protruding structure (105-A). The first-stage cold head (101-A) is inserted into the connecting hole (105-D) and contacts the protruding structure (105-A). The first-stage cold head (101-A) also passes through the connecting hole (105-D) and connects to the second-stage cold head (101-B).

5. A superconducting magnet for plasma confinement according to claim 4, characterized in that, The cylindrical body (105-B) is provided with multiple through heat-conducting slits (105-E).

6. A superconducting magnet for plasma confinement according to claim 1, characterized in that, The first superconducting power source (111) and the second superconducting power source (112) are both electrically connected to the superconducting coil (102) through a circuit breaker (114).

7. A superconducting magnet for plasma confinement according to claim 1, characterized in that, The superconducting coil (102) is electrically connected to the current lead (107), which passes through the cooling medium tank (104), the cold screen (105), and the vacuum Dewar inner cylinder (106) before being electrically connected to the superconducting power supply.

8. A superconducting magnet for plasma confinement according to claim 1, characterized in that, A support base (110) is provided on the bottom side of the vacuum Dewar inner cylinder (106).

9. A simulation device for plasma confinement, characterized in that, The device includes an ion source (2), a test sample (3), and a superconducting magnet (1) for plasma confinement as described in any one of claims 1-8. The ion source (2) is positioned opposite the test sample (3), and the ion source (2) and the test sample (3) are positioned inside the superconducting magnet (1) along the axial direction of the superconducting magnet (1).

10. A simulation device for plasma confinement according to claim 9, characterized in that, The superconducting magnet (1) has a vacuum cavity arranged along the axial direction inside, and the ion source (2) and the test sample (3) are arranged in the vacuum cavity.

Images