CN118737616B - Single-turn coil type destructive pulse magnet adopting eddy current shimming - Google Patents
Single-turn coil type destructive pulse magnet adopting eddy current shimming Download PDFInfo
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- CN118737616B CN118737616B CN202410909449.3A CN202410909449A CN118737616B CN 118737616 B CN118737616 B CN 118737616B CN 202410909449 A CN202410909449 A CN 202410909449A CN 118737616 B CN118737616 B CN 118737616B
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- eddy current
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- 230000001066 destructive effect Effects 0.000 title claims abstract description 11
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 5
- 239000004927 clay Substances 0.000 claims description 5
- 229910052802 copper Inorganic materials 0.000 claims description 5
- 239000010949 copper Substances 0.000 claims description 5
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 5
- 229910052721 tungsten Inorganic materials 0.000 claims description 5
- 239000010937 tungsten Substances 0.000 claims description 5
- 229910052715 tantalum Inorganic materials 0.000 claims description 4
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 4
- 239000000463 material Substances 0.000 abstract description 6
- 230000001052 transient effect Effects 0.000 abstract description 4
- 230000002411 adverse Effects 0.000 abstract description 3
- 230000000694 effects Effects 0.000 abstract description 3
- 230000005674 electromagnetic induction Effects 0.000 abstract description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000007599 discharging Methods 0.000 description 3
- 239000004020 conductor Substances 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000004323 axial length Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002500 effect on skin Effects 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/06—Electromagnets; Actuators including electromagnets
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/06—Electromagnets; Actuators including electromagnets
- H01F7/20—Electromagnets; Actuators including electromagnets without armatures
- H01F7/202—Electromagnets for high magnetic field strength
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
The application belongs to the technical field of a pulse strong magnetic field, and particularly discloses a single-turn coil type destructive pulse magnet adopting eddy current shimming. Comprising a magnet coil with one turn arranged on the outer side and a single turn passive closing coil arranged on the inner side. The single-turn passive closed coil at the inner side of the magnet coil generates eddy current which resists the electromagnetic transient effect of the magnet coil due to electromagnetic induction, and shields the adverse effect on the magnetic field uniformity caused by the eddy current, thereby effectively improving the magnetic field uniformity. Because the single-turn passive closed coil is made of a material with lower conductivity, the eddy current is obviously smaller than the discharge current in the magnet coil, the magnetic field is not obviously weakened, the steep magnetic field gradient can be compensated, and the magnetic field gradient is controlled in a more gentle range. Meanwhile, the single-turn passive closed coil has higher modulus, so that the deformation of the single-turn passive closed coil in the radial direction during discharge can be restrained, and the test sample in the single-turn passive closed coil is ensured.
Description
Technical Field
The application belongs to the technical field of a pulse strong magnetic field, and particularly relates to a single-turn coil type destructive pulse magnet adopting eddy current shimming.
Background
A single turn coil is a destructive pulsed magnet with a discharge current of several hundred kiloamperes to several megaamperes for generating a super strong magnetic field. Because the pulse width of the discharge current is only a few microseconds, the coil receives a huge electromagnetic force, but the electromagnetic inertia is smaller than the mechanical inertia, so that the coil realizes a peak magnetic field before mechanical damage occurs.
However, for the traditional conventional single-turn coil, the magnetic field gradient in the aperture is large and the uniformity is poor because the size of the coil is only millimeter. Such magnetic field inhomogeneities can adversely affect the experiment. In addition, the shimming of the single-turn coil is not easy to realize through a conventional shimming technology applied to other similar fields, on one hand, the shimming is limited by the low-impedance requirement of a discharging circuit of the single-turn coil, the magnet coil only has one turn, and on the other hand, the current is extremely uneven in distribution on the section of the coil due to the fact that the discharging current is large in amplitude and small in pulse width, the conductor impact deformation and the electromagnetic transient effect are obvious during discharging. The two characteristics make the single-turn coil unable to improve the magnetic field uniformity by increasing the number of turns of the coil and reasonably arranging the positions of the multiple coils or optimizing the current density distribution on the section of the coil.
Disclosure of Invention
Aiming at the defects of the prior art, the application aims to provide a single-turn coil type destructive pulse magnet adopting eddy current shimming, and aims to solve the problem of poor magnetic field uniformity of the traditional single-turn coil type magnetic body.
In order to achieve the aim, the application provides a single-turn coil type destructive pulse magnet adopting eddy current shimming, which comprises a discharge electrode plate, a magnet coil, a single-turn passive closed coil and an insulating layer;
the discharge electrode plate comprises two metal plates which are arranged in parallel, are parallel to the axial section of the magnet coil and are arranged on the radial outer side of the magnet coil;
the magnet coil has only one turn, and two ends of the magnet coil are welded on the outer surfaces of the two metal plates;
The axial height of the single-turn passive closed coil is smaller than that of the magnet coil, the single-turn passive closed coil is coaxially arranged at the inner side of the magnet coil, and an insulating layer is filled between the single-turn passive closed coil and the magnet coil;
the single turn passive closed coil has a conductivity less than the conductivity of the magnet coil and a modulus and strength greater than the modulus and strength of the magnet coil.
Preferably, the electrical conductivity of the single turn passive closed coil is less than 1 order of magnitude less than the electrical conductivity of the magnet coil.
Preferably, the material of the magnet coil is copper, and the material of the single-turn passive closed coil is tungsten or tantalum.
Preferably, the outer diameter of the single-turn passive closed coil is 0.5 mm-2.0 mm smaller than the inner diameter of the magnet coil.
Preferably, the axial height of the single-turn passive closing coil is 1.0 mm-5.0 mm smaller than the height of the magnet coil.
Preferably, the thickness of the single turn passive closing coil is less than 1mm.
Preferably, the insulating layer is resistant to temperatures above thousand ℃.
Preferably, the insulating layer is insulating clay.
Preferably, the axial height of the single turn passive closing coil is greater than the radial thickness of the single turn passive closing coil.
Preferably, the upper and lower surfaces of the single turn passive closing coil are equal from the upper and lower surfaces of the magnet coil.
In general, the above technical solutions conceived by the present application have the following beneficial effects compared with the prior art:
The application provides a single-turn coil type destructive pulse magnet adopting eddy current shimming, which comprises a magnet coil arranged on the outer side and a single-turn passive closed coil arranged on the inner side. When the pulse capacitor bank power supply discharges, a large current flows through the magnet coil, and a super strong magnetic field is generated. At the moment, although the impact deformation of the magnet coil is obvious and the electromagnetic transient effect is severe, the single-turn passive closed coil at the inner side of the magnet coil can generate eddy current which resists the electromagnetic transient effect of the magnet coil due to electromagnetic induction, and the adverse effect on the magnetic field uniformity caused by the eddy current is shielded, so that the magnetic field uniformity is effectively improved. Because the single-turn passive closed coil is made of a material with lower conductivity, the eddy current is obviously smaller than the discharge current in the magnet coil, the magnetic field is not obviously weakened, the steep magnetic field gradient can be compensated, and the magnetic field gradient is controlled in a more gentle range. Meanwhile, the single-turn passive closed coil has higher modulus, so that the deformation of the single-turn passive closed coil in the radial direction during discharge can be restrained, and the test sample in the single-turn passive closed coil can be ensured. The application can obviously increase the uniformity of the magnetic field under the condition of reducing the magnetic field at the central point less, and effectively improves the space volume with uniform magnetic field in the aperture.
Drawings
Fig. 1 is a schematic diagram of a single turn coil type destructive pulse magnet structure employing eddy current shimming according to an embodiment of the present application.
Fig. 2 is a schematic diagram showing the comparison of magnetic field uniformity of a conventional single-turn coil and a passive closed coil using a single turn coil according to an embodiment of the present application.
Detailed Description
For convenience of understanding, the following explains and describes english abbreviations and related technical terms related to the embodiments of the application.
Embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.
As shown in fig. 1, the present application provides a single-turn coil type destructive pulse magnet employing eddy current shimming, comprising a discharge electrode plate, a magnet coil, a single-turn passive closing coil, and an insulating layer (not shown);
the discharge electrode plate comprises two metal plates which are arranged in parallel, are parallel to the axial section of the magnet coil and are arranged on the radial outer side of the magnet coil;
the magnet coil has only one turn, and two ends of the magnet coil are welded on the outer surfaces of the two metal plates;
The axial height of the single-turn passive closed coil is smaller than that of the magnet coil, the single-turn passive closed coil is coaxially arranged at the inner side of the magnet coil, and an insulating layer is filled between the single-turn passive closed coil and the magnet coil;
the single turn passive closed coil has a conductivity less than the conductivity of the magnet coil and a modulus and strength greater than the modulus and strength of the magnet coil.
The direction of the eddy current generated by electromagnetic induction is the circumferential direction and is opposite to the direction of the discharge current. The insulating layer is used to prevent breakdown of the two coils.
Preferably, the electrical conductivity of the single turn passive closed coil is less than 1 order of magnitude less than the electrical conductivity of the magnet coil.
Preferably, the material of the magnet coil is copper, and the material of the single-turn passive closed coil is tungsten or tantalum.
It should be noted that the magnet coil is made of copper with high conductivity, which is beneficial to reducing the coil resistance and increasing the discharge current, and the eddy current shimming coil is made of tungsten/tantalum with high density, high modulus and low conductivity, which is beneficial to controlling the eddy current in a reasonable range and preventing the eddy current from moving at a high speed along the radial inward direction and damaging the test sample. In addition, the density and modulus of the vortex shimming coil cannot be too low, otherwise, obvious radial inward high-speed movement of the vortex shimming coil during discharge can be generated due to Lenz's law so as to destroy an internal experimental sample.
Preferably, the outer diameter of the single-turn passive closed coil is 0.5 mm-2.0 mm smaller than the inner diameter of the magnet coil.
Preferably, the axial height of the single-turn passive closing coil is 1.0 mm-5.0 mm smaller than the height of the magnet coil.
It should be noted that the inner and outer diameters of the eddy current shim coil cannot be too small, otherwise the volume of the test sample inside the single-turn coil magnet is limited, and the inner and outer diameters of the eddy current shim coil cannot be too large, otherwise the eddy current shim coil is too close to the magnet coil, so that the thickness of clay between the eddy current shim coil and the magnet coil is too thin, and the electrical insulation between the eddy current shim coil and the magnet coil is not facilitated.
Preferably, the thickness of the single turn passive closing coil is less than 1mm.
Preferably, the insulating layer is resistant to temperatures above thousand ℃.
Preferably, the insulating layer is an insulating clay, which generally has a high resistance.
Preferably, the axial height of the single turn passive closing coil is greater than the radial thickness of the single turn passive closing coil.
It should be noted that the above design is preferable in the present application to avoid the excessive axial length of the eddy current shimming coil, so as to excessively shield the magnetic field generated by the magnet coil, and cause the obvious decrease of the magnetic field intensity at the center point.
Preferably, the upper and lower surfaces of the single turn passive closing coil are equal from the upper and lower surfaces of the magnet coil, i.e. the central sections of the two are coincident with each other.
Preferably, the magnet coil axial height is equal to the magnet coil radial thickness.
Since the discharge time is short, the current is concentrated at the upper and lower edges of the inner surface of the magnet coil due to the skin effect in the cross section of the magnet coil. The magnet coils are designed so that the distribution of current is closer to an equivalent Helmholtz coil, and therefore the shimming effect is improved.
Examples
In this embodiment, the diameters (including the inner diameter, the outer diameter) of the magnet coils and the eddy current shim coils are several millimeters. The coil of the magnet has only one turn, is perpendicular to the two electrode plates, and is made of copper, and the eddy current shimming coil is coaxial with the coil of the magnet, is perpendicular to the two electrode plates, is a turn of closed conductor and is made of tungsten. An insulating clay is arranged between the two coils. The axial height and the radial thickness of the magnet coil are 3.0mm, and the axial height and the radial thickness of the eddy current shimming coil are 2.2mm and 0.3mm respectively.
As shown in FIG. 2, under the conditions of 300kA of discharge peak current, 1.4 mu s of current peak time, 6.0mm of magnet inner diameter and 4.6mm of eddy current shimming coil outer diameter, the magnetic field uniformity of the traditional single-turn coil magnet and the shimming single-turn coil magnet is shown schematically at 1.4 mu s, and the magnetic field uniformity of the shimming single-turn coil magnet is effectively improved compared with that of the traditional single-turn coil magnet under the condition of identical discharge current curve, and the shimming space volume is increased to 10-25 times under the condition of different magnetic field uniformity. Meanwhile, at 1.4 microseconds, the magnet coil has obvious impact deformation under the action of electromagnetic force, and the deformation of the eddy current shimming coil is not obvious.
It is to be understood that the terms such as "comprises" and "comprising," which may be used in this application, indicate the presence of the disclosed functions, operations or elements, and are not limited to one or more additional functions, operations or elements. In the present application, terms such as "comprising" and/or "having" may be construed to mean a particular feature, number, operation, constituent element, component, or combination thereof, but may not be construed to exclude the presence or addition of one or more other features, numbers, operations, constituent elements, components, or combination thereof.
Furthermore, in the present application, the expression "and/or" includes any and all combinations of the words listed in association. For example, the expression "a and/or B" may include a, may include B, or may include both a and B.
In describing embodiments of the present application, it should be noted that the term "coupled" should be interpreted broadly, unless explicitly stated or limited otherwise, and for example, the term "coupled" may be either detachably coupled or non-detachably coupled, or may be directly coupled or indirectly coupled via an intermediate medium. Wherein, "fixedly connected" means that the relative positional relationship is unchanged after being connected with each other. "rotationally coupled" means coupled to each other and capable of relative rotation after coupling. "slidingly coupled" means coupled to each other and capable of sliding relative to each other after being coupled. References to directional terms in the embodiments of the present application, such as "top", "bottom", "inner", "outer", "left", "right", etc., are merely with reference to the directions of the drawings, and thus are used in order to better and more clearly illustrate and understand the embodiments of the present application, rather than to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the embodiments of the present application.
In addition, in embodiments of the present application, the mathematical concepts mentioned are symmetrical, equal, parallel, perpendicular, etc. These definitions are all for the state of the art and not strictly defined in a mathematical sense, allowing for minor deviations, approximately symmetrical, approximately equal, approximately parallel, approximately perpendicular, etc. For example, a is parallel to B, meaning that a is parallel or approximately parallel to B, and the angle between a and B may be between 0 degrees and 10 degrees. A and B are perpendicular, which means that the angle between A and B is between 80 degrees and 100 degrees.
The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (9)
1. A single-turn coil type destructive pulse magnet adopting eddy current shimming is characterized by comprising a discharge electrode plate, a magnet coil, a single-turn passive closed coil and an insulating layer;
the discharge electrode plate comprises two metal plates which are arranged in parallel, are parallel to the axial section of the magnet coil and are arranged on the radial outer side of the magnet coil;
the magnet coil has only one turn, and two ends of the magnet coil are welded on the outer surfaces of the two metal plates;
The axial height of the single-turn passive closed coil is smaller than that of the magnet coil, the single-turn passive closed coil is coaxially arranged at the inner side of the magnet coil, and an insulating layer is filled between the single-turn passive closed coil and the magnet coil;
The conductivity of the single-turn passive closed coil is smaller than that of the magnet coil, and the modulus and the strength of the single-turn passive closed coil are larger than those of the magnet coil;
the magnet coil is made of copper, and the single-turn passive closed coil is made of tungsten or tantalum.
2. A pulsed magnet according to claim 1, characterized in that the electrical conductivity of the single turn passive closed coil is less than 1 order of magnitude less than the electrical conductivity of the magnet coil.
3. A pulsed magnet according to claim 1, wherein the outer diameter of the single turn passive closed coil is 0.5mm to 2.0mm smaller than the inner diameter of the magnet coil.
4. A pulsed magnet according to claim 1, wherein the axial height of the single turn passive closed coil is 1.0mm to 5.0mm less than the height of the magnet coil.
5. A pulsed magnet according to claim 1, wherein the thickness of the single turn passive closing coil is less than 1mm.
6. The pulse magnet of claim 1, wherein the insulating layer is resistant to temperatures above thousand degrees celsius.
7. The pulse magnet of claim 6, wherein the insulating layer is an insulating clay.
8. A pulse magnet as defined in claim 1, wherein the axial height of the single turn passive closing coil is greater than the radial thickness of the single turn passive closing coil.
9. A pulse magnet as defined in any one of claims 1 to 8, wherein the upper and lower surfaces of the single turn passive closing coil are equidistant from the upper and lower surfaces of the magnet coil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410909449.3A CN118737616B (en) | 2024-07-08 | 2024-07-08 | Single-turn coil type destructive pulse magnet adopting eddy current shimming |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202410909449.3A CN118737616B (en) | 2024-07-08 | 2024-07-08 | Single-turn coil type destructive pulse magnet adopting eddy current shimming |
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| Publication Number | Publication Date |
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| CN118737616A CN118737616A (en) | 2024-10-01 |
| CN118737616B true CN118737616B (en) | 2024-12-31 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105170767A (en) * | 2015-10-13 | 2015-12-23 | 福州大学 | Device and method for forming metal sheet through electromagnetic attraction force |
| CN111133326A (en) * | 2017-09-28 | 2020-05-08 | 西达-赛奈医疗中心 | Magnetic resonance coils for simultaneous imaging and B0 shimming |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0963400A1 (en) * | 1997-02-28 | 1999-12-15 | JOHNSON, Robert Harlan Jr. | High efficiency heating agents |
| CN113325351B (en) * | 2021-05-06 | 2022-04-08 | 华中科技大学 | Device and method for generating high uniformity pulsed strong magnetic field |
| WO2022256077A1 (en) * | 2021-06-01 | 2022-12-08 | Helion Energy, Inc. | Monolithic high field magnets for plasma target compression |
| CN114609534B (en) * | 2022-01-21 | 2025-05-02 | 三一技术装备有限公司 | A cell resistance measuring device, a measuring method and an OCV testing device |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105170767A (en) * | 2015-10-13 | 2015-12-23 | 福州大学 | Device and method for forming metal sheet through electromagnetic attraction force |
| CN111133326A (en) * | 2017-09-28 | 2020-05-08 | 西达-赛奈医疗中心 | Magnetic resonance coils for simultaneous imaging and B0 shimming |
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