Magnetic probe calibration device and calibration method for magnetic confinement fusion

Abstract

The invention discloses a magnetic probe calibration device and a calibration method for magnetic confinement fusion, and relates to the technical field of magnetic probe calibration, the calibration device comprises a standard probe, the standard probe comprises a cylindrical skeleton with a known outer diameter and a winding wire, the winding wire is wound on the outer wall of the cylindrical skeleton, the number of turns of the winding wire is known, and the outer diameter of the winding wire is known; signal output ends of the standard probe are formed at two ends of the winding wire; a power supply wire wound outside the long straight solenoid is connected with a power supply; part of the outer wall of the calibration bearing body is matched with the inner wall of the long straight solenoid, and a bearing surface for placing a standard probe is formed on the outer wall of the calibration bearing body far away from the outer wall abutting against the inner wall of the long straight solenoid; errors caused by a magnetic field generating device (a long straight solenoid, a constant ferromagnet and the like) can be eliminated, energizing current for generating the magnetic field does not need to be measured, the introduced error sources are reduced, the method has the advantages of being convenient and rapid to operate, high in calibration precision, good in repeatability and the like, and the effective area of the magnetic probe is accurately calibrated.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic probe calibration, and more specifically, to a magnetic probe calibration device and a calibration method for magnetic confinement fusion. Background Art

[0002] In devices operating in the field of magnetic confinement, such as tokamaks, stellarators, linear devices and magnetic mirrors, it is necessary to measure magnetic signals (magnetic flux, magnetic field, magnetic rate of change, etc.) for monitoring important parameters of the device, operation control and physical research. The accurate measurement of these signals is very important. Among them, the most commonly used is a pickup coil based on electromagnetic induction. The pickup coil is a single-turn or multi-turn coil wound with a winding wire. When the magnetic flux it surrounds changes, an induced electromotive force will be generated at both ends of the pickup coil. If the pickup coil is made small enough so that the magnetic field passing through the pickup coil can be considered uniform, it is generally called a magnetic probe in the field of magnetic confinement, which can be expressed as: In the formula, n is the number of turns (turn), and A is the area (area) enclosed by a single turn of the magnetic probe. Since the area A of each turn of the magnetic probe is not strictly equal, nA is generally used as a whole to represent the effective area of ​​the magnetic probe. B represents the magnetic induction intensity that passes vertically through the magnetic probe. The voltage ξ(t) induced at both ends of the magnetic probe coil is integrated over time, such as by using an analog signal integrator to integrate, and the magnetic field B(t) at the location of the magnetic probe can be obtained. Therefore, accurately calibrating the effective area (nA value) of the magnetic probe is an important factor in achieving accurate measurement of the magnetic field by the magnetic probe.

[0003] The traditional methods for calibrating the nA value of magnetic probes are as follows:

[0004] 1. Probe circle rotation method: Place the magnetic probe in a static magnetic field of known size, such as a permanent magnet, and use a motor rotor with a known angular frequency to rotate the magnetic probe at a constant speed. The induced voltage at both ends of the magnetic probe is led out to an analog-to-digital signal converter (or data acquisition device), oscilloscope or digital multimeter through a brush to measure the induced voltage. The actual calibration is as follows: Figure 1 As shown, the voltage ξ(t) induced at both ends can be expressed as: B0 is the static magnetic field amplitude at the location of the magnetic probe. Due to the uniform rotation, the induced voltage is a sinusoidal waveform. The rotor angular velocity is ω, which can be expressed as: The amplitudes of sine and cosine are equal, and the phase difference is 90 degrees. The nA value to be measured can be simplified as: Therefore, as long as the ξ, ω, and B0 values ​​are obtained, the nA value can be obtained; this method has the following disadvantages or problems:

[0005] ①. The magnetic probe needs to be rotated by a motor, which makes the operation more complicated. In addition, the signal needs to be led out by a brush or other mechanism, which will bring a certain stray area ΔnA and affect the accuracy of the nA value.

[0006] ② If the rotation is eccentric or the uniformity of the rotation angular frequency ω is poor, it will lead to unstable ξ and ω values, and the accuracy of nA calibration will be difficult to guarantee.

[0007] ③. The magnetic field generated by the permanent magnet still needs to be measured using other magnetic field measurement methods, such as a Gaussmeter.

[0008] In summary, the probe rotation method introduces many variables and unstable factors, and it is difficult to improve the calibration accuracy of the nA value.

[0009] 2. Solenoid coil energization method: Use a long straight solenoid or Helmholtz coil to generate a magnetic field (AC or DC) for calibration. Since the uniformity of the long straight solenoid is better than that of the Helmholtz coil, the relationship between the magnetic field amplitude B and the energized current I at the center of the long straight solenoid is obtained by calculating the energized current, turn density, geometric dimensions, etc. of the long straight solenoid: B(t) = μnI(t), μ is the magnetic permeability, and for a solenoid made of non-magnetic material, the vacuum magnetic permeability μ0 = 4π×10 -7 N.A -2 , n is the turn density of the solenoid, the unit is turns / meter, I is the current, the unit is ampere; this method, by measuring the current I, can calculate the magnetic field size at the center of the solenoid, when the magnetic field size is known, the nA value of the magnetic probe can be calibrated.

[0010] If a DC pulse magnetic field is used, the magnetic probe signal needs to be integrated to obtain the nA value: B is the magnetic field at the center of the solenoid calculated by the current I, U is the integrator output voltage, and RC is the integrator time constant.

[0011] If a sinusoidal AC magnetic field is used, then: B0 is the magnetic field value calculated by the alternating current I, ω is the angular frequency of the alternating current, and ξ is the induced voltage at both ends of the magnetic probe.

[0012] The disadvantages of this method are:

[0013] ①. Long straight solenoids have errors caused by processing and winding, that is, the formula B(t) = μnI(t) has unpredictable differences from the actual production. The impact of this error is more difficult to estimate than the production deviation of the "standard probe", and there are major problems in practical applications.

[0014] ② The magnetic field needs to be obtained by measuring the current of the solenoid coil. The measurement accuracy of the current directly affects the calibration accuracy of the nA value.

[0015] ③. If a DC pulse magnetic field is used, the deviation of the integrator RC needs to be introduced, which reduces the accuracy.

[0016] In view of this, this patent application is filed to improve the calibration accuracy of the nA value of the magnetic probe. Summary of the invention

[0017] The purpose of the present invention is to provide a magnetic probe calibration device and calibration method for magnetic confinement fusion, which can eliminate the error brought by the magnetic field generating device (long straight solenoid, constant ferromagnet, etc.) itself, and there is no need to measure the current passing through the magnetic field to generate the magnetic field, so the source of error introduced is reduced. It has the advantages of convenient and fast operation, high calibration accuracy, good repeatability, etc., and can realize accurate calibration of the effective area (nA value) of the magnetic probe.

[0018] The above technical objectives of the present invention are achieved through the following technical solutions:

[0019] In a first aspect, the present application provides a magnetic probe calibration device for magnetic confinement fusion, comprising:

[0020] A standard probe, the standard probe comprises a cylindrical frame with a known outer diameter, and a winding wire with a known number of turns and a known outer diameter wound around the outer wall of the cylindrical frame, and two ends of the winding wire form signal output ends of the standard probe;

[0021] A long straight solenoid, wherein the power supply wire wound around the outer wall of the long straight solenoid is connected to a power supply;

[0022] A calibration carrier, the outer wall of the calibration carrier is adapted to the inner wall of the long straight solenoid, the outer wall of the calibration carrier away from the inner wall of the long straight solenoid forms a bearing surface for placing the standard probe, when the calibration carrier is sent into the interior of the long straight solenoid, the standard probe is on the central axis of the long straight solenoid and parallel to it.

[0023] The beneficial effects of the present invention are as follows: in the present scheme, the standard probe is a probe coil with a winding wire wound on a cylindrical frame, and the frame can be made of alumina ceramic material to reduce the change in cross-sectional area A caused by thermal expansion and contraction caused by temperature changes; the outer wall of the long straight solenoid is also wound with a wire, and the two ends of the wire are connected to a power supply to generate a magnetic field; the function of the calibration carrier is to carry the standard probe and to deliver the standard probe into the interior of the long straight solenoid so that the standard probe is located at the exact center of the magnetic field generated in the long straight solenoid.

[0024] In this scheme, the calibration deviation caused by the long straight solenoid can be reduced as much as possible, and a method that is almost independent of the long straight solenoid itself is adopted, in which only a "standard probe" with extremely high precision needs to be made to relatively calibrate the effective area nA value of the magnetic probe under test; in this way, the problem of low calibration accuracy caused by the manufacturing process of the long straight solenoid can be avoided, and there is no need to measure the current of the long straight solenoid, so that the calibration accuracy is not affected by the magnetic field generating equipment (such as the long straight solenoid) itself, but is mainly related to the "standard probe".

[0025] Based on the above technical solution, the present invention can also be improved as follows.

[0026] Furthermore, the bearing surface is provided with a probe groove for placing a standard probe.

[0027] The beneficial effect of adopting the above further solution is that the standard probe can be placed to avoid shaking of the standard probe.

[0028] Furthermore, the inner diameter of the long straight solenoid is not less than 3 times the outer diameter of the standard probe or the probe to be tested.

[0029] Furthermore, the length of the long straight solenoid is not less than 6 times the length of the standard probe or the probe to be tested.

[0030] The beneficial effects of adopting the above further solution are: reducing the difficulty of manufacturing the long straight solenoid and ensuring that the standard probe and the magnetic probe to be measured are in a magnetic field with high uniformity.

[0031] Furthermore, the material of the cylindrical skeleton is alumina ceramics.

[0032] The beneficial effect of adopting the above further solution is to reduce the change in cross-sectional area caused by thermal expansion and contraction due to temperature changes.

[0033] Furthermore, the side surface of the calibration carrier in the radial direction is a semicircular fan-shaped structure.

[0034] The beneficial effects of adopting the above further solution are: achieving better fit with the inner wall of the long straight solenoid and delivering the standard probe straightly into the center of the solenoid.

[0035] In a second aspect, the present application provides a method for calibrating a magnetic probe for magnetic confinement fusion, which is applied to a magnetic probe calibration device for magnetic confinement fusion in any one of the first aspects, and includes the following specific steps:

[0036] Connect the two ends of the power supply wire on the outer wall of the long straight solenoid to the power supply;

[0037] Placing the standard probe on the bearing surface of the calibration bearing body, and feeding the standard probe into the long straight solenoid through the calibration bearing body;

[0038] Use a digital multimeter to connect the signal output terminal of the standard probe and read the voltage value 1 generated by the standard probe under the alternating magnetic field;

[0039] The standard probe is withdrawn through the calibration carrier, and the probe to be tested is sent into the long straight solenoid through the calibration carrier, and the position to which the standard probe is sent is the same as the position to which the probe to be tested is sent;

[0040] Use a digital multimeter to connect the signal output terminal of the probe to be tested, and read the voltage value 2 generated by the probe to be tested under the alternating magnetic field;

[0041] The target effective area of ​​the probe to be tested is calculated using the voltage value 1 and the voltage value 2 based on the standard effective area of ​​the standard probe.

[0042] Furthermore, the standard effective area of ​​the above standard probe is specifically:

[0043]

[0044] Wherein, (nA)0 represents the standard effective area of ​​the standard probe, n0 represents the known number of turns of the winding wire, D represents the outer diameter of the cylindrical frame, δD represents the outer diameter tolerance of the cylindrical frame, d represents the outer diameter of the winding wire, and δd represents the outer diameter tolerance of the winding wire.

[0045] Furthermore, the target effective area of ​​the above-mentioned probe to be tested is specifically:

[0046]

[0047] Wherein, nA represents the target effective area of ​​the probe to be tested, ξ represents the voltage value 2 generated by the probe to be tested under the alternating magnetic field, ξ0 represents the voltage value 1 generated by the standard probe under the alternating magnetic field, and (nA)0 represents the standard effective area of ​​the standard probe.

[0048] In a third aspect, the present application provides a use of a magnetic probe calibration device for magnetic confinement fusion as described in any one of the first aspects in calibrating the effective area of ​​a magnetic probe.

[0049] Compared with the prior art, the present invention has at least the following beneficial effects:

[0050] In the present application, the standard probe is a probe coil with a winding wire wound on a cylindrical frame. The frame can be made of alumina ceramic material to reduce the change in cross-sectional area A caused by thermal expansion and contraction due to temperature changes; the outer wall of the long straight solenoid is also wound with a wire, and the two ends of the wire are connected to a power supply to generate an alternating magnetic field; the function of the calibration carrier is to carry the standard probe and to deliver the standard probe into the interior of the long straight solenoid so that the standard probe is located at the exact center of the magnetic field generated in the long straight solenoid.

[0051] In the present application, the calibration deviation caused by the long straight solenoid can be reduced as much as possible, and a method that is almost independent of the long straight solenoid itself is adopted, in which only a "standard probe" with extremely high precision needs to be manufactured to relatively calibrate the effective area nA value of the magnetic probe being measured; in this way, the problem of low calibration accuracy caused by the manufacturing process of the long straight solenoid can be avoided, and there is no need to measure the current of the long straight solenoid, so that the calibration accuracy is not affected by the magnetic field generating equipment (such as the long straight solenoid) itself, but is almost only related to the "standard probe".

[0052] In the present application, the probe groove is used to place the standard probe to prevent the standard probe from shaking; the length of the long straight solenoid is not less than 6 times the length of the standard probe or the probe to be tested, which reduces the difficulty of manufacturing the long straight solenoid and can ensure that the standard probe and the magnetic probe to be tested are in a magnetic field with higher uniformity; the material of the cylindrical skeleton is alumina ceramic to reduce the change in cross-sectional area caused by thermal expansion and contraction due to temperature changes; the side of the calibration carrier in the radial direction is a semicircular fan-shaped structure to achieve a better fit with the inner wall of the long straight solenoid, and the standard probe is sent straight into the center of the solenoid. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0054] Figure 1 This is a schematic diagram of the structure of a standard probe in an embodiment of the present invention;

[0055] Figure 2 It is a schematic diagram of the standard probe, the long straight solenoid, and the calibration carrier in an embodiment of the present invention;

[0056] Figure 3 Schematic diagram of the introduction of a standard probe or a probe to be tested in an embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0058] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0060] In the description of the embodiments of the present invention, it should be noted that if the terms "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when used. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0061] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0062] In the description of the embodiments of the present invention, "plurality" means at least 2.

[0063] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] Embodiment 1: In order to eliminate the error caused by the magnetic field generating device (long straight solenoid, constant ferromagnet, etc.), when there is no need to measure the current that generates the magnetic field, the error source introduced is reduced, and in order to achieve the purposes of convenient and fast operation, high calibration accuracy, good repeatability, etc., to accurately calibrate the effective area (nA value) of the magnetic probe, this embodiment provides a magnetic probe calibration device for magnetic confinement fusion, such as Figure 1-Figure 3 As shown, including:

[0065] A standard probe includes a cylindrical frame with a known outer diameter, and a winding wire with a known number of turns and a known outer diameter wound around the outer wall of the cylindrical frame, and both ends of the winding wire form signal output ends of the standard probe; Figure 1 As shown, the material of the cylindrical skeleton is alumina ceramic.

[0066] Furthermore, the calibration device further comprises: a long straight solenoid, a power supply wire wound around the outer wall of the long straight solenoid is connected to a power supply, such as Figure 2 and Figure 3 shown.

[0067] Optionally, the inner diameter of the long straight solenoid is not less than 3 times the outer diameter of the standard probe or the probe to be tested, and the length of the long straight solenoid is not less than 6 times the length of the standard probe or the probe to be tested.

[0068] Furthermore, the calibration device further comprises: a calibration carrier, the outer wall of the calibration carrier being adapted to the inner wall of the long straight solenoid, such as Figure 2 and Figure 3 As shown, the outer wall of the calibration carrier away from the inner wall of the long straight solenoid forms a bearing surface for placing the standard probe. When the calibration carrier is fed into the interior of the long straight solenoid, the standard probe is on the central axis of the long straight solenoid and parallel to it.

[0069] Optionally, the bearing surface is provided with a probe groove for placing the standard probe, so as to place the standard probe and prevent the standard probe from shaking. Figure 2 and Figure 3 As shown, the side surface of the calibration carrier in the radial direction is a semicircular fan-shaped structure.

[0070] Example 2: The embodiment of the present application provides a calibration device that can calibrate the nA value of a magnetic probe very accurately. In principle, the device is no longer dependent on the error caused by the magnetic field generating device (long straight solenoid, constant ferromagnet, etc.) itself, and does not need to measure the current that generates the magnetic field, so the error source introduced is very small; and it has the advantages of convenient and fast operation, high calibration accuracy, and good repeatability. The calibration device provided in this embodiment also adopts the method of energizing a long straight solenoid, but a "standard probe" is manufactured and used as a standard, and the relative calibration method is required to calibrate the magnetic probe; the device can achieve the technical indicators of calibration deviation not exceeding ±0.1% and stability not exceeding ±0.02%; the advantages of the above calibration device compared with other methods or devices are shown in Table 1.

[0071] Table 1 Analysis of the advantages and disadvantages of this application compared with other calibration methods or devices

[0072]

[0073] Specifically, the calibration device provided in this embodiment mainly solves the accurate calibration of the effective area nA value of the magnetic probe to improve the accuracy of the magnetic field measured by the magnetic probe on the magnetic confinement device. The calibration device can control the calibration deviation of the effective area nA value within ±0.1%, and the calibration repeatability within ±0.02%; it can greatly improve the accuracy of magnetic confinement and related fields, and the accuracy of magnetic field magnetic probe measurement, and can provide more accurate magnetic field signals for plasma control. In order to minimize the calibration deviation caused by the long straight solenoid, a method that is almost independent of the long straight solenoid itself is adopted, in which a "standard probe" with extremely high precision is required to be made for relative calibration of the effective area nA value of the measured magnetic probe. In this way, the problem of low calibration accuracy caused by the manufacturing process of the long straight solenoid can be avoided, and there is no need to measure the current of the long straight solenoid. As a result, the calibration accuracy is not affected by the magnetic field generating device (such as the long straight solenoid) itself, but is almost only related to the "standard probe". The calibration device mainly includes three aspects: making an ultra-high precision standard probe, making a long straight solenoid suitable for calibration, and using the relative calibration method for calibration.

[0074] Among them, the production of the standard probe: the "standard probe" in this embodiment is a probe coil with a winding wire wound on a cylindrical ceramic skeleton; the skeleton needs to be made of alumina ceramic material to reduce the thermal expansion and contraction caused by temperature changes, and the changes in the cross-sectional area A. The winding area of ​​the skeleton, that is, the machining error of the cylindrical surface is required not to exceed ±0.02% of the outer diameter of the skeleton itself. For example, if a ceramic skeleton with an outer diameter of 50mm is used to wind the "standard probe", its outer diameter is required to be controlled at 50±0.01mm, which can be achieved through precision machining and can be measured and verified by micrometer. The relationship between the cross-sectional area S and the outer diameter of the probe coil skeleton: Where S is the cross-sectional area of ​​the "standard probe" skeleton, D is the outer diameter, δD is the outer diameter tolerance, and the relative tolerance is δD / D.

[0075] Specifically, a ceramic cylindrical skeleton with an outer diameter tolerance not exceeding ±0.02% can be used, and a winding wire with a known outer diameter d and a tolerance δd not exceeding ±0.01% of the ceramic skeleton size (such as an enameled wire with d±δd=0.5±0.005mm) can be wound on the surface, and a known number of turns (n0 turns) can be tightly wound. The effective area (nA)0 of the "standard probe" can be expressed as:

[0076]

[0077] Where d is the wire diameter of the winding cable, δd is the wire diameter tolerance, and the “standard probe” diagram is shown in Figure 1 ; The "standard probe" made according to this method has a true value of effective area (nA)0 that can achieve an accuracy requirement better than ±0.06% compared to the theoretical value.

[0078] Among them, the long straight solenoid and power supply: the calibration device also includes a long straight solenoid and a power supply to generate a magnetic field; the diameter D of the long straight solenoid s Not less than 3 times the outer diameter D of the standard probe and the magnetic probe being measured, that is: D s ≥3D. The length of the long straight solenoid is L s It should be much larger than the length L of the "standard probe" and the magnetic probe to be measured. In this embodiment, in order to reduce the difficulty of making a long straight solenoid, L is required s Not less than 6 times of L, to ensure that the "standard probe" and the magnetic probe being tested are in a highly uniform magnetic field. s ≥6L; See the schematic diagram of the size comparison between the long straight solenoid and the "standard probe" (or the magnetic probe to be measured) for Figure 2 .

[0079] Among them, the relative calibration method: use a "standard probe" with a deviation of no more than ±0.06% to relatively calibrate the magnetic probe to be tested. The feasibility lies in that the "standard probe" and the magnetic probe to be tested are placed in the same position of the long straight solenoid (magnetic field of the same amplitude and frequency), according to the formula:

[0080]

[0081] Specifically, if the intensity B0 and frequency ω of the magnetic field in which the probe coil is located are the same, the induced voltage is proportional to the effective area of ​​the probe coil: ξ(t)∝nA; while the effective area of ​​the "standard probe" is (nA)0, and the effective area of ​​the magnetic probe to be measured is nA, the following method and steps are used for calibration:

[0082] Step 1: Use a stable alternating current source to pass a constant peak alternating current through the long straight solenoid coil, and a constant alternating magnetic field will be generated inside the solenoid.

[0083] Step 2: Send the "standard probe" to the center of the long straight solenoid through the calibration carrier, lead the signal of the "standard probe" away from the solenoid, and use a digital multimeter (with an accuracy of six and a half digits or above) to read the voltage value ξ0; Figure 3 Shown is a schematic diagram of a "standard probe" being fed into a long straight solenoid through a carrier.

[0084] Step 3: Remove the "standard probe" and replace it with the magnetic probe to be tested at the same position. The insertion method is similar to that of the "standard probe". Make the position of the magnetic probe to be tested as consistent as possible with that of the "standard probe". The position reset deviation is required to be no more than ±1mm. This is achieved by calibrating the geometric scale designed on the carrier. The signal is led out to a point far away from the solenoid, and the voltage value ξ is read using the same digital multimeter.

[0085] Step 4: Calculate the effective area of ​​the magnetic probe being measured:

[0086] In the formula, (nA)0 is the effective area of ​​the "standard probe" made with high precision, and its deviation does not exceed ±0.06%. ξ0 and ξ are the induced voltage values ​​measured by a voltmeter with a precision of six and a half digits or above; therefore, the calibration deviation of the magnetic probe nA value can be better than ±0.1%; repeat the above steps, and the repeatability of multiple calibrations mainly comes from the power-on calibration source and the position of the digital multimeter and the probe circle, and the reproducibility of the calibration can be better than ±0.02%; this calibration method, in the whole process, except for measuring the probe circle voltage, does not introduce any errors caused by other physical quantities.

[0087] Specifically, the calibration device provided in this embodiment includes a high-precision "standard probe", a long straight solenoid of a specified size and a power supply, and adopts a relative calibration method; according to the calibration device made in this embodiment, the deviation of the effective area nA value of the electromagnetic induction type magnetic probe calibrated does not exceed ±0.1%, and can achieve a repeatability better than ±0.02%. And the calibration device provided in this embodiment does not need to rotate the magnetic probe to be measured, nor does it need to introduce an integral circuit and other links at the rear end of the probe circle. It only needs to be placed in the center of the solenoid and measure the induced voltage of the probe circle, and can be calibrated independently of the error of the magnetic field generating device (such as a long straight solenoid). At the same time, the calibration device provided in this embodiment is suitable for various types of magnetic probes, and is also suitable for the test calibration of two-dimensional and three-dimensional magnetic probes; it can also be extended to the calibration of other magnetic field sensors, such as magnetic field sensors based on the Hall principle, Faraday optical rotation effect, etc., which are not suitable for probe circles that need to be rotated for measurement; it is also suitable for the calibration of pulsed constant magnetic field and alternating magnetic field related sensors, for alternating magnetic fields, generally not more than 1kHz frequency magnetic field calibration.

[0088] Embodiment 3: The embodiment of the present application provides a method for calibrating a magnetic probe for magnetic confinement fusion, which is applied to a magnetic probe calibration device for magnetic confinement fusion in any one of Embodiment 1, and includes the following specific steps:

[0089] S1, connect the two ends of the power supply wire on the outer wall of the long straight solenoid to the power supply.

[0090] S2, placing the standard probe on the bearing surface of the calibration bearing body, and sending the standard probe into the long straight solenoid through the calibration bearing body.

[0091] S3, use a digital multimeter to connect the signal output terminal of the standard probe, and read the voltage value 1 generated by the standard probe under the alternating magnetic field.

[0092] S4, withdraw the standard probe through the calibration carrier, and send the probe to be tested into the long straight solenoid through the calibration carrier, and the position to which the standard probe is sent is the same as the position to which the probe to be tested is sent.

[0093] S5, using a digital multimeter to connect the signal output terminal of the probe to be tested, and reading the voltage value 2 generated by the probe to be tested under the alternating magnetic field.

[0094] S6, using the voltage value 1 and the voltage value 2, and based on the standard effective area of ​​the standard probe, calculate the target effective area of ​​the probe to be tested.

[0095] Optionally, the standard effective area of ​​the above standard probe is specifically:

[0096]

[0097] Wherein, (nA)0 represents the standard effective area of ​​the standard probe, n0 represents the known number of turns of the winding wire, D represents the outer diameter of the cylindrical frame, δD represents the outer diameter tolerance of the cylindrical frame, d represents the outer diameter of the winding wire, and δd represents the outer diameter tolerance of the winding wire.

[0098] Optionally, the target effective area of ​​the above-mentioned probe to be tested is specifically:

[0099]

[0100] Wherein, nA represents the target effective area of ​​the probe to be tested, ξ represents the voltage value 2 generated by the probe to be tested under the alternating magnetic field, ξ0 represents the voltage value 1 generated by the standard probe under the alternating magnetic field, and (nA)0 represents the standard effective area of ​​the standard probe.

[0101] Example 4: This embodiment of the present application provides the use of a magnetic probe calibration device for magnetic confinement fusion as described in any one of Example 1 in calibrating the effective area of ​​a magnetic probe.

[0102] Specifically, the following example further illustrates that the China Tokamak-3 is currently (2024) the domestic tokamak device with the highest parameters in the field of magnetic confinement. In order to achieve high-precision magnetic field measurement for accurate control of the plasma of the HL-3 device, the magnetic probes developed are calibrated using the device in this application, and the repeatability of the calibration (multiple tests in a short period of time, and retests within a certain period of time) is within ±0.02%. Under the relative calibration of the "standard probe" with a deviation not exceeding ±0.06%, the calibration deviation of the calibrated probe does not exceed ±0.1%.

[0103] The following are examples and data:

[0104] Table 2 shows the results of the standard probe and the magnetic probes 1 and 2 to be tested, which were measured three times at 24-hour intervals; Standard probe (nA) 0 = 0.50145 ± 0.00050 m 2 .

[0105] Table 2 Results of periodic repetition of standard probe and multiple magnetic probes

[0106]

[0107] Among them, the single-day repeatability, taking the three tests of 0.29119V, 0.29118V, and 0.29118V by magnetic probe 1 on April 21, 2022 as an example, the maximum repeatability difference is:

[0108] Among them, the next-day repeatability test data is 0.291183V, 0.291047V, and the next-day repeatability is:

[0109]

[0110] Specifically, the reason for the large deviation in the repetition every other day is that the parameters of the current source have undergone non-negligible changes within a certain time period. If the current source is unstable within a period of hours, then the nA value of the magnetic probe directly calibrated is unstable; in order to eliminate the calibration deviation caused by variable factors such as the current source, the relative calibration method in this application is used to greatly reduce the problem of large repeatability deviation (±0.047%). For example: the normalized ratio of the standard probe, the measured magnetic probe 1, and the magnetic probe 2, that is: The normalized ratio of the next day is: 1.00000:0.398952:0.400231, and the normalized ratio of the next day is: 1.00000:0.398900:0.400179. The so-called normalized ratio is that the standard probe is regarded as "1", and the ratio of the measured magnetic probe is obtained according to ξ / ξ0.

[0111] Furthermore, using the relative calibration method, the repetition of the magnetic probe 1 every other day is:

[0112] Further, the magnetic probe 2 is repeated every other day as follows:

[0113] Specifically, the relative calibration method eliminates the unstable factors caused by the power supply and can achieve repeatability within 0.02%. In order to control the calibration deviation of the magnetic probe, the standard probe needs to be manufactured in strict accordance with the standard probe process requirements, that is, the effective area deviation of the standard probe does not exceed ±0.06%. Under this indicator, the effective area deviation of the measured magnetic probe can be better than ±0.1%.

[0114] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A magnetic probe calibration device for magnetic confinement fusion, characterized in that: include: A standard probe, the standard probe comprising a cylindrical frame with a known outer diameter, and a winding wire with a known number of turns and a known outer diameter wound around the outer wall of the cylindrical frame, wherein two ends of the winding wire form signal output ends of the standard probe; A long straight solenoid, wherein the power supply wire wound around the outer wall of the long straight solenoid is connected to a power supply; A calibration carrier, wherein the outer wall of the calibration carrier is adapted to the inner wall of the long straight solenoid, and the outer wall of the calibration carrier away from the inner wall of the long straight solenoid forms a bearing surface for placing a standard probe. When the calibration carrier is fed into the interior of the long straight solenoid, the standard probe is on the central axis of the long straight solenoid and parallel to it.

2. A magnetic probe calibration device for magnetic confinement fusion according to claim 1, characterized in that: The bearing surface is provided with a probe groove for placing a standard probe.

3. A magnetic probe calibration device for magnetic confinement fusion according to claim 1, characterized in that: The inner diameter of the long straight solenoid is not less than 3 times the outer diameter of the standard probe or the probe to be tested.

4. A magnetic probe calibration device for magnetic confinement fusion according to claim 1, characterized in that: The length of the long straight solenoid is not less than 6 times the length of the standard probe or the probe to be tested.

5. A magnetic probe calibration device for magnetic confinement fusion according to claim 1, characterized in that: The material of the cylindrical skeleton is alumina ceramics.

6. A magnetic probe calibration device for magnetic confinement fusion according to claim 1, characterized in that: The side surface of the calibration carrier in the radial direction is a semicircular sector-shaped structure.

7. A method for calibrating a magnetic probe for magnetic confinement fusion, applied to a device for calibrating a magnetic probe for magnetic confinement fusion according to any one of claims 1 to 6, characterized in that: The specific steps include: Connect the two ends of the power supply wire on the outer wall of the long straight solenoid to the power supply; Placing the standard probe on the bearing surface of the calibration bearing body, and feeding the standard probe into the long straight solenoid through the calibration bearing body; Use a digital multimeter to connect the signal output terminal of the standard probe and read the voltage value 1 generated by the standard probe under the alternating magnetic field; The standard probe is withdrawn through the calibration carrier, and the probe to be tested is sent into the long straight solenoid through the calibration carrier, and the position to which the standard probe is sent is the same as the position to which the probe to be tested is sent; Use a digital multimeter to connect the signal output terminal of the probe to be tested, and read the voltage value 2 generated by the probe to be tested under the alternating magnetic field; The target effective area of ​​the probe to be tested is calculated using the voltage value 1 and the voltage value 2 and based on the standard effective area of ​​the standard probe.

8. A method for calibrating a magnetic probe for magnetic confinement fusion according to claim 7, characterized in that: The standard effective area of ​​the standard probe is specifically: Wherein, (nA)0 represents the standard effective area of ​​the standard probe, n0 represents the known number of turns of the winding wire, D represents the outer diameter of the cylindrical frame, δD represents the outer diameter tolerance of the cylindrical frame, d represents the outer diameter of the winding wire, and δd represents the outer diameter tolerance of the winding wire.

9. A method for calibrating a magnetic probe for magnetic confinement fusion according to claim 7, characterized in that: The target effective area of ​​the probe to be tested is specifically: Wherein, nA represents the target effective area of ​​the probe to be tested, ξ represents the voltage value 2 generated by the probe to be tested under the alternating magnetic field, ξ0 represents the voltage value 1 generated by the standard probe under the alternating magnetic field, and (nA)0 represents the standard effective area of ​​the standard probe.

10. Use of a magnetic probe calibration device for magnetic confinement fusion according to any one of claims 1 to 6 in calibrating the effective area of ​​a magnetic probe.

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