Magnetic field analysis method and system for PCM focusing system based on equivalent model

Abstract

The present invention discloses a magnetic field analysis method and system for a PCM focusing system based on an equivalent model, and relates to the field of microwave electric vacuum technology. The key points of the technical solution are: equating a magnetic block to a corresponding rectangular current cylinder; calculating the first axial magnetic field generated by a single pair of rectangular coils at a target space point; calculating the second axial magnetic field generated by the rectangular current cylinder at the target space point in an integral manner; calculating the second axial magnetic field generated by each pair of magnetic blocks at the target space point; superimposing the second axial magnetic fields of each pair of magnetic blocks to calculate the total magnetic field; comparing the magnetic field peak value of the total magnetic field with the target magnetic field peak value and correcting the magnetization of the magnetic block, iteratively calculating until the difference between the magnetic field peak value of the total magnetic field and the target magnetic field peak value is less than a threshold value, and outputting the magnetization conditions of each magnetic block and the axial magnetic field. The present invention can calculate the target magnetic field and the specific magnetization conditions of the magnetic blocks of the PCM magnetic system in a very short time through PCM magnetic field equivalent calculation and rapid reverse design.

Description

Technical Field

[0001] The present invention relates to the field of microwave electric vacuum technology, and more specifically, to a magnetic field analysis method and system for a PCM focusing system based on an equivalent model. Background Art

[0002] Strip electron beam microwave devices use a rectangular or elliptical cross-section electron beam with a large aspect ratio, which reduces the space charge effect and expands the interaction area. They are widely used in various microwave electron tube research fields that are gradually developing towards higher radiation power and higher operating frequency.

[0003] The movement of a ribbon electron beam under uniform magnetic field focusing is unstable. As the transmission distance increases, the electron beam will be kinked and torn, which is called Diocotron instability. Fortunately, the periodic magnetic focusing structure has been proven to be able to effectively overcome this instability. In the periodic magnetic system, the biased PCM structure can provide matching focusing force for the two directions of the ribbon electron beam, so that the electron beam can have smaller fluctuations in both the wide and narrow directions. Therefore, it has significant advantages in the efficient and stable long-distance transmission of ribbon electron beams.

[0004] However, the traditional PCM magnetic system design often uses electromagnetic simulation software to perform a large number of scanning parameter calculations, and constantly tries to modify the magnetic system parameters based on experience. This process is tedious and time-consuming, and requires a lot of manual operations. It is also difficult to obtain a relatively ideal target magnetic field, which brings great trouble to the simulation design of the electron optical system. Therefore, how to study and design a PCM focusing system magnetic field analysis method and system based on an equivalent model that can overcome the above defects is a problem that we urgently need to solve. Summary of the invention

[0005] In order to address the deficiencies in the prior art, the purpose of the present invention is to provide a PCM focusing system magnetic field analysis method and system based on an equivalent model. Through PCM magnetic field equivalent calculation and rapid reverse design, the target magnetic field and the specific magnetization conditions of the magnetic blocks of the PCM magnetic system can be calculated in a very short time.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] In a first aspect, a method for analyzing a magnetic field of a PCM focusing system based on an equivalent model is provided, comprising the following steps:

[0008] According to the PCM structural parameters, the magnetic block is equivalent to the corresponding rectangular current cylinder;

[0009] Calculate the first axial magnetic field generated by a single pair of rectangular coils at a target spatial point under a target current;

[0010] The second axial magnetic field generated at the target space point under the target current after the single pair of rectangular coils is expanded into a pair of rectangular current cylinders is calculated by integral method;

[0011] The second axial magnetic field generated by each magnetic block pair at the target space point is calculated cyclically according to the magnetization and position parameters of the magnetic block pairs in the PCM structure;

[0012] The total magnetic field is calculated by superimposing the second axial magnetic fields of each magnetic block pair;

[0013] The peak value of the total magnetic field is compared with the target magnetic field peak value and the magnetization of the magnetic block is corrected. The calculation is iterated until the difference between the peak value of the total magnetic field and the target magnetic field peak value is less than the threshold value, and the magnetization status and axial magnetic field of each magnetic block are output.

[0014] Furthermore, the calculation process of the first axial magnetic field is specifically as follows:

[0015] The first magnetic field of four parallel horizontal line segments at the target space point is calculated according to the spatial distribution of a single pair of rectangular coils;

[0016] The second magnetic field of four parallel vertical line segments at the target space point is calculated according to the spatial distribution of the single pair of rectangular coils;

[0017] The first axial magnetic field is calculated according to the sum of the first magnetic field and the second magnetic field.

[0018] Furthermore, the calculation formula of the first magnetic field is specifically:

[0019]

[0020] Among them, B s1 represents the first magnetic field of four parallel horizontal line segments at the target space point; μ0 represents the vacuum magnetic permeability; π represents the pi; I represents the target current; b represents half of the width of the magnetic block; h1 represents the distance from the bottom of the magnetic block to the Z axis; h2 represents the distance from the top of the magnetic block to the Z axis; z represents the relative Z axis coordinate of the target space point and the coil, and the Z axis is the longitudinal direction of the PCM.

[0021] Furthermore, the calculation formula of the second magnetic field is specifically:

[0022]

[0023] Among them, B s2 represents the first magnetic field of four parallel vertical line segments at the target space point; μ0 represents the vacuum magnetic permeability; π represents the pi; I represents the target current; b represents half of the width of the magnetic block; h1 represents the distance from the bottom of the magnetic block to the Z axis; h2 represents the distance from the top of the magnetic block to the Z axis; z represents the relative Z axis coordinate of the target space point and the coil, and the Z axis is the longitudinal direction of the PCM.

[0024] Furthermore, the calculation formula of the second axial magnetic field is specifically:

[0025]

[0026] Among them, B M represents the second axial magnetic field; T represents the thickness of the magnetic block; z represents the relative Z-axis coordinate of the target space point and the coil, and the Z-axis is the longitudinal direction of the PCM.

[0027] Furthermore, the expression of the position parameter is specifically:

[0028] z i =z0+(i-1)L

[0029] Among them, z i represents the Z-axis coordinate of the i-th magnetic block pair relative to the target space point; z0 represents the relative Z-axis coordinate of the target space point from the starting position of the first magnetic block; L represents the PCM half cycle.

[0030] Furthermore, the magnetization correction process of the magnetic block is specifically as follows:

[0031] Calculate the difference between the peak value of the target magnetic field and the peak value of the total magnetic field;

[0032] If the absolute value of the difference is greater than the set threshold, the magnetization is corrected: when the difference is greater than 0, the magnetization increases by one magnetization step; if the difference is less than 0, the magnetization decreases by one magnetization step;

[0033] After correction, iterative calculation is performed again until the absolute values ​​of the differences are all less than the threshold.

[0034] Secondly, a PCM focusing system magnetic field analysis system based on an equivalent model is provided, including:

[0035] An equivalent model module is used to convert the magnetic block into a corresponding rectangular current cylinder according to the PCM structural parameters;

[0036] A magnetic field calculation module, used to calculate the first axial magnetic field generated by a single pair of rectangular coils at a target spatial point under a target current;

[0037] An integral processing module, used for calculating by integral method the second axial magnetic field generated at the target space point under the target current after the single pair of rectangular coils are expanded into a pair of rectangular current cylinders;

[0038] A loop processing module, used for cyclically calculating the second axial magnetic field generated by each magnetic block pair at the target space point according to the magnetization and position parameters of the magnetic block pairs in the PCM structure;

[0039] A superposition processing module, used for superimposing the second axial magnetic fields of each magnetic block pair to calculate the total magnetic field;

[0040] The correction iteration module is used to compare the magnetic field peak value of the total magnetic field with the target magnetic field peak value and correct the magnetization of the magnetic block, iteratively calculate until the difference between the magnetic field peak value of the total magnetic field and the target magnetic field peak value is less than a threshold value, and output the magnetization status and axial magnetic field of each magnetic block.

[0041] In a third aspect, a computer terminal is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the PCM focusing system magnetic field analysis method based on an equivalent model as described in any one of the first aspects is implemented.

[0042] In a fourth aspect, a computer-readable medium is provided, on which a computer program is stored, and the computer program is executed by a processor to implement the magnetic field analysis method of the PCM focusing system based on the equivalent model as described in any one of the first aspects.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The PCM focusing system magnetic field analysis method based on the equivalent model proposed in the present invention can calculate the target magnetic field and the specific magnetization conditions of the magnetic blocks of the PCM magnetic system in a very short time through PCM magnetic field equivalent calculation and rapid reverse design. Compared with the PCM simulated axial magnetic field, the maximum error is less than 3%. It can effectively solve the problem that the simulation calculation process of the PCM focusing system of the electronic optical system is too lengthy, thus wasting a lot of time and cost, and provide assistance for the rapid design of the electronic optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] 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:

[0046] Figure 1 Schematic diagram of a rectangular current cylinder equivalent to a single magnetic block in an embodiment of the present invention;

[0047] Figure 2 is a schematic diagram of the relative position relationship between a single rectangular coil and a target space point in an embodiment of the present invention;

[0048] Figure 3 is an axial view of a pair of rectangular coils in an embodiment of the present invention;

[0049] Figure 4 is a comparison diagram of the target magnetic field and the PCM simulated magnetic field in an embodiment of the present invention;

[0050] Figure 5 It is a system block diagram in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0052] Embodiment 1: A method for analyzing the magnetic field of a PCM focusing system based on an equivalent model is specifically implemented by the following steps.

[0053] (1) According to the PCM structural parameters, the magnetic block is equivalent to the corresponding rectangular current cylinder.

[0054] like Figure 1 As shown, the rectangular current tube is formed by stacking multiple rectangular coils, and the magnetic block is magnetized B r The relationship between the current density I' is B r =μ0I′, h1 and h2 are the distances from the bottom and top of the magnetic block to the Z axis respectively, 2b is the width of the magnetic block, and T is the thickness of the magnetic block.

[0055] (2) Calculate the first axial magnetic field generated by a single pair of rectangular coils at the target spatial point under the target current.

[0056] like Figure 2 and Figure 3 As shown, the first magnetic field of four parallel horizontal line segments at the target space point A is calculated according to the spatial distribution of the single pair of rectangular coils; the second magnetic field of four parallel vertical line segments at the target space point A is calculated according to the spatial distribution of the single pair of rectangular coils; finally, the first axial magnetic field is calculated according to the sum of the first magnetic field and the second magnetic field.

[0057] The calculation formula of the first magnetic field is specifically:

[0058]

[0059] Among them, B s1 represents the first magnetic field of four parallel horizontal line segments at the target space point; μ0 represents the vacuum magnetic permeability; π represents the pi; I represents the target current; b represents half of the width of the magnetic block; h1 represents the distance from the bottom of the magnetic block to the Z axis; h2 represents the distance from the top of the magnetic block to the Z axis; z represents the relative Z axis coordinate of the target space point and the coil, and the Z axis is the longitudinal direction of the PCM.

[0060] The calculation formula of the second magnetic field is as follows:

[0061]

[0062] Among them, B s2 Represents the first magnetic field of four parallel vertical line segments at the target space point.

[0063] The axial magnetic field calculation of a pair of rectangular coils at the target space point A is as follows:

[0064] B s =B s1 +B s2

[0065] Among them, B s Represents the axial magnetic field of a pair of rectangular coils at a target point in space.

[0066] (3) The second axial magnetic field generated at the target spatial point under the target current after the single pair of rectangular coils is expanded into a pair of rectangular current tubes is calculated by integral method.

[0067] The calculation formula of the second axial magnetic field is as follows:

[0068]

[0069] Among them, B M represents the second axial magnetic field;

[0070] (4) The second axial magnetic field generated by each magnetic pair at the target spatial point is calculated cyclically based on the magnetization and position parameters of the magnetic pair in the PCM structure.

[0071] Combined with the PCM magnetization of the i-th pair of magnetic blocks B ri and the position parameter z i = z0+(i-1)L, cyclically calculate the magnetic field B generated by the i-th pair of magnetic blocks at the spatial point Mi , where z0 is the relative axial coordinate of the space point from the starting position of the first magnetic block, and i and B in the expression ri , B Mi and z i The subscript i in refers to the number of the magnetic block pair, and L is the PCM half cycle.

[0072] (5) The multi-period PCM axial magnetic field is obtained by superimposing the magnetic fields of each magnetic block, and the total magnetic field is calculated by superimposing the second axial magnetic fields of each magnetic block pair:

[0073]

[0074] B Mi is calculated by taking the position parameter z i =z0+(i-1)L instead of B M The parameter z in the calculation process is the magnetic field parameter B ri Replace B M Parameter B in the calculation process r Through the above analysis, the distribution of the axial magnetic field with z can be obtained by substituting the structural parameters of PCM. The total magnetic field B is a function of the axial coordinate z.

[0075] (6) Compare the peak value of the total magnetic field with the target magnetic field peak value and correct the magnetization of the magnetic block. Iterate the calculation until the difference between the peak value of the total magnetic field and the target magnetic field peak value is less than the threshold value, and output the magnetization status and axial magnetic field of each magnetic block.

[0076] The magnetization correction process of the magnetic block is as follows: Calculate the target magnetic field peak value D i The peak value of the magnetic field P i The difference ΔP i , that is, ΔP i =D i -P i ; If the difference ΔP i If the absolute value of is greater than the set threshold, magnetization B is performed. ri Correction: When the difference is greater than 0, magnetize B ri Add a magnetizing step length ΔBr; if the difference is less than 0, the magnetizing is reduced by a magnetizing step length ΔBr; after correction, enter the iterative calculation again until the absolute value of the difference is less than the threshold ΔP, then it can be considered that the axial magnetic field distribution can achieve the target magnetic field requirements.

[0077] (7) Simulation Verification

[0078] The selected PCM structural parameters are as follows: period L = 8 mm; number of periods 5, i.e. 10 pairs of magnetic blocks; target magnetic field peak D i The initial setting of magnetization B is -0.2T, 0.2T, -0.2T, 0.2T, -0.2T, 0.2T, -0.2T, 0.2T. ri They are -1T, 1T, -1T, 1T, -1T, 1T, -1T, 1T, -1T, 1T; h1 and h2 are 2.18mm and 12.7mm respectively; the magnet width 2b = 18mm, the magnet thickness T = 2.72mm, the step size ΔBr = 0.005T, and the threshold ΔP = 0.001T. The magnetization of the magnet blocks obtained by this design method are: -0.875T, 0.093T, -1.025T, 0.98T, -1T, 1.005T, -0.97T, 1.03T, -0.925T, 0.88T. The comparison between the calculated target magnetic field and the PCM simulated axial magnetic field designed according to the present invention is as follows. Figure 4 As shown, the degree of conformity is high and the maximum error is less than 3%. This result can prove the feasibility of this method.

[0079] Embodiment 2: A PCM focusing system magnetic field analysis system based on an equivalent model, the system is used to implement the analysis method described in Embodiment 1, such as Figure 5 As shown, it includes an equivalent model module, a magnetic field calculation module, an integral processing module, a loop processing module, a superposition processing module and a correction iteration module.

[0080] Among them, the equivalent model module is used to equate the magnetic block to the corresponding rectangular current cylinder according to the PCM structure parameters; the magnetic field calculation module is used to calculate the first axial magnetic field generated by a single pair of rectangular coils at the target space point under the target current; the integral processing module is used to calculate the second axial magnetic field generated by the single pair of rectangular coils at the target space point under the target current after being expanded to a pair of rectangular current cylinders in an integral manner; the loop processing module is used to loop calculate the second axial magnetic field generated by each magnetic block pair at the target space point according to the magnetization and position parameters of the magnetic block pairs in the PCM structure; the superposition processing module is used to superimpose the second axial magnetic fields of each magnetic block pair to calculate the total magnetic field; the correction iteration module is used to compare the magnetic field peak value of the total magnetic field with the target magnetic field peak value and correct the magnetization of the magnetic block, iteratively calculate until the difference between the magnetic field peak value of the total magnetic field and the target magnetic field peak value is less than the threshold value, and output the magnetization status and axial magnetic field of each magnetic block.

[0081] Working principle: The present invention can calculate the target magnetic field and the specific magnetization conditions of the magnetic blocks of the PCM magnetic system in a very short time through PCM magnetic field equivalent calculation and rapid reverse design. Compared with the PCM simulated axial magnetic field, the maximum error is less than 3%. It can effectively solve the problem that the simulation calculation process of the PCM focusing system of the electronic optical system is too lengthy, thus wasting a lot of time and cost, and provide assistance for the rapid design of the electronic optical system.

[0082] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0083] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0084] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0085] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0086] 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 field analysis method for a PCM focusing system based on an equivalent model, characterized in that: The following steps are involved: According to the PCM structural parameters, the magnetic block is equivalent to the corresponding rectangular current cylinder; Calculate the first axial magnetic field generated by a single pair of rectangular coils at a target spatial point under a target current; The second axial magnetic field generated at the target space point under the target current after the single pair of rectangular coils is expanded into a pair of rectangular current cylinders is calculated by integral method; The second axial magnetic field generated by each magnetic block pair at the target space point is calculated cyclically according to the magnetization and position parameters of the magnetic block pairs in the PCM structure; The total magnetic field is calculated by superimposing the second axial magnetic fields of each magnetic block pair; Compare the peak value of the total magnetic field with the target magnetic field peak value and correct the magnetization of the magnetic block, iterate the calculation until the difference between the peak value of the total magnetic field and the target magnetic field peak value is less than the threshold value, and output the magnetization status and axial magnetic field of each magnetic block; The calculation process of the first axial magnetic field is specifically as follows: The first magnetic field of four parallel horizontal line segments at the target space point is calculated according to the spatial distribution of a single pair of rectangular coils; The second magnetic field of four parallel vertical line segments at the target space point is calculated according to the spatial distribution of the single pair of rectangular coils; The first axial magnetic field is calculated according to the sum of the first magnetic field and the second magnetic field; The expression of the position parameter is specifically: z i =z0+(i-1)L Among them, z i represents the Z-axis coordinate of the i-th magnetic block pair relative to the target space point; z0 represents the relative Z-axis coordinate of the target space point from the starting position of the first magnetic block; L represents the PCM half cycle.

2. The method for analyzing the magnetic field of a PCM focusing system based on an equivalent model according to claim 1 is characterized in that: The calculation formula of the first magnetic field is specifically: Among them, B s1 represents the first magnetic field of four parallel horizontal line segments at the target space point; μ0 represents the vacuum magnetic permeability; π represents the pi; I represents the target current; b represents half of the width of the magnetic block; h1 represents the distance from the bottom of the magnetic block to the Z axis; h2 represents the distance from the top of the magnetic block to the Z axis; z represents the relative Z axis coordinate of the target space point and the coil, and the Z axis is the longitudinal direction of the PCM.

3. The method for analyzing the magnetic field of a PCM focusing system based on an equivalent model according to claim 1 is characterized in that: The calculation formula of the second magnetic field is specifically: Among them, B s2 represents the first magnetic field of four parallel vertical line segments at the target space point; μ0 represents the vacuum magnetic permeability; π represents the pi; I represents the target current; b represents half of the width of the magnetic block; h1 represents the distance from the bottom of the magnetic block to the Z axis; h2 represents the distance from the top of the magnetic block to the Z axis; z represents the relative Z axis coordinate of the target space point and the coil, and the Z axis is the longitudinal direction of the PCM.

4. The method for analyzing the magnetic field of a PCM focusing system based on an equivalent model according to claim 1 is characterized in that: The calculation formula of the second axial magnetic field is specifically: Among them, B M represents the second axial magnetic field; T represents the thickness of the magnetic block; z represents the relative Z-axis coordinate of the target space point and the coil, and the Z axis is the longitudinal direction of the PCM; B s Represents the axial magnetic field of a pair of rectangular coils at a target point in space.

5. The PCM focusing system magnetic field analysis method based on an equivalent model according to any one of claims 1 to 4, characterized in that: The magnetization correction process of the magnetic block is specifically as follows: Calculate the difference between the peak value of the target magnetic field and the peak value of the total magnetic field; If the absolute value of the difference is greater than the set threshold, the magnetization is corrected: when the difference is greater than 0, the magnetization is increased by one magnetization step; If the difference is less than 0, the magnetization is reduced by one magnetization step; After correction, iterative calculation is performed again until the absolute values ​​of the differences are all less than the threshold.

6. A PCM focusing system magnetic field analysis system based on an equivalent model, characterized in that: The system is used to implement the PCM focusing system magnetic field analysis method based on an equivalent model as described in any one of claims 1 to 5, comprising: An equivalent model module is used to convert the magnetic block into a corresponding rectangular current cylinder according to the PCM structural parameters; A magnetic field calculation module, used to calculate the first axial magnetic field generated by a single pair of rectangular coils at a target spatial point under a target current; An integral processing module, used for calculating by integral method the second axial magnetic field generated at the target space point under the target current after the single pair of rectangular coils are expanded into a pair of rectangular current cylinders; A loop processing module, used for cyclically calculating the second axial magnetic field generated by each magnetic block pair at the target space point according to the magnetization and position parameters of the magnetic block pairs in the PCM structure; A superposition processing module, used for superimposing the second axial magnetic fields of each magnetic block pair to calculate the total magnetic field; The correction iteration module is used to compare the magnetic field peak value of the total magnetic field with the target magnetic field peak value and correct the magnetization of the magnetic block, iteratively calculate until the difference between the magnetic field peak value of the total magnetic field and the target magnetic field peak value is less than a threshold value, and output the magnetization status and axial magnetic field of each magnetic block.

7. A computer terminal comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the PCM focusing system magnetic field analysis method based on the equivalent model as described in any one of claims 1 to 5 is implemented.

8. A computer readable medium having a computer program stored thereon, characterized in that: The computer program is executed by a processor to implement the PCM focusing system magnetic field analysis method based on an equivalent model as described in any one of claims 1 to 5.

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