Parameter determination method of multi-stage buck collector and multi-stage buck collector

Abstract

The present disclosure provides a method for determining parameters of a multi-stage buck collector, the method comprising: determining an initial electrode size of each of a plurality of electrodes of the multi-stage buck collector according to a performance evaluation index of a gyrotron and a process evaluation index of the multi-stage buck collector, the performance evaluation index including the power generated by the gyrotron, and the multi-stage buck collector being used to dissipate the power generated by the gyrotron; determining an initial voltage drop of each electrode according to the energy distribution of waste electron injection generated in the gyrotron; determining an initial tilt parameter of at least one of the plurality of electrodes according to the arrangement of the plurality of electrodes; adjusting the initial electrode size, initial voltage drop and initial tilt parameter until the collection efficiency and reflux rate of the multi-stage buck collector meet a first preset condition; determining the electrode size, voltage drop and tilt parameter obtained when the first preset condition is met as a target electrode size, target voltage drop and target tilt parameter of the multi-stage buck collector.

Description

Technical Field

[0001] The present disclosure relates to the field of a gyrotron multi-stage step-down collector, and more specifically to a method for determining parameters of a multi-stage step-down collector and a multi-stage step-down collector. Background Art

[0002] Controlled nuclear fusion is a clean energy that can replace fossil fuels in the future. Controlled nuclear fusion has the advantages of high energy release, abundant reserves, no pollution and safety. The 170GHz megawatt-class gyrotron is an ideal power source for plasma-assisted heating and current drive in controlled nuclear fusion. The collector, as the end component of the gyrotron, plays the role of recovering and dissipating the waste electron beam energy generated by the electromagnetic wave energy exchange between the electron beam and the high-frequency field in the gyrotron interaction cavity.

[0003] In the process of realizing the inventive concept of the present disclosure, the inventors found that the following problems generally exist in the related technology: in the process of recycling the waste electron injection energy and dissipating the power of the collector, there will be secondary electron emission, and the existence of secondary electron emission will reduce the collection efficiency of the collector and increase the reflux rate of the collector. Summary of the invention

[0004] In view of the above problems, the present disclosure provides a method for determining parameters of a multi-stage step-down collector and a multi-stage step-down collector for improving the collection efficiency of the collector.

[0005] The first aspect of the present disclosure provides a method for determining parameters of a multi-stage buck collector, comprising: determining an initial electrode size of each of a plurality of electrodes of the multi-stage buck collector according to a performance evaluation index of a gyrotron and a process evaluation index of the multi-stage buck collector, wherein the performance evaluation index includes the power generated by the gyrotron, and the multi-stage buck collector is used to dissipate the power generated by the gyrotron; determining an initial voltage drop of each of the plurality of electrodes according to the energy distribution of waste electron injection generated in the gyrotron; determining an initial tilt parameter of at least one of the plurality of electrodes according to the arrangement of the plurality of electrodes; adjusting the initial electrode size, the initial voltage drop and the initial tilt parameter until the collection efficiency and the reflux rate of the multi-stage buck collector meet a first preset condition; determining the electrode size, the voltage drop and the tilt parameter obtained when the first preset condition is met as the target electrode size, the target voltage drop and the target tilt parameter of the multi-stage buck collector.

[0006] According to an embodiment of the present disclosure, the above method also includes: adding a magnetic field around the above multi-stage buck collector and determining the initial magnetic field parameters; adjusting the above initial magnetic field parameters until the maximum power density of the above multi-stage buck collector meets the second preset condition; and determining the magnetic field parameters obtained when the above second preset condition is met as the target magnetic field parameters of the above multi-stage buck collector.

[0007] According to an embodiment of the present disclosure, the above-mentioned initial tilt parameters include an initial tilt angle and an initial axial length; the above-mentioned adjustment of the above-mentioned initial electrode size, the above-mentioned initial voltage drop and the above-mentioned initial tilt parameters until the collection efficiency and the reflux rate of the above-mentioned multi-stage step-down collector meet the first preset condition includes: setting the above-mentioned initial tilt angle to a constant value, adjusting the above-mentioned initial axial length according to a first preset ratio to obtain a target axial length; adjusting the above-mentioned initial tilt angle according to a second preset ratio according to the target axial length until the collection efficiency and the reflux rate of the above-mentioned multi-stage step-down collector meet the first preset condition; and determining the tilt angle obtained under the condition of satisfying the above-mentioned first preset condition as the target tilt angle of the above-mentioned multi-stage step-down collector.

[0008] According to an embodiment of the present disclosure, determining the initial voltage drop of each of the multiple electrodes according to the waste electron injection energy distribution generated in the gyrotron includes: determining the voltage drop difference between every two adjacent electrodes of the multiple electrodes according to the range of the waste electron injection energy distribution; and determining the initial voltage drop of each of the multiple electrodes according to the voltage drop difference.

[0009] According to an embodiment of the present disclosure, the above-mentioned magnetic field includes a first magnetic field generated by a first direction spiral coil and a second magnetic field generated by a second direction spiral coil; a magnetic field is added around the above-mentioned multi-stage step-down collector, including: passing cosine alternating current through the above-mentioned first direction spiral coil to obtain the above-mentioned first magnetic field that rotates dynamically; passing direct current through the above-mentioned second direction spiral coil to obtain the above-mentioned second magnetic field that rotates dynamically.

[0010] According to an embodiment of the present disclosure, the magnetic field parameters include: a first initial axial position of the first direction spiral coil, a second initial axial position of the second direction spiral coil, a first initial current amplitude of the cosine alternating current, and a second initial current amplitude of the direct current.

[0011] According to an embodiment of the present disclosure, the above-mentioned adjustment of the initial magnetic field parameters until the maximum power density of the above-mentioned multi-stage buck collector meets the second preset condition includes: adjusting the above-mentioned first initial axial position according to a third preset ratio, and adjusting the above-mentioned first initial current amplitude according to a fourth preset ratio, until the maximum power density of the above-mentioned multi-stage buck collector meets the second preset condition; the first axial position and the first current amplitude obtained when the above-mentioned second preset condition is met are determined as the first target axial position and the first target current amplitude of the above-mentioned multi-stage buck collector.

[0012] According to an embodiment of the present disclosure, the above-mentioned adjustment of the initial magnetic field parameters until the maximum power density of the above-mentioned multi-stage buck collector meets the second preset condition also includes: adjusting the above-mentioned second initial axial position according to a third preset ratio, and adjusting the above-mentioned second initial current amplitude according to a fourth preset ratio until the maximum power density of the above-mentioned multi-stage buck collector meets the second preset condition; the second axial position and the second current amplitude obtained when the above-mentioned second preset condition is met are determined as the second target axial position and the second target current amplitude of the above-mentioned multi-stage buck collector.

[0013] Another aspect of the present disclosure also provides a multi-stage buck collector, comprising: a plurality of electrodes arranged inside the multi-stage buck collector, at least one of the plurality of electrodes being arranged at an angle, wherein the parameters of each of the plurality of electrodes include a target electrode size, a target tilt parameter, and a target voltage drop; a spiral coil arranged around the multi-stage buck collector for generating a magnetic field; wherein the target electrode size, the target tilt parameter, the target voltage drop, and the magnetic field parameters of the magnetic field are determined by the parameter determination method of the multi-stage buck collector.

[0014] According to an embodiment of the present disclosure, the above-mentioned multiple electrodes include a first electrode, a second electrode, a third electrode and a fourth electrode; the above-mentioned first electrode, the above-mentioned second electrode, the above-mentioned third electrode and the above-mentioned fourth electrode are arranged in sequence, and the above-mentioned fourth electrode is used as the end electrode of the multi-stage step-down collector and is arranged obliquely.

[0015] According to the parameter determination method of the multi-stage step-down collector provided by the embodiment of the present disclosure, by tilting at least one electrode among the multiple electrodes, determining the tilt parameter, and continuously adjusting the electrode size, voltage drop and tilt parameter, until the collection efficiency and reflux rate of the multi-stage step-down collector meet the first preset condition, because the electrode is tilted, the secondary electrons can be forced to collide with the electrode, so that the secondary electrons are recovered by the electrode again, thereby reducing the number of secondary electrons flowing back to the interaction cavity, and reducing the adverse effects of secondary electron emission. At least partially overcome the problems of low collection efficiency and high reflux rate caused by secondary electrons in the related art, and achieve the technical effect of improving the collection efficiency of the collector and reducing the recovery rate of the collector. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0017] Figure 1 A flow chart schematically shows a method for determining parameters of a multi-stage buck collector according to an embodiment of the present disclosure;

[0018] Figure 2 Schematically shows a structural diagram of a multi-stage buck collector according to an embodiment of the present disclosure;

[0019] Figure 3 A diagram schematically shows the energy distribution of a waste electron beam after the electron beam interacts with an electromagnetic wave in a gyrotron interaction cavity according to an embodiment of the present disclosure;

[0020] Figure 4 The electron emission trajectory diagram of the multi-stage buck collector according to the embodiment of the present disclosure is schematically shown;

[0021] Figure 5 A schematic diagram of a magnetic field scanning structure according to an embodiment of the present disclosure is shown;

[0022] Figure 6 The wall power density distribution diagram of the multi-stage buck collector according to the embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0024] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0025] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0026] In the case of using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, or C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0027] Since the energy exchange efficiency between the electron beam and the high-frequency field in the gyrotron interaction cavity is low, generally 30-35%, when the output power of the gyrotron reaches the megawatt level, the residual energy carried by the waste electron beam remains at a very high level, and the residual energy often reaches the megawatt level. However, the collector has a certain limit to its ability to recover and dissipate energy. For the collector, oxygen-free copper is generally used. The upper limit of the power density that oxygen-free copper can withstand is 500W / cm 2 The megawatt-level dissipation power can easily exceed this upper limit, which will cause the collector to melt or evaporate to form copper evaporation, which will reduce the vacuum degree in the gyrotron body and even damage the gyrotron. In addition, the low interaction efficiency between the electron beam and the high-frequency field in the gyrotron interaction cavity also limits the improvement of the total output efficiency of the gyrotron.

[0028] In order to improve the performance of megawatt-level gyrotron collectors, many researchers have conducted research on step-down collectors. In a 2013 paper published by A. Kumar et al. of the Indian CEERI Institute (A. Kumar, N. Kumar, U. Singh, et al., “Towards a 1MW, 170GHz gyrotron design for fusion application,” in Infrared Physics and Technology, vol. 57, no. 1, pp. 1-7, 2013), a single-stage step-down collector structure was described. Without considering secondary electron emission, the collector efficiency can reach 64%, and the maximum power density of the collector wall is 430W / cm 2 A. Singh et al. from the University of Maryland, USA, published a paper in 1999 (A. Singh, S. Rajapatirana, Y. Men, et al., “Design of a multistage depressed collector system of 1-MW CW gyrotrons. I. Trajectory control of primary and secondary electrons in a two-stage depressed collector,” in IEEE Transactions on Plasma Science, vol. 27, no. 2, pp. 490-502, 1999.) describing a two-stage depressed collector structure with a collection efficiency of 68%. After considering the secondary electron emission, the collection efficiency drops to 60%.

[0029] In the above method, it is not only confirmed that the presence of secondary electrons will reduce the collection efficiency of the collector, but also that the maximum power density of the wall of the step-down collector is at a higher level. In general, the diffusion capacity of the collector to the waste electron injection settling area is limited, so it is easy to generate local high temperature. In particular, when the output power of the device continues to increase (for example, from 1 MW to 2 MW), the maximum power density of the collector wall is more likely to exceed the tolerance value of the material used in the device, which is 500W / cm 2 In addition, secondary electron emission is an important factor affecting the performance of the collector, which can easily reduce the collection efficiency of the collector, increase the reflux rate and increase the wall dissipation. Therefore, further research on the collector is needed to improve the collection efficiency of the collector, reduce the reflux rate and reduce the maximum power density.

[0030] In view of this, the embodiment of the present disclosure provides a method for determining parameters of a multi-stage buck collector and a multi-stage buck collector to improve the collection efficiency, reduce the reflux rate and reduce the maximum power density. Specifically, the method includes determining the initial electrode size of each of the multiple electrodes of the multi-stage buck collector according to the performance evaluation index of the gyrotron and the process evaluation index of the multi-stage buck collector, wherein the performance evaluation index includes the power generated by the gyrotron, and the multi-stage buck collector is used to dissipate the power generated by the gyrotron; determining the initial voltage drop of each of the multiple electrodes according to the energy distribution of the waste electron injection generated in the gyrotron; determining the initial tilt parameter of at least one of the multiple electrodes according to the arrangement of the multiple electrodes; adjusting the initial electrode size, initial voltage drop and initial tilt parameter until the collection efficiency and reflux rate of the multi-stage buck collector meet the first preset condition; determining the electrode size, voltage drop and tilt parameter obtained when the first preset condition is met as the target electrode size, target voltage drop and target tilt parameter of the multi-stage buck collector.

[0031] Figure 1 The flowchart of the method for determining parameters of a multi-stage buck collector according to an embodiment of the present disclosure is schematically shown.

[0032] like Figure 1 As shown, the parameter determination method of the multi-stage buck collector of this embodiment includes operations S101 to S105.

[0033] In operation S101, the initial electrode size of each of the multiple electrodes of the multi-stage buck collector is determined according to the performance evaluation index of the gyrotron and the process evaluation index of the multi-stage buck collector, wherein the performance evaluation index includes the power generated by the gyrotron, and the multi-stage buck collector is used to dissipate the power generated by the gyrotron.

[0034] In operation S102 , an initial voltage drop of each of a plurality of electrodes is determined according to energy distribution of waste electron beams generated in the gyrotron.

[0035] In operation S103, an initial tilt parameter of at least one electrode among the plurality of electrodes is determined according to the arrangement of the plurality of electrodes.

[0036] In operation S104, the initial electrode size, the initial voltage drop, and the initial tilt parameters are adjusted until the collection efficiency and the reflux rate of the multi-stage step-down collector meet a first preset condition.

[0037] In operation S105, the electrode size, voltage drop and tilt parameters obtained when the first preset condition is met are determined as the target electrode size, target voltage drop and target tilt parameters of the multi-stage buck collector.

[0038] According to an embodiment of the present disclosure, the performance evaluation index may be the power to be dissipated generated by the gyrotron, which is dissipated by the collector. The process evaluation index may be the process level that is currently capable of processing the collector, and the initial electrode size may be the lateral structural size of the electrode, which may be understood as the radius of the electrode. Operation S110 may also be understood as determining the lateral structural size of the electrode by the power level that the gyrotron collector needs to dissipate and the processing technology level of the collector. The greater the power that the gyrotron collector needs to dissipate and the higher the processing technology level of the collector, the larger the lateral structural size of the electrode may be.

[0039] Figure 2 The structure diagram of a multi-stage buck collector according to an embodiment of the present disclosure is schematically shown.

[0040] like Figure 2 As shown, the multi-stage step-down collector provided in the embodiment of the present disclosure can be set at the end of a 170GHz megawatt-class gyrotron, so the power level that the collector needs to dissipate needs to reach the megawatt level. Therefore, within the range allowed by the current collector processing technology, the electrode size A can not exceed 300mm, and this size can also be adaptively adjusted according to actual needs.

[0041] The arrangement of each step-down electrode can refer to Figure 2 , the multi-stage buck collector may include 4 electrodes, specifically, 4 buck electrodes, which are arranged inside the multi-stage buck collector. For example, the first buck electrode 1, the second buck electrode 2, the third buck electrode 3, and the fourth buck electrode 4. The first buck electrode 1, the second buck electrode 2, the third buck electrode 3, and the fourth buck electrode 4 can be arranged in sequence. For example, the first buck electrode 1, the second buck electrode 2, and the third buck electrode 3 can be arranged on one side; the fourth buck electrode 4 can be arranged on the other side. Among them, the first buck electrode 1, the second buck electrode 2, and the fourth buck electrode 4 can be arranged obliquely, and the third buck electrode 3 can be arranged horizontally in the X direction. The fourth buck electrode 4 can be used as the end electrode of the multi-stage buck collector, and is inclined to be sloped.

[0042] According to the embodiments of the present disclosure, since the efficiency of the energy exchange between the electron beam and the electromagnetic wave of the high-frequency field in the gyrotron is low, the total output efficiency of the entire tube is greatly limited. The collector composed of multiple step-down electrodes can use multiple separated step-down electrodes to gradually slow down the waste electron beam and recover it in stages. Thereby, the energy of the waste electron beam can be recovered to the maximum extent, and the kinetic energy of the waste electron beam can be converted into electric potential energy and returned to the power supply, which will greatly improve the collection efficiency and effectively improve the total output efficiency of the entire tube. In addition, the use of multiple step-down electrodes can also reduce the total dissipated power settled on the wall of the collector.

[0043] According to an embodiment of the present disclosure, operation S102 may further include the following operations: determining a voltage drop difference between every two adjacent electrodes among the plurality of electrodes according to a range of waste electron beam energy distribution; and determining an initial voltage drop of each electrode among the plurality of electrodes according to the voltage drop difference.

[0044] Figure 3 The energy distribution diagram of the waste electron beam after the interaction between the electron beam and the electromagnetic wave in the gyrotron interaction cavity according to the embodiment of the present disclosure is schematically shown.

[0045] like Figure 3 As shown, the horizontal axis is the waste electron energy and the vertical axis is the current. The waste electron energy distribution range after the electron beam in the gyrotron interaction cavity interacts with the electromagnetic wave can be 35keV to 95keV. In this case, it can be preliminarily determined that the voltage drop difference between every two adjacent electrodes in the four electrodes can be 15eV. Combined with the minimum waste electron energy of 35keV, and the need to leave a certain margin in the voltage drop to avoid the waste electron beam from flowing back to the interaction cavity, the voltage drop difference of the first step-down electrode 1 can be set to -20kV. If determined based on the interaction cavity voltage of 80kV, it can be preliminarily determined that the initial voltage drop of the first step-down electrode 1 is 60kV, the initial voltage drop of the second step-down electrode 2 is 45kV, the initial voltage drop of the third step-down electrode 3 is 30kV, and the initial voltage drop of the fourth step-down electrode 4 is 15kV.

[0046] According to an embodiment of the present disclosure, operation S103 may also include the following operations: improving the collection efficiency of the collector and reducing the reflux rate of the collector by optimizing and adjusting the initial voltage drop. Specifically, the voltage drop difference can be adjusted on the basis of the initial voltage drop to improve the collection rate and reduce the recovery rate. Optionally, the initial voltage drop of each step-down electrode is adjusted separately. For example, when the initial voltage drop of the first step-down electrode 1 is 58 kV, the initial voltage drop of the second step-down electrode 2 is 52 kV, the initial voltage drop of the third step-down electrode 3 is 38 kV, and the initial voltage drop of the fourth step-down electrode 4 is 18 kV, the collection efficiency can reach 71.3%, the reflux rate can be reduced to 0.71%, and the total output efficiency of the gyrotron can be increased to 65.2%.

[0047] According to an embodiment of the present disclosure, the initial tilt parameter may be set with the tilt of the fourth buck electrode as a reference, and specifically, the initial tilt parameter may include an initial tilt angle θ and an initial axial length L. Operation S103 may also include the following operations: setting the initial tilt angle to a fixed value, adjusting the initial axial length according to a first preset ratio to obtain a target axial length; adjusting the initial tilt angle according to a second preset ratio according to the target axial length until the collection efficiency and the reflux rate of the multi-stage buck collector meet a first preset condition; and determining the tilt angle obtained when the first preset condition is met as the target tilt angle of the multi-stage buck collector.

[0048] According to the embodiments of the present disclosure, the inclination angle θ and the axial length L of the fourth step-down electrode can be optimized. For example, a small inclination angle θ (e.g., 1°) can be selected first, and then the axial length L value is adjusted according to a first preset ratio, for example, according to a step value of 10 mm. After obtaining the target axial length L value, the inclination angle θ is adjusted according to a second preset ratio, for example, according to a step value of 0.2°, so that the magnitude of the decrease in collection efficiency and the magnitude of the increase in reflux rate caused by secondary electrons are reduced as much as possible. Optionally, in the embodiments of the present disclosure, when the axial length L of the fourth step-down electrode 4 is L=870 mm and the inclination angle θ=9.8°, the collection efficiency can reach 71.3%, the reflux rate can be reduced to 0.71%, and the total output efficiency of the gyrotron can be increased to 65.2%.

[0049] Figure 4 The electron emission trajectory diagram of the multi-stage buck collector according to an embodiment of the present disclosure is schematically shown.

[0050] According to the embodiment of the present disclosure, when the electrode structure size is 300 mm; the initial voltage drop of the first step-down electrode 1 is 58 kV, the initial voltage drop of the second step-down electrode 2 is 52 kV, the initial voltage drop of the third step-down electrode 3 is 38 kV, and the initial voltage drop of the fourth step-down electrode 4 is 18 kV; and when the axial length L of the fourth step-down electrode 4 is 870 mm and the inclination angle θ is 9.8°, the electron emission trajectory diagram obtained can be as follows: Figure 4 As shown. Figure 4 It can be seen that by setting the above parameters, the adverse effects of secondary electron emission are effectively weakened, and most of the electrons are recovered by the step-down electrode of the collector. At this time, the reflux rate can be reduced to 0.71%, and the collection efficiency can reach 71.3%, thereby increasing the total output efficiency of the gyrotron to 65.2%.

[0051] According to an embodiment of the present disclosure, the fourth step-down electrode at the end of the collector is tilted into a slope shape, so that the lateral (along the X direction) electric field component is increased, forcing the secondary electrons to collide with the step-down electrode under the action of the lateral electric field force and be recovered by the step-down electrode, thereby reducing the number of secondary electrons flowing back to the interaction cavity, thereby reducing the adverse effects of secondary electron emission.

[0052] According to an embodiment of the present disclosure, the collection efficiency of the collector can represent all the power collected, including waste electron injection power and non-waste electron injection power. The reflux rate of the collector can represent the current flowing back into the gyrotron interaction cavity. Specifically, the collection efficiency of the collector can be shown as formula (1), and the reflux rate of the collector can be shown as formula (2).

[0053]

[0054] Among them, η c represents the collection efficiency, P c Indicates the power collected by the collector, P sb represents the waste electron injection power collected by the collector, and P sb The beam-wave interaction efficiency η can also be expressed as e and electron injection power P beam Adjusting the electrode size, voltage drop, tilt parameters, and magnetic field parameters will change the power dissipated by the collector, thereby affecting the collection efficiency of the collector.

[0055]

[0056] Among them, I b represents the current flowing back to the interaction cavity, and I0 represents the current entering the collector. Adjusting the electrode size, voltage drop, tilt parameter, and magnetic field parameter will change the current flowing back to the gyrotron interaction cavity, thereby affecting the return efficiency of the collector.

[0057] According to an embodiment of the present disclosure, the first preset condition may be a condition when the collection efficiency and the reflux rate of the collector have reached an optimal state. The optimal state may be the highest collection efficiency, the lowest reflux rate, and the highest total output efficiency. If at this time, at least one of the electrode size, voltage drop, and tilt parameter is adjusted, at least one of the collection efficiency, reflux rate, and total output efficiency will deteriorate. At this time, there is no need to adjust the electrode size, voltage drop, and tilt parameter. When there is no need to adjust the electrode size, voltage drop, and tilt parameter, it can be confirmed that the first preset condition is met. In an embodiment of the present disclosure, the optimal state may be that the collection efficiency reaches 71.3%, the reflux rate is reduced to 0.71%, and the total output efficiency of the gyrotron is increased to 65.2%. The first preset condition can also be adaptively adjusted according to actual conditions.

[0058] According to the parameter determination method of the multi-stage step-down collector provided by the embodiment of the present disclosure, by tilting at least one electrode among the multiple electrodes, determining the tilt parameter, and continuously adjusting the electrode size, voltage drop and tilt parameter, until the collection efficiency and reflux rate of the multi-stage step-down collector meet the first preset condition, because the electrode is tilted, the secondary electrons can be forced to collide with the electrode, so that the secondary electrons are recovered by the electrode again, thereby reducing the number of secondary electrons flowing back to the interaction cavity, and reducing the adverse effects of secondary electron emission. At least partially overcome the problems of low collection efficiency and high reflux rate caused by secondary electrons in the related art, and achieve the technical effect of improving the collection efficiency of the collector and reducing the recovery rate of the collector.

[0059] According to the embodiments of the present disclosure, the maximum power density of the wall of the step-down collector in the related art is at a relatively high level. In general, the diffusion capacity of the collector to the waste electron beam settling area is limited, so it is easy to generate local high temperature. In particular, when the output power of the device continues to increase, the maximum power density of the collector wall is often easy to exceed the tolerance value of the material. Therefore, in order to ensure that the maximum power density of the collector wall is still within a safe range under the high output power of the gyrotron, it is necessary to increase the diffusion length of the waste electron beam settling area and reduce the maximum power density value, thereby effectively improving the power capacity of the collector.

[0060] In view of this, the embodiments of the present disclosure add a magnetic field around the multi-stage buck collector and determine the initial magnetic field parameters; adjust the initial magnetic field parameters until the maximum power density of the multi-stage buck collector meets the second preset condition; and determine the magnetic field parameters obtained when the second preset condition is met as the target magnetic field parameters of the multi-stage buck collector.

[0061] According to an embodiment of the present disclosure, the magnetic field may include a first magnetic field generated by a first direction spiral coil and a second magnetic field generated by a second direction spiral coil; adding a magnetic field around a multi-stage step-down collector may include: passing cosine alternating current through the first direction spiral coil to obtain a dynamically rotating first magnetic field; passing direct current through the second direction spiral coil to obtain a dynamically rotating second magnetic field.

[0062] According to an embodiment of the present disclosure, the magnetic field parameters may include: a first initial axial position of the first direction spiral coil, a second initial axial position of the second direction spiral coil, a first initial current amplitude of the cosine alternating current, and a second initial current amplitude of the direct current.

[0063] According to an embodiment of the present disclosure, adjusting the initial magnetic field parameters until the maximum power density of the multi-stage buck collector meets the second preset condition may include: adjusting the first initial axial position according to a third preset ratio, and adjusting the first initial current amplitude according to a fourth preset ratio, until the maximum power density of the multi-stage buck collector meets the second preset condition; and determining the first axial position and the first current amplitude obtained when the second preset condition is met as the first target axial position and the first target current amplitude of the multi-stage buck collector.

[0064] According to an embodiment of the present disclosure, adjusting the initial magnetic field parameters until the maximum power density of the multi-stage buck collector meets the second preset condition may also include: adjusting the second initial axial position according to a third preset ratio, and adjusting the second initial current amplitude according to a fourth preset ratio, until the maximum power density of the multi-stage buck collector meets the second preset condition; and determining the second axial position and the second current amplitude obtained when the second preset condition is met as the second target axial position and the second target current amplitude of the multi-stage buck collector.

[0065] Figure 5 The figure schematically shows a magnetic field scanning structure diagram according to an embodiment of the present disclosure.

[0066] like Figure 5 As shown, the first direction spiral coil 5 may be a transverse magnetic field scanning coil, and the second direction spiral coil 6 may be a longitudinal magnetic field scanning coil. The first magnetic field may be a transverse magnetic field generated by the transverse magnetic field scanning coil; the second magnetic field may be a longitudinal magnetic field generated by the longitudinal magnetic field scanning coil. The first initial axial position of the first direction spiral coil may be the initial axial position of the transverse magnetic field scanning coil; the second initial axial position of the second direction spiral coil may be the initial axial position of the longitudinal magnetic field scanning coil.

[0067] According to the embodiments of the present disclosure, six (three pairs) uniformly distributed transverse magnetic field spiral coils may be provided to generate a transverse magnetic field, and one longitudinal magnetic field spiral coil may be provided to generate a longitudinal magnetic field. The transverse magnetic field scanning coil may be excited by cosine alternating current to generate a dynamically rotating transverse scanning magnetic field, and the transverse magnetic field scanning coil may be powered by a 50 Hz three-phase alternating current power supply. The longitudinal field coil may be excited by direct current to generate a static longitudinal magnetic field.

[0068] According to an embodiment of the present disclosure, the initial axial position of the transverse magnetic field scanning coil and the first initial current amplitude of the cosine alternating current can be adjusted to increase the diffusion area of ​​the waste electron beam, so that the maximum power density of the collector is reduced. Specifically, the initial axial position of the transverse magnetic field scanning coil can be initially at 1000 mm, and gradually increase at a third preset ratio, such as a step value of 10 mm, and the first initial current amplitude can be initially at 100 A, and gradually increase at a fourth preset ratio, such as a step value of 10 A. By continuously optimizing and adjusting the initial axial position of the transverse magnetic field scanning coil and the first initial current amplitude of the cosine alternating current, the maximum power density of the collector can be brought to the lowest state.

[0069] According to an embodiment of the present disclosure, the initial axial position of the longitudinal magnetic field scanning coil and the second initial current amplitude of the direct current can be adjusted to increase the diffusion area of ​​the waste electron beam, so that the maximum power density of the collector is reduced. Specifically, the initial axial position of the longitudinal magnetic field scanning coil can be initially at 1000 mm, and gradually increase at a third preset ratio, such as a step value of 10 mm, and the second initial current amplitude can be initially at 100 A, and gradually increase at a fourth preset ratio, such as a step value of 10 A. By continuously optimizing and adjusting the initial axial position of the longitudinal magnetic field scanning coil and the second initial current amplitude of the direct current, the maximum power density of the collector can be brought to the lowest state.

[0070] According to an embodiment of the present disclosure, the second preset condition may be a condition when the maximum power density of the collector reaches the lowest state. If at least one of the initial axial position of the transverse magnetic field scanning coil, the initial axial position of the longitudinal magnetic field scanning coil, the initial current amplitude of the cosine alternating current, and the initial current amplitude of the direct current is adjusted, the maximum power density of the collector will be increased, and the above parameters cannot be adjusted at this time. When the above parameters do not need to be adjusted, it can be confirmed that the second preset condition is met.

[0071] Figure 6 The wall power density distribution diagram of the multi-stage buck collector according to the embodiment of the present disclosure is schematically shown.

[0072] like Figure 6 As shown, by introducing a transverse magnetic field scanning system in a multi-stage step-down collector, the maximum power density of the collector wall can be greatly reduced to 392 W / cm2 for a 2 MW power output gyrotron when the center position of the transverse magnetic field scanning coil is 1200 mm in the axial direction (the distance between the center position of the coil and the step-down collector) and 330 mm in the lateral direction (the inner diameter of the coil), the lateral dimension is 30 mm (the thickness of the coil along the radial direction), the axial dimension is 22 mm (the thickness of the coil along the symmetry axis of the coil), and the excitation current amplitude is 500 A; the center position of the longitudinal magnetic field scanning coil is 1350 mm in the axial direction and 320 mm in the lateral direction, the lateral dimension is 20 mm, the axial dimension is 30 mm, and the excitation current amplitude is 300 A. 2 The above parameter settings can effectively improve the power capacity of the collector, thereby ensuring the safe, reliable and stable operation of the gyrotron.

[0073] According to the embodiments of the present disclosure, a comprehensive evaluation is performed on the three indicators of the multi-stage step-down collector, namely, the collection efficiency, the reflux rate and the maximum power density. By optimizing and adjusting the electrode size, voltage drop, tilt parameters of the collector, and the position and excitation current amplitude of the transverse magnetic field scanning system, the collection efficiency, the reflux rate and the maximum power density are optimized, thereby realizing the recovery and power dissipation of the waste electron injection energy generated by the 170GHz megawatt-class gyrotron.

[0074] According to the embodiments of the present disclosure, in order to reduce the maximum power density value of the collector wall, the waste electron beam diffusion area can be increased by appropriately increasing the electrode size, thereby reducing the maximum power density. However, this will also increase the radial size of the collector.

[0075] According to an embodiment of the present disclosure, in order to suppress secondary electron emission, a material with a low secondary electron emission coefficient may be coated on the collector wall, but this will increase the design cost.

[0076] It should be noted that, unless it is explicitly stated that there is a sequence of execution between different operations shown in the flowchart in the embodiments of the present disclosure, or there is a sequence of execution between different operations in technical implementation, otherwise, the execution order of multiple operations may not be prioritized, and multiple operations may also be executed simultaneously.

[0077] The flow charts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0078] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways without departing from the spirit and teachings of the present disclosure. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0079] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A method for determining parameters of a multi-stage step-down collector, comprising: Determining the initial electrode size of each of the multiple electrodes of the multi-stage buck collector according to the performance evaluation index of the gyrotron and the process evaluation index of the multi-stage buck collector, wherein the performance evaluation index includes the power generated by the gyrotron, and the multi-stage buck collector is used to dissipate the power generated by the gyrotron; determining an initial voltage drop of each of the plurality of electrodes according to the energy distribution of the waste electron beam generated in the gyrotron; Determining an initial tilt parameter of at least one electrode among the plurality of electrodes according to an arrangement of the plurality of electrodes; Adjusting the initial electrode size, the initial voltage drop and the initial tilt parameter until the collection efficiency and the reflux rate of the multi-stage step-down collector meet a first preset condition; The electrode size, voltage drop and tilt parameters obtained when the first preset condition is met are determined as the target electrode size, target voltage drop and target tilt parameters of the multi-stage buck collector.

2. The method according to claim 1, further comprising: Adding a magnetic field around the multi-stage step-down collector and determining initial magnetic field parameters; Adjusting the initial magnetic field parameters until the maximum power density of the multi-stage buck collector meets a second preset condition; The magnetic field parameters obtained when the second preset condition is met are determined as the target magnetic field parameters of the multi-stage step-down collector.

3. The method according to claim 1, wherein: The initial tilt parameters include an initial tilt angle and an initial axial length; The adjusting the initial electrode size, the initial voltage drop and the initial tilt parameter until the collection efficiency and the reflux rate of the multi-stage step-down collector meet a first preset condition includes: The initial tilt angle is set to a fixed value, and the initial axial length is adjusted according to a first preset ratio to obtain a target axial length; Adjusting the initial tilt angle according to the target axial length according to a second preset ratio until the collection efficiency and the reflux rate of the multi-stage step-down collector meet the first preset condition; The tilt angle obtained when the first preset condition is met is determined as the target tilt angle of the multi-stage step-down collector.

4. The method according to claim 1, wherein: The step of determining the initial voltage drop of each electrode of the plurality of electrodes according to the energy distribution of the waste electron beam generated in the gyrotron comprises: determining a voltage drop difference between every two adjacent electrodes in the plurality of electrodes according to a range of the waste electron beam energy distribution; An initial voltage drop of each of the plurality of electrodes is determined based on the voltage drop difference.

5. The method according to claim 2, wherein: The magnetic field includes a first magnetic field generated by a first direction spiral coil and a second magnetic field generated by a second direction spiral coil; Adding a magnetic field around the multi-stage step-down collector includes: Passing cosine alternating current into the spiral coil in the first direction to obtain the first magnetic field that rotates dynamically; Direct current is supplied to the spiral coil in the second direction to obtain the second magnetic field which rotates dynamically.

6. The method according to claim 5, wherein: The magnetic field parameters include: a first initial axial position of the first direction spiral coil, a second initial axial position of the second direction spiral coil, a first initial current amplitude of the cosine alternating current, and a second initial current amplitude of the direct current.

7. The method according to claim 6, wherein: The adjusting the initial magnetic field parameters until the maximum power density of the multi-stage buck collector meets the second preset condition includes: adjusting the first initial axial position according to a third preset ratio, and adjusting the first initial current amplitude according to a fourth preset ratio, until the maximum power density of the multi-stage buck collector meets a second preset condition; The first axial position and the first current amplitude obtained when the second preset condition is satisfied are determined as the first target axial position and the first target current amplitude of the multi-stage buck collector.

8. The method according to claim 6, wherein: The adjusting the initial magnetic field parameters until the maximum power density of the multi-stage buck collector meets a second preset condition further includes: adjusting the second initial axial position according to a third preset ratio, and adjusting the second initial current amplitude according to a fourth preset ratio, until the maximum power density of the multi-stage buck collector meets a second preset condition; The second axial position and the second current amplitude obtained when the second preset condition is satisfied are determined as the second target axial position and the second target current amplitude of the multi-stage buck collector.

9. A multi-stage step-down collector, comprising: A plurality of electrodes are arranged inside the multi-stage step-down collector, at least one of the plurality of electrodes is arranged tilted, wherein the parameters of each of the plurality of electrodes include a target electrode size, a target tilt parameter, and a target voltage drop; A spiral coil, arranged around the multi-stage step-down collector, for generating a magnetic field; The target electrode size, the target tilt parameter, the target voltage drop and the magnetic field parameters of the magnetic field are determined by the method of any one of claims 2, 5 to 8.

10. The multi-stage step-down collector according to claim 9, wherein: The multiple electrodes include a first electrode, a second electrode, a third electrode and a fourth electrode; the first electrode, the second electrode, the third electrode and the fourth electrode are arranged in sequence, and the fourth electrode is an end electrode of a multi-stage step-down collector and is arranged obliquely.

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