JPH10269957A - Gyrotron device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize highly efficient oscillation without increasing the cost of a gyrotron, and provide a gyrotron capable of easily operating. SOLUTION: A gyrotron device 300 consists an electron gun 1, a cavity resonator 6, a collector 7, an output window 8, a main magnetic field generating electromagnet 11 for generating a magnetic field in the vicinity of the cavity resonator 6, and inclined magnetic field generating electromagnets 20a, 20b. The inclined magnetic field generating electromagnets 20a, 20b, when the device 300 oscillates the specified frequency, generate a magnetic field of 10% or less of the axial direction flux density in the central part of the cavity resonator 6, and desirable axial direction magnetic field distribution is generated on the inside and in the vicinity of the cavity resonator 6 by the magnetic field.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gyrotron apparatus for generating microwaves or millimeter waves by utilizing an electron cyclotron resonance maser effect between an electron beam and a high-frequency electromagnetic field in the eigenmode of a cavity resonator. It is.

[0002]

2. Description of the Related Art A gyrotron device utilizing an electron cyclotron resonance maser interaction between an electron beam and a high-frequency electromagnetic field in the eigenmode of a cavity resonator is disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 56-102045. I have. FIG. 12 schematically shows such a conventional gyrotron device. FIG. 12 is a cross-sectional view showing a gyrotron device using a conventional tripolar electron gun. In the figure, 101 is an electron gun for extracting an electron beam 109, 102 is a cathode, and 1 is a cathode.
03 is an electron emission portion on the cathode 102, 104 is a first anode, and 105 is a second anode, which is usually a ground potential. Reference numeral 106 denotes a cavity resonator in which an electron beam 109 and a high-frequency electromagnetic field interact with each other in a resonant manner to generate a high frequency 110; 107, a collector for recovering the electron beam 109 after the interaction; 108, an output for extracting the high frequency 110 The gyrotron device 300 is a window.
01, cavity resonator 106, collector 107, output window 10
Gyrotron 200 composed of an electron beam 10 and the like
9 is provided with a main magnetic field generating electromagnet 111 and an electron gun magnetic field generating electromagnet 112 for generating a magnetic field in the axial direction of the gyrotron 200 in order to give a turning motion. As the electromagnet 111 for generating the main magnetic field and the electromagnet 112 for generating the magnetic field of the electron gun, an electromagnet using a superconductive electromagnet, a normal electroconductive magnet, or both of them is used.

Next, the operation will be described. Electron gun 101
The electron beam 109 emitted from the electron emission portion 103 on the cathode 102 of the
The magnetic field generated by the electron gun magnetic field generating electromagnets 112 is accelerated by an electric field between the electron guns 04 and drifts in the axial direction while rotating. Further, the electron beam 109 is compressed by the strong magnetic field generated by the main magnetic field generating electromagnet 111, and the electrons increase their speed in the direction perpendicular to the magnetic field and decrease the speed in the direction parallel to the magnetic field. Enters the cavity resonator 106. The electrons that are cyclotron-moving by the axial magnetic field generated by the main magnetic field generating electromagnet 111 interact with the high-frequency electromagnetic field of the eigenmode in the cavity resonator 106 and the cyclotron resonance maser, and the velocity in the direction perpendicular to the magnetic field of the electrons. Some of the energy from the components is converted to high frequency energy. The electron beam 109 that has completed the interaction with the cavity resonator 106 is collected by the collector 107 and is
The high frequency 110 excited in 6 passes through the output window 108 and is extracted to the outside.

In the cavity resonator 106, the electron beam 1
09 is efficiently converted to high-frequency energy when the following equation is satisfied. ω−k _z v _z ≒> sΩ _c (1) where ω is the resonance angular frequency of the eigenmode electromagnetic field in the cavity resonator 106, k _z is the axial wavenumber of the eigenmode,
v _z is the axial velocity of the electron, s is the harmonic order, Ω _c is the cyclotron angular frequency of the electron considering relativistic effects, 効果
> Indicates the Esuomega _c be slightly smaller than the ω-k _z v _z.

[0005] This Ω _c represents the charge of the electron as e (absolute value),
When the axial magnetic flux density in the cavity resonator 106 is B, the relativistic coefficient is γ, and the static mass of the electrons is m ₀ , the following equation is given. Ω _c = eB / γm ₀ (2) As can be seen from the equation (1), the energy of the electron beam 109 is efficiently converted into high-frequency energy and a strong electromagnetic wave is generated on the right side of the equation (1). Is slightly smaller than the left side.

Also, the acceleration voltage of the electron beam 109 is set to V _b
[kV], the relativistic coefficient γ is given by the following equation. γ = 1 + V _b / 511 (3) Therefore, from equation (3), γ changes when the acceleration voltage V _b of the electron beam 109 is changed. Therefore, in order to satisfy equation (1), axis It can be seen that the directional magnetic flux density B needs to be adjusted.

As described above, in the gyrotron device, the magnetic field plays an essential role, and it is important to accurately adjust the magnetic field in order to operate the gyrotron device efficiently.

Next, another conventional example will be described. FIG.
FIG. 1 is a sectional view showing a gyrotron device using a conventional bipolar electron gun. In FIG. 12 described above, the electron gun 101 of the gyrotron 200 is a three-pole type electron gun including a cathode 102, a first anode 104, and a second anode 105. In FIG. Type electron guns are used. Typically, in a two-pole electron gun, the anode 114 is at ground potential. A gyrotron device using a two-electron electron gun is described in, for example, "Radiophysics. Quantum Elec," magazine: Radiophysics Quantum Electronics (vol. 18, No. 2, 1975, p. 204).
tron. (Vol. 18, No. 2, 1975, P. 2)
04)). The three-pole type electron gun shown in FIG.
3 also has a hollow electron beam 109.
And the operation of operating the gyrotron 200 is the same.

[0009]

Since the conventional gyrotron device is configured as described above, the electron beam 1
09 according to the accelerating voltage of 09 or the electron beam current.
The magnetic flux density must be adjusted to the optimum value by adjusting the current flowing to 1 etc., and it takes much time and effort.
There were issues such as high operating costs. That is,
As can be seen from Equations (1) and (2), in order to obtain high-frequency oscillation, it is necessary to generate a high magnetic field in the cavity resonator 106. For example, fundamental wave oscillation (s = 1) In order to obtain an oscillation at a frequency of 28 GHz, a magnetic field of about 1 T was required.

On the other hand, in order to reduce the operation cost of the gyrotron device, it is effective to increase the oscillation efficiency of the gyrotron.
It has been theoretically known that if the magnetic flux density in the axial direction in 6 has an appropriate distribution, the efficiency will increase. For example, the magazine “IEE Transactions on Microwave Theory and Technics”
volume. Emtyty Hyphen 28, 4th, 1st
980, p. 318 (IEEE Transact)
ions on Microwave Theory
and Techniques Vol. MTT-2
8, No. 4, 1980, p. 318) shows by computer simulation that the efficiency is improved by giving a gradient of about 10% to the axial magnetic flux density at the entrance and exit of the cavity resonator. However, FIG. 12 and FIG.
In the gyrotron device using the electromagnet shown in FIG. 3, there is a problem that it is practically difficult to provide a magnetic flux density gradient of about 10% in the cavity resonator 106 of the gyrotron. As mentioned above, in the gyrotron,
Due to the principle of operation, a high magnetic field is required in the cavity resonator 106, so a considerably large electromagnet is used. In general, a gyrotron operates with a substantially flat distribution of the axial magnetic flux density in the cavity resonator 106. Have been. Therefore, in order to provide a magnetic flux density gradient of about 10% in the range of the cavity resonator 106 having a length several times the free space wavelength with respect to the oscillation frequency of the gyrotron, FIG. 2
A different current may be applied to each of the main magnetic field generating electromagnets 111 (the number is not necessarily two, and may be one or three or more as long as a required main magnetic field can be generated), or the number of windings may be different. And shape. However, the former has a problem in that a plurality of excitation power supplies are required and the apparatus becomes costly, and the latter has a problem that it is difficult to finely adjust the gradient magnetic field distribution. Further, the main magnetic field generating electromagnet 111
This situation does not change even if the number is three or more.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. A gyrotron device that realizes high-efficiency oscillation without increasing the cost of the gyrotron device and that can easily operate the gyrotron device is provided. The purpose is to gain.

According to the present invention, a large gradient magnetic field can be generated in a relatively short section in a cavity resonator.
It is an object of the present invention to obtain a gyrotron device that can increase the efficiency of gyrotron oscillation.

A further object of the present invention is to provide a gyrotron apparatus which can select an optimum gradient magnetic field distribution in accordance with the acceleration voltage and current of the electron beam in the gyrotron, and the oscillation output, and has good operability. And

Another object of the present invention is to provide a gyrotron device which can safely apply a gradient magnetic field to the cavity resonator without fear of electric shock and can increase the oscillation efficiency of the gyrotron.

[0015]

According to a first aspect of the present invention, there is provided a gyrotron apparatus comprising: an electron gun;
A cavity resonator, a collector, and an output window; the magnetic field generating means includes a main magnetic field generating electromagnet and a gradient magnetic field generating electromagnet that generate a magnetic field near the cavity resonator; The generating electromagnet generates a magnetic field of 10% or less of the axial magnetic flux density at the center of the cavity resonator when the gyrotron device is oscillating at a predetermined frequency, and generates the magnetic field by the magnetic field. This is to generate an axial magnetic field having a desired distribution in and around the cavity resonator.

In a gyrotron apparatus according to a second aspect of the present invention, the gradient magnetic field generating electromagnet includes two or more electromagnets wound in the same direction, and the direction of the axial magnetic field generated by the electromagnet wound in the same direction. Are arranged so as to be opposite to each other.

In a gyrotron apparatus according to a third aspect of the present invention, the electromagnet for generating a gradient magnetic field includes at least one right-handed electromagnet and at least one left-handed electromagnet, and the right-handed electromagnet and the left-handed electromagnet are generated. The directions of the axial magnetic fields are opposite to each other.

A gyrotron device according to a fourth aspect of the present invention is configured such that the gyrotron including the electron gun, the cavity resonator, the collector, and the output window performs a double harmonic oscillation operation. It was done.

In a gyrotron apparatus according to a fifth aspect of the present invention, the electromagnet for generating a gradient magnetic field has one or more intermediate taps in addition to the input / output terminals.

In the gyrotron apparatus according to the present invention, an electrical insulator withstanding a voltage of at least 1 kV is provided between the electromagnet for generating a gradient magnetic field and the gyrotron tube.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a sectional view showing a gyrotron device according to Embodiment 1 of the present invention.
Denotes an electron gun for extracting an electron beam 9, 2 denotes a cathode, 3 denotes an electron emission portion on the cathode 2, 4 denotes a first anode, and 5 denotes a second anode. Numeral 6 denotes a cavity which generates a high frequency 10 by an interaction between the electron beam 9 and the high frequency electromagnetic field in a resonant manner, and is formed in a cylindrical shape.
Reference numeral 7 denotes a collector for collecting the electron beam 9 after the interaction, and reference numeral 8 denotes an output window for extracting the high frequency 10. Reference numeral 200 denotes the electron gun 1, the cavity resonator 6, the collector 7, and the output window 8.
A gyrotron consisting of 11 is electron beam 9
An electromagnet for generating a main magnetic field for generating a magnetic field in the axial direction of the gyrotron 200 to give a turning motion to the gyrotron 200, and an electromagnet 12 for generating a magnetic field of an electron gun. 300 is gyrotron 20
This is a gyrotron device composed of an electromagnet 11 for generating a main magnetic field and an electromagnet 12 for generating a magnetic field of an electron gun.
Reference numerals 20a and 20b denote electromagnets for generating a gradient magnetic field for increasing the magnetic flux density in the axial direction from the electron gun 1 side to the collector 7 side and applying a gradient magnetic field in the cavity resonator 6. Reference numeral 30 denotes a coil bobbin of the electromagnets 20a and 20b for generating a gradient magnetic field.
It is formed using a material having high thermal conductivity such as aluminum. Such a material is used for the coil form 3
This is for increasing the cooling effect of the gradient magnetic field generating electromagnets 20a and 20b by bringing 0 into contact with the outer wall near the cavity resonator 6. Therefore, as long as such a cooling effect can be ensured, the coil winding frame 30 may be made of aluminum, anodized aluminum, or resin. Further, in order to improve the thermal conductivity at the contact portion with the outer wall near the cavity 6, the grease is applied to the inner surface of the coil winding frame 30 and the outer wall surface of the gyrotron 200 to which the coil winding frame 30 is mounted. Etc. may be applied. The coil winding frame 30 can be fixed by cutting a screw on the outer wall of the gyrotron 200 and fixing it with a bolt, or by fixing the outer wall with a bolt so as not to be displaced.

FIG. 2 is a graph showing an axial magnetic flux density Bz distribution in which a gradient magnetic field is applied near the cavity resonator.
In the figure, _Bin denotes the electron gun 1 in the cylindrical portion of the cavity resonator 6.
The axial magnetic flux density at the side end, ΔB is the difference between the axial magnetic flux density at the collector 7 side end of the cylindrical portion of the cavity resonator 6 and the electron gun 1 side end. According to theoretical calculations, Gyrotron 200
Optimal value of the magnitude △ B / B _in the gradient magnetic field required to improve the oscillation efficiency of, it depends on the output or the like of the acceleration voltage and a gyrotron 200 of the electron beam 9, at most 10
% Or less.

Next, the operation will be described. The electron beam 9 emitted from the electron emitting portion 3 on the cathode of the electron gun 1
Is accelerated by an electric field between the cathode 2 and the first anode 4 and drifts in the axial direction while rotating, due to the magnetic field generated by the electromagnet 12 for generating an electron gun magnetic field. Further, the electron beam 9 is compressed by the strong magnetic field generated by the electromagnet 11 for generating the main magnetic field, and the electrons increase in the speed in the direction perpendicular to the magnetic field and decrease in the speed in the parallel direction. Enter 6. Electrons that are cyclotron-moving due to the axial magnetic field generated by the main magnetic field generating electromagnet 11 interact with a high-frequency electromagnetic field of the eigenmode in the cavity resonator 6 and a cyclotron resonance maser, and the velocity in the direction perpendicular to the magnetic field of the electrons. Some of the energy from the components is converted to high frequency energy. Assuming that the velocity at which the electrons reach the entrance of the cavity resonator 6 is v, the relativistic coefficient γ is given by the following equation. γ = {1− (v / c) ² } ^−1/2 (4) where c is the speed of light, and γ in equation (4) is another expression of γ in equation (3) described above. It is. As the electrons interact with the high-frequency electromagnetic field in the cavity 6 and lose their energy, the speed of the electrons decreases, and it can be seen from equation (4) that γ also decreases. That is, the mass of electrons decreases. Therefore, from the equation (2), the electron cyclotron angular frequency Ω _c considering the relativistic effect is obtained.
Becomes larger for electrons losing energy, and does not satisfy equation (1) for such electrons. Such electrons no longer convert their kinetic energy into high-frequency energy, but instead receive energy from a high-frequency electromagnetic field and are accelerated. Such a phenomenon is called an “electron re-acceleration phenomenon” and lowers the oscillation efficiency of the gyrotron 200, and this phenomenon limits the oscillation efficiency.

However, as described above, it is theoretically known that by applying a gradient magnetic field to the cavity resonator 6, the oscillation efficiency can be improved as compared with the case where there is no gradient magnetic field. FIG. 3 is a graph showing the relationship between the axial distance Z of the cavity resonator and the average kinetic energy of electrons. In the figure, the horizontal axis Z indicates the axial distance of the cavity resonator 6, where Z = 0 is the entrance end of the cavity resonator 6, Z = 10
0 mm corresponds to the outlet end. The vertical axis represents the average kinetic energy of some electrons traveling while interacting with the high-frequency electromagnetic field in the cavity 6 and is normalized by the kinetic energy at the entrance of the cavity 6. Further, this calculation example relates to a gyrotron having an oscillation frequency of 28 GHz and an oscillation mode of TE02 mode, and is a result when the acceleration voltage of the electron beam is _Vb = 21 kV and the output is 11 kW. When the magnetic field is flat, that is, △ B / B _in
In the case of = 0%, the average kinetic energy of the electrons increases from above about Z = 80 mm, and it can be seen that the electron reacceleration phenomenon occurs.

On the other hand, when ΔB / B _in = 1.5%, that is, the axial magnetic flux density at the exit end of the cavity resonator 6 is 1.times. The axial magnetic flux density B _in at the entrance end. When a gradient magnetic field larger than 5% is applied, the average kinetic energy of electrons is reduced even after Z exceeds 80 mm, and the oscillation efficiency is improved by avoiding the re-acceleration phenomenon of electrons as a whole. You can see that. As can be seen from equation (2), this can be realized by positively increasing the cyclotron angular frequency of the electrons by applying a gradient magnetic field, and moving the electrons out of the frequency range in which the electrons are reaccelerated. In this calculation example, △ B / B _in = 1.5% is the optimum gradient magnetic field.
There is an optimum gradient magnetic field depending on the acceleration voltage and output of the electron beam. However, in any case, the oscillation efficiency of the gyrotron can be improved by a gradient magnetic field of about 10% or less at the maximum.

In a conventional gyrotron device without the gradient magnetic field generating electromagnets 20a and 20b, it is difficult to generate a local axial gradient magnetic field distribution in the cavity resonator portion. As described above, the oscillation frequency of the gyrotron 200 is an integral multiple of the electron cyclotron frequency with respect to the axial magnetic field applied to the cavity resonator 6,
In order to obtain a high frequency oscillation, a high magnetic field is required. Accordingly, since the main magnetic field generating electromagnet 11 is generally composed of a plurality of considerably large electromagnets, it is difficult to generate such a local gradient magnetic field using the main magnetic field generating electromagnet 11. If a gradient magnetic field is to be generated, (a) the magnitude of the generated magnetic field for the same current is changed by changing the number of turns of the plurality of electromagnets, and (b) the arrangement of the plurality of electromagnets is equally spaced. (C) Appropriate currents are supplied from different power supplies without supplying the same current to each electromagnet. However, since the length of the cavity 6 is about several times to about 10 times the free space wavelength of the electromagnetic wave with respect to the oscillation frequency of the gyrotron 200, for example, when performing 28 GHz oscillation, 50 to 10
The length is about 0 mm, and the cavity resonator 6 length becomes shorter as the oscillation frequency becomes higher. Therefore, it is difficult to generate a local gradient magnetic field in such a short section with a large electromagnet. Further, since the magnetic field generated by these main magnetic field generating electromagnets 11 also affects the electron gun 1, it changes the acceleration voltage and beam current of the electron beam 9 for operating the gyrotron 200. Each time, it is necessary to adjust not only the exciting current of the main magnetic field generating electromagnet 11 but also the exciting current of the electron gun magnetic field generating electromagnet 12, and the operation of the gyrotron 200 becomes complicated.

On the other hand, the electromagnets 20a and 20b for generating a gradient magnetic field according to the first embodiment have the cavity resonator 6 at the maximum.
A small electromagnet, which only needs to generate about 10% of the magnetic flux density near the center of the cavity, is used, and an axial gradient magnetic field can be easily generated in the cavity resonator 6 and its magnetic field can be increased. Does not affect the first part of the electron gun, so that the magnetic field can be easily adjusted in operation of the gyrotron 200.

As described above, according to the first embodiment, the provision of the small gradient magnetic field generating electromagnets 20a and 20b facilitates the generation of the axial gradient magnetic field in the cavity resonator 6. And the magnetic field is
Since there is no influence on the section, high-efficiency oscillation can be achieved, and the operability thereof can be easily obtained.

In the first embodiment, the number of the electromagnets 20a and 20b for generating the gradient magnetic field is described as two. However, if ΔB in FIG. It is possible to apply a gradient magnetic field to the resonator 6 part,
If that's enough, that's fine, of course.

Embodiment 2 FIG. FIG. 4 is a sectional view showing a gyrotron device according to Embodiment 2 of the present invention. In the figure, reference numeral 1 denotes a bipolar electron gun, which is composed of a cathode 2 and an anode 14. The electron gun 1 according to the first embodiment includes a cathode 2, a first anode 4, and a second anode 4.
Although this is an electron gun called a three-pole electron gun including the anode 5, in the second embodiment, it is configured as a gyrotron 200 using a two-pole electron gun as shown in FIG. The operation is almost the same as that of the first embodiment, and the description is omitted.

As described above, according to the second embodiment, the bipolar electron gun 1 is composed of the cathode 2 and the anode 14 and the second anode 5 Anode 4 which needs to be given a negative potential with respect to
Since there is no such effect, an effect that a simple structure can be obtained is obtained. In addition, the power supply for accelerating the electron beam does not need to consider the potential applied to the first anode 4, so that the effect of simplifying the structure can be obtained.

The triode type electron gun 1 has an advantage that the oscillation of the gyrotron 200 can be controlled by adjusting the potential of the first anode 4. However, each of the two-pole type electron gun 1 and the three-pole type electron gun 1 is also similar in that it extracts an eigenmode high-frequency electromagnetic field and an electron beam 9 which performs a cyclotron resonance maser action in the cavity resonator 6. Work. Therefore, in the following embodiment, even when only the gyrotron 200 using the three-pole electron gun 1 is described, the same can be said for the gyrotron 200 using the two-pole electron gun 1, Conversely, even when only the gyrotron 200 using the two-pole electron gun 1 is described, the same can be said for the gyrotron 200 using the three-pole electron gun 1.

Embodiment 3 FIG. 5 is a sectional view showing a gyrotron device according to Embodiment 3 of the present invention. In the figure, reference numerals 21a and 21b denote gradient magnetic fields for generating a gradient magnetic field with respect to an axial magnetic flux density in a cavity resonator 6 portion. The outer diameter of the gyrotron 200 in the vicinity of the cavity resonator 6 is slightly reduced, and is wound closely. The electromagnets 21a and 21b for generating gradient magnetic fields
May be attached as it is without reducing the outer diameter near the cavity resonator 6. The operation is the same as that of the first embodiment, and the description is omitted.

As described above, according to the third embodiment, since the inner diameters of the gradient magnetic field generating electromagnets 21a and 21b can be reduced, the power consumption for generating the same magnetic field can be reduced.

Embodiment 4 FIG. FIG. 6 is a side view (a) showing an electromagnet for generating a gradient magnetic field of a gyrotron apparatus according to Embodiment 4 of the present invention, and a graph (b) showing the distribution of the axial magnetic flux density. 22b is an electromagnet for generating a gradient magnetic field (an electromagnet wound in the same direction) formed by winding a coil of the same specification around the winding frame 31 in the same direction,
Reference numerals 40 and 41 denote respective electromagnets 22a for generating a gradient magnetic field.
This is a DC power supply that supplies current to 22b. Other configurations are
This is the same as in the first embodiment.

Next, the operation will be described. Since the coils of the gradient magnetic field generating electromagnets 22a and 22b are wound in the same direction with respect to the bobbin 31, when the DC power supplies 40 and 41 are connected as shown in FIG. The direction of the flowing current is reversed, and the generated axial magnetic flux density (axial magnetic field) Bz is also reversed. Accordingly, the distribution of the axial magnetic flux density Bz generated by the gradient magnetic field generating electromagnets 22a and 22b is as shown in FIG.
It is easy to generate a large gradient magnetic field in a relatively short section across point C where the magnetic flux density becomes zero in the figure, and the generation of a gradient magnetic field applied to the cavity resonator 6 for improving the efficiency of gyrotron oscillation. Suitable for.

As described above, according to the fourth embodiment, a large gradient magnetic field can be generated in a relatively short section in the cavity resonator 6, and the effect of increasing the efficiency of gyrotron oscillation can be achieved. can get.

In the fourth embodiment, since the coils of the gradient magnetic field generating electromagnets 22a and 22b have the same specifications and the same current, the Bz distribution is symmetrical with respect to the point C. However, it is not always necessary. That is, in order to generate an optimal Bz distribution, the number of turns of the coil, the coil length, and the like may be different, and the current flowing may be different. In that case, as shown in FIG. 7, the Bz distribution is an asymmetric distribution with the point C interposed therebetween. FIG. 7 is a graph showing the distribution of the axial magnetic flux density when different electromagnets for generating a gradient magnetic field are used. Also, paying attention to the connection between the DC power supplies 40 and 41 and the coil, by connecting the gradient field generating electromagnets 22a and 22b of FIG. 6A to one power supply in parallel, as shown in FIG. 6B. It is possible to obtain a suitable Bz distribution. Further, in FIG. 6A, although the number of the electromagnets for generating the gradient magnetic field is two, the number is not necessarily two, and three or more electromagnets may be used to obtain an optimum Bz distribution.

Embodiment 5 FIG. 8 is a side view (a) showing a gradient magnetic field generating electromagnet of a gyrotron apparatus according to Embodiment 5 of the present invention, and a graph (b) showing its axial magnetic flux density distribution. 23b is a coil of the same specification (a right-handed electromagnet and a left-handed electromagnet)
And an electromagnet for generating a gradient magnetic field is wound around the winding frame 31 in the opposite direction. Other configurations are the same as those in the first embodiment.

Next, the operation will be described. Since the coils of the gradient magnetic field generating electromagnets 23a and 23b are wound in the opposite direction with respect to the bobbin 31, as shown in FIG.
Each of the electromagnets 23 for generating a gradient magnetic field even if wound continuously.
The directions of the magnetic flux densities Bz in the axial direction where the a and 23b are generated are opposite, and the Bz distribution generated by the two is shown in FIG.
The result is as shown in FIG. Even with such electromagnets 23a and 23b for generating a gradient magnetic field, it is easy to generate a large gradient magnetic field in a relatively short section with respect to a point C where the magnetic flux density becomes zero in the figure, and high efficiency of gyrotron oscillation is obtained. It is suitable for generating a gradient magnetic field to be applied to the cavity resonator 6 for the purpose.

As described above, according to the fifth embodiment, a large gradient magnetic field can be generated in a relatively short section in the cavity resonator 6, and the effect of increasing the efficiency of gyrotron oscillation can be achieved. can get.

In the fifth embodiment, two coils of the electromagnets 23a and 23b for generating the gradient magnetic field have been described as being used with the same specifications. However, the coils need not always have the same specifications. In order to obtain the above, the number of turns and the coil length may be different, or three or more electromagnets for generating a gradient magnetic field may be used.

Embodiment 6 FIG. FIG. 9 is a sectional view showing a gyrotron device according to Embodiment 6 of the present invention. In FIG. 9, reference numeral 6 denotes a cavity resonator, which has a cavity length longer than that of the gyrotron 200 operating in a fundamental wave. It is designed to be longer to increase the time during which the electron beam interacts with the harmonic electromagnetic field. The other configuration is the same as that shown in FIG. 4 of the second embodiment, and the description is omitted.

Next, the operation will be described. The gyrotron 200 operates at double harmonic oscillation. Here, the operation of the double harmonic oscillation is an oscillation operation in the case where s in the above equation (1) is s = 2, and can be understood from the equations (1) and (2). In order to obtain the same frequency of oscillation, the axial magnetic flux density B in the cavity 6
May be about の of the case of the fundamental wave oscillation of s = 1. Therefore, the electromagnet 11 for generating the main magnetic field and its excitation power source are smaller than the gyrotron device 300 of the fundamental wave oscillation. However, the interaction between the electron beam and the high-frequency electromagnetic field in the cavity resonator 6 becomes weaker as the harmonic order s increases, and the oscillation efficiency of the gyrotron 200 also decreases. Therefore, in the gyrotron 200 of the double harmonic operation, the length of the cavity 6 is made longer than that of the gyrotron 200 of the fundamental wave operation, and the time during which the electron beam and the harmonic electromagnetic field interact is longer. It is designed to be.

For the gyrotron 200 having such a double harmonic operation, a method of applying a gradient magnetic field in the cavity resonator 6 to improve the oscillation efficiency is particularly effective. The reason is that the axial magnetic flux density required to obtain the same frequency oscillation is about の of that of the fundamental wave oscillation, so that even if the same ΔB / B _in is applied, the magnitude of the gradient magnetic field is large. This is because ΔB may be small, and thus the gradient magnetic field generating electromagnets 20a and 20b can be reduced in size, or the current flowing through the gradient magnetic field generating electromagnets 20a and 20b can be small. Furthermore, since the length of the cavity resonator 6 is longer than that of the gyrotron 200 operating in the fundamental wave, there is an advantage that an appropriate gradient magnetic field distribution is easily generated.

As described above, according to the sixth embodiment, there is an effect that the gyrotron can be configured to be more compact than a gyrotron device of the fundamental wave oscillation operation while increasing the efficiency of the gyrotron oscillation. In other words, for the gyrotron 200 of the double harmonic operation in which the cavity resonator 6 has a longer length than the gyrotron 200 of the fundamental wave operation, the cavity resonator 6
A method of improving the oscillation efficiency of the gyrotron 200 by applying a gradient magnetic field to the inside is effective, and moreover, it is twice as large as combining an electromagnet which easily generates a flat magnetic field over a long distance and electromagnets 20a and 20b for generating a gradient magnetic field. An effect that is a particularly effective means for the gyrotron device 200 of the harmonic operation is obtained.

In the gyrotron operating at a higher harmonic than the third harmonic, the interaction between the electron beam and the high-frequency electromagnetic field in the cavity is weakened. It is difficult to do so, and high efficiency by the gradient magnetic field cannot be expected very much.

Embodiment 7 FIG. FIG. 10 is a side view (a) showing an electromagnet for generating a gradient magnetic field of a gyrotron apparatus according to Embodiment 7 of the present invention, and a graph (b) showing the distribution of the axial magnetic flux density. An electromagnet for generating a gradient magnetic field.
5b, 25c and 25d come out. 25a and 25e are coil ends (input / output ends) at both ends of the gradient magnetic field generating electromagnet 24. 24a, 24b, 24c, 24d
Are coils (magnets for generating a gradient magnetic field) located between 25a and 25b, between 25b and 25c, between 25c and 25d, and between 25d and 25e, respectively. Reference numeral 32 denotes a winding frame of the electromagnet 24 for generating a gradient magnetic field.

Next, the operation will be described. When such a gradient magnetic field electromagnet 24 is used, by selecting an appropriate intermediate tap and considering the direction of the flowing current, the axial magnetic flux density of various axial distributions can be increased in order to increase the efficiency of gyrotron oscillation. Bz can be generated. FIG.
FIG. 2B shows an example of this. In the figure, the gradient magnetic field # 1 is represented by 2 having both ends of the coils 25a and 25c.
The gradient magnetic field distribution in the axial direction is generated by using coils 24c and 24d having both ends of the coils 4a and 24b and the coils 25c and 25e. Gradient magnetic field # 2 is coil 2
This is an axial gradient magnetic field distribution generated using coils 24b and 24c having both ends 5b and 25d and coils 24d having both ends of coils 25d and 25e. By selecting an appropriate intermediate tap as the coil end in this way, the gradient magnetic field distribution in the axial direction and the gradient of the magnetic field can be changed. Therefore, the acceleration voltage of the electron beam 9 in the gyrotron 200, its current, and oscillation output , An optimal gradient magnetic field distribution can be selected.

As described above, according to the seventh embodiment, the axial gradient magnetic field distribution and the gradient of the magnetic field can be changed by selecting an appropriate intermediate tap as the coil end. The optimum gradient magnetic field distribution can be selected according to the acceleration voltage of the electron beam 9 in 200, its current, and the oscillation output, and the effect of improving operability can be obtained.

Embodiment 8 FIG. FIG. 11 is a sectional view showing a gyrotron device according to Embodiment 8 of the present invention.
In the figure, reference numeral 16 denotes a spacer formed of an electrically insulating material such as alumina, which forms a slit 17, and is connected to a gyrotron main body portion 60 as a gyrotron tube (this portion is connected to the anode 14 by a conductor. And have the same electrical potential) and the collector 7 are electrically insulated. The width of this slit 17 is set to １ ／ or less of the wavelength of the high frequency 10 generated by the cavity resonator 6, and the high frequency propagates through the collector 7 without being affected by the high frequency, and the output window 8. Reference numerals 26a and 26b are electromagnets for generating a gradient magnetic field, and reference numeral 35 is a winding frame (electric insulator) made of an insulator such as Teflon for electrically insulating the electromagnets 26a and 26b for generating a gradient magnetic field. Reference numeral 50 denotes an anode power supply for applying a voltage between the cathode 2 and the anode 14, and the voltage is defined as Va. Reference numeral 51 denotes a collector power supply for applying a voltage between the cathode 2 and the collector 7, and the voltage is defined as Vc. The collector 7 is generally grounded.

Next, the operation will be described. Assuming that the relationship between the voltages is Va> Vc (5), the electron beam emitted from the electron-emitting portion 3 on the cathode 2 is accelerated by the voltage Va. After acting, collector 7
The electron experiences a deceleration voltage (Vc-Va) before being collected. The deceleration energy of the electron beam can be considered to be recovered by the collector power supply 51, and the oscillation efficiency of the gyrotron can be increased as a whole. In the gyrotron device according to the embodiment described above,
Although the anode 14 or the second anode 5 of the gyrotron tube was at the ground potential, in the gyrotron device according to the eighth embodiment, as can be seen from FIG.
The anode 14 is higher than the ground potential (Va−Vc>
0), the magnitude of which depends on the accelerating voltage of the electron beam when operating the gyrotron;
About V. Therefore, the gradient magnetic field generating electromagnet 26
a, 26b and the gyrotron main body 60 (anode 1)
4 is higher than the ground potential because the potential is the same as that of the grounding material 4), and the winding frame 35 as an insulator is provided for this purpose.

As described above, according to the eighth embodiment, by providing the winding frame 35 as an electrical insulator, the gradient magnetic field can be safely applied to the cavity resonator 6 without fear of electric shock. And the effect of further increasing the oscillation efficiency of the gyrotron is obtained.

[0054]

As described above, according to the first aspect of the present invention, an electron gun, a magnetic field generating means, a cavity resonator, a collector, and an output window are provided. An electromagnet for generating a main magnetic field and an electromagnet for generating a gradient magnetic field that generates a magnetic field near the cavity resonator, the electromagnet for generating a gradient magnetic field, when the gyrotron device is oscillating at a predetermined frequency, A magnetic field of 10% or less of the axial magnetic flux density at the center of the cavity is generated, and the magnetic field generates an axial magnetic field having a desired distribution inside and near the cavity. With such a configuration, a small gradient magnetic field generating electromagnet can easily generate an axial gradient magnetic field in the cavity resonator portion, and the magnetic field does not affect the electron gun portion. , Realize high efficiency oscillation, One, there is an effect that can be easily operability.

According to the second aspect of the present invention, the electromagnet for generating a gradient magnetic field includes two or more electromagnets wound in the same direction, and the directions of the axial magnetic fields generated by the electromagnets wound in the same direction are opposite to each other. Since it is arranged so as to be oriented in the same direction, it is possible to generate a large gradient magnetic field in a relatively short section in the cavity resonator, which has the effect of increasing the efficiency of gyrotron oscillation. .

According to the third aspect of the present invention, the electromagnet for generating a gradient magnetic field includes at least one right-handed electromagnet and at least one left-handed electromagnet, and the axial direction in which the right-handed electromagnet and the left-handed electromagnet are generated. Since the magnetic fields are arranged so that their directions are opposite to each other, a large gradient magnetic field can be generated in a relatively short section in the cavity resonator,
This has the effect of increasing the efficiency of gyrotron oscillation.

According to the fourth aspect of the present invention, an electron gun,
The gyrotron including the cavity resonator, the collector, and the output window is configured to perform the double harmonic oscillation operation. Therefore, the gyrotron of the fundamental oscillation operation is achieved while increasing the efficiency of the gyrotron oscillation. There is an effect that the device can be configured to be smaller than the tron device.

According to the fifth aspect of the present invention, since the electromagnet for generating a gradient magnetic field is provided with one or more intermediate taps other than the input and output ends, by selecting an appropriate intermediate tap, Since the gradient magnetic field distribution in the axial direction and the gradient of the magnetic field can be changed, the optimal gradient magnetic field distribution can be selected according to the acceleration voltage of the electron beam in the gyrotron, its current, and the oscillation output. It has the effect of improving.

According to the sixth aspect of the present invention, an electrical insulator withstanding a voltage of at least 1 kV is provided between the electromagnet for generating a gradient magnetic field and the gyrotron tube. It is possible to safely apply a gradient magnetic field without fear of electric shock to the device part, which has the effect of increasing the oscillation efficiency of the gyrotron.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a gyrotron device according to Embodiment 1 of the present invention.

FIG. 2 is a graph showing an axial magnetic flux density Bz distribution in which a gradient magnetic field is applied near a cavity resonator.

FIG. 3 is a graph showing a relationship between an axial distance Z of a cavity resonator and an average kinetic energy of electrons.

FIG. 4 is a sectional view showing a gyrotron device according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a gyrotron device according to Embodiment 3 of the present invention.

6A is a side view showing an electromagnet for generating a gradient magnetic field of a gyrotron device according to a fourth embodiment of the present invention, and FIG. 6B is a graph showing the distribution of the magnetic flux density in the axial direction.

FIG. 7 is a graph showing the distribution of axial magnetic flux density when different electromagnets for generating a gradient magnetic field are used.

FIG. 8A is a side view showing a gradient magnetic field generating electromagnet of a gyrotron device according to a fifth embodiment of the present invention, and FIG. 8B is a graph showing the distribution of magnetic flux density in the axial direction.

FIG. 9 is a sectional view showing a gyrotron device according to Embodiment 6 of the present invention.

FIG. 10 is a side view (a) showing a gradient magnetic field generating electromagnet of a gyrotron device according to a seventh embodiment of the present invention, and a graph (b) showing an axial magnetic flux density distribution.

FIG. 11 is a sectional view showing a gyrotron device according to an eighth embodiment of the present invention.

FIG. 12 is a cross-sectional view showing a gyrotron device using a conventional three-pole type electron gun.

FIG. 13 is a cross-sectional view showing a gyrotron device using a conventional bipolar electron gun.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 electron gun, 6 cavity resonator, 7 collector, 8 output window, 9 electron beam, 11 electromagnet for generating main magnetic field, 12
Electromagnets for generating an electron gun magnetic field, 20a, 20b, 21a,
21b, 24, 26a, 26b Electromagnet for generating gradient magnetic field, direction of Bz axial magnetic flux density (direction of axial magnetic field), 22a, 22b Electromagnet for generating gradient magnetic field (electromagnet wound in the same direction), 23a, 23b Coil ( Right-handed electromagnet and left-handed electromagnet), 24a, 24b, 24
c, 24d coil (electromagnet for generating gradient magnetic field), 25
a, 25e Coil end (input / output end), 25b, 25c,
25d intermediate tap, 35 reel (electrical insulator), 6
0 Gyrotron main body (gyrotron tube), 2
00 Gyrotron, 300 Gyrotron device.

Claims (6)

[Claims] An electron gun for emitting an electron beam, magnetic field generating means for generating an axial magnetic field for causing a swirling motion of the emitted electrons, and a cyclotron between a high frequency electromagnetic field resonating with the swirling electrons in an eigenmode. A gyro including a cavity for causing a resonance maser effect, a collector for collecting the electron beam having passed through the cavity, and an output window for taking out a high frequency generated by the cyclotron resonance maser effect In the tron device, the magnetic field generating means includes a main magnetic field generating electromagnet and a gradient magnetic field generating electromagnet that generate a magnetic field near the cavity resonator. During the oscillation operation at the frequency, a magnetic field of 10% or less of the axial magnetic flux density at the center of the cavity is generated, and A gyrotron device which generates an axial magnetic field having a desired distribution inside and near the cavity resonator by a magnetic field. 2. The electromagnet for generating a gradient magnetic field includes two or more electromagnets wound in the same direction, and is arranged such that the directions of the axial magnetic fields generated by the electromagnets wound in the same direction are opposite to each other. The gyrotron device according to claim 1, wherein: 3. The electromagnet for generating a gradient magnetic field includes at least one right-handed electromagnet and at least one left-handed electromagnet, and the directions of the axial magnetic fields generated by the right-handed electromagnet and the left-handed electromagnet are opposite to each other. The gyrotron device according to claim 1, wherein the gyrotron device is arranged so as to be arranged as follows. 4. An electron gun, a cavity resonator, a collector,
4. The gyrotron device according to claim 1, wherein the gyrotron provided with the output window performs a double harmonic oscillation operation. 5. The gyrotron device according to claim 1, wherein the electromagnet for generating a gradient magnetic field has one or more intermediate taps other than the input / output terminals. . 6. An electrical insulator capable of withstanding a voltage of at least 1 kV is provided between a gradient magnetic field generating electromagnet and a gyrotron tube to which the gradient magnetic field generating electromagnet is mounted. The gyrotron device according to any one of claims 1 to 4.