CN114624256B - Three-dimensional microwave reflection system and method for measuring instability modulus of magnetic fluid - Google Patents
Three-dimensional microwave reflection system and method for measuring instability modulus of magnetic fluid Download PDFInfo
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Abstract
The invention discloses a three-dimensional microwave reflection system and a method for measuring the instability modulus of magnetic fluid, wherein the system comprises a point frequency source, a comb spectrum generator, a filter, a power divider, a modulation link, a reflection assembly and a focusing assembly; the point frequency source provides local oscillation input for the comb spectrum generator; the comb spectrum generator generates multi-frequency-point microwaves; the filter filters the multi-frequency microwave; the power divider divides one path of microwave signals output by the filter into N paths of microwave signals; at least 2 paths of microwave signals are respectively processed by a modulation link and then are adjusted by a reflection assembly to realize that the different polar positions are perpendicular to the magnetic force lines and are injected into the plasma core region, and at least 2 paths of microwave signals are respectively processed by a modulation link and then are adjusted by a focusing assembly to realize that the different annular positions are perpendicular to the magnetic force lines and are injected into the plasma core region. The invention can realize the space-time measurement of instability from three dimensions of radial, annular and polar directions, and overcomes the limitation existing in the prior diagnosis technology.
Description
Technical Field
The invention belongs to the technical field of magnetic confinement plasmas, and particularly relates to a three-dimensional microwave reflection system and method for measuring the instability modulus of magnetic fluid. The invention is especially suitable for measuring the time-space characteristics of the magnetic fluid instability in different plasma discharge environments, and is a diagnosis technology suitable for various plasma conditions.
Background
Magnetic fluid instabilities of different dimensions exist in magnetically confined fusion plasmas. Numerous evidence suggests that these instabilities reduce the efficiency of external auxiliary heating, limit plasma confinement performance, and even cause serious damage to the first wall of the fusion device. Therefore, in order to understand these instability-generating mechanisms and find effective control methods, systematic and in-depth measurements of their experimental spatiotemporal characteristics must be made. Magnetic fluid instability typically causes magnetic, temperature and density disturbances. The main means of measuring magnetic disturbances is a magnetic probe, but such diagnostics are often arranged at the plasma edge, insensitive to instabilities in the core region, and not able to detect the core region. The main means for measuring temperature disturbance is an electron cyclotron radiometer and an imaging system thereof, but the diagnosis can be cut off when the electron density is higher, and the system can not work normally. Diagnostics of measured density disturbances are mainly interferometers, beam-generating spectrometers and microwave reflectometers. The interferometer is a chord integral measurement means and does not have the capability of localized measurement; beam-generating spectrometers rely heavily on neutral beams and are not operable without neutral beams. The reflectometer is mainly based on the cut-off phenomenon of microwave when propagating in plasma, and is a diagnosis which is independent of other conditions, has no disturbance to the plasma and is sensitive to density disturbance. Different frequencies generally correspond to different cut-off densities, so that reflectometers are considered a diagnosis with localized measurement capability. Such diagnostics have application in many fusion devices throughout the world, but are essentially based on one-or two-dimensional (radial and polar) measurements, and cannot measure the most important parameters of magnetic fluid instability, namely the circumferential and polar moduli, simultaneously. This makes the core magnetic fluid instability modulus measurement very difficult, limiting the progress of physical research.
Disclosure of Invention
Therefore, the invention provides a three-dimensional microwave reflection system for measuring the instability modulus of magnetic fluid, which aims at the challenges of the prior diagnosis technology for measuring the instability of a core region, in particular to the problems that the circumferential modulus and the polar modulus of the high-frequency instability of the core cannot be measured. The three-dimensional microwave reflection system can realize space-time measurement of instability in three dimensions of radial, annular and polar directions, and provides technical support and data support for determining the modulus of instability of magnetic fluid.
The invention is realized by the following technical scheme:
the three-dimensional microwave reflection system for measuring the instability modulus of the magnetic fluid comprises a point frequency source, a comb spectrum generator, a filter, a power divider, a modulation link, a reflection assembly and a focusing assembly;
the point frequency source provides local oscillation input for the comb spectrum generator;
the comb spectrum generator generates multi-frequency-point microwaves after receiving local oscillator input;
the filter filters multi-frequency-point microwaves generated by the comb spectrum generator;
the power divider divides one path of microwave signals output by the filter into N paths of microwave signals, wherein N is a positive integer greater than or equal to 4;
at least 2 paths of microwave signals are respectively processed by a modulation link and then are adjusted by a reflection assembly to realize that the different polar positions are perpendicular to the magnetic force lines and are injected into the plasma core region, and at least 2 paths of microwave signals are respectively processed by a modulation link and then are adjusted by a focusing assembly to realize that the different annular positions are perpendicular to the magnetic force lines and are injected into the plasma core region.
As a preferred embodiment, the modulation link of the present invention comprises an amplifier, a first directional coupler, a demodulation module, a second directional coupler, and a standard antenna;
the input end of the amplifier is connected with an output end of the power divider, the output end of the amplifier is connected with the input end of the first directional coupler, the through end of the first directional coupler is connected with the input end of the second directional coupler, the through end of the second directional coupler is connected with the standard antenna, and the coupling ends of the first directional coupler and the second directional coupler are both connected with the demodulation module.
As a preferred embodiment, the demodulation module of the present invention is composed of a first multiplexer 7i, a quadrature demodulation array 7ii, and a second multiplexer 7 iii;
the input end of the first multiplexer 7i is connected with the coupling end of the first directional coupler, and a plurality of output ends of the first multiplexer 7i are connected with the local oscillation end of the quadrature demodulation array 7 ii;
an input end of the second multiplexer 7iii is connected with a coupling end of a second directional coupler, and a plurality of output ends of the second multiplexer 7iii are connected with a radio frequency end of the quadrature demodulation array 7 ii;
the standard antenna is used for transmitting detection microwaves and receiving transmitting signals at the same time.
As a preferred embodiment, the second directional coupler of the present invention is used to transmit microwaves and reflected signals received by a standard antenna at the same time.
As a preferred embodiment, the reflecting assembly of the present invention includes a first reflecting mirror and a second reflecting mirror;
the first reflecting mirror is used for deviating microwaves from the intermediate frequency surface so as to realize incidence of different polar positions;
the second reflecting mirror is used for adjusting the incidence angle of microwaves and ensuring that the microwaves are perpendicular to the magnetic force lines and enter the plasma core region.
As a preferred embodiment, the focusing assembly of the present invention comprises a focusing lens;
the focusing lens is used for converging microwaves so as to enhance the measurement signal.
As a preferred embodiment, the comb spectrum generator of the present invention employs frequency doubling diodes.
As a preferred embodiment, the power divider of the present invention employs a four-way power divider.
As a preferred embodiment, the operating frequency of the amplifier of the invention is matched to the filtering frequency of the filter.
On the other hand, the invention provides a measuring method based on the three-dimensional microwave reflection system, which comprises the following steps:
signals of two measuring channels with the same frequency but different spatial positions are selected to carry out Fourier transformation and are respectively extracted from power spectrums;
calculating a wave number-frequency spectral density function based on the self-power spectrum;
integrating the wave number-frequency spectrum density function in a wave number space, and calculating an average wave number;
and obtaining modulus information according to the relationship between the magnetic fluid instability circumferential modulus or polar modulus and the average wave number.
As a preferred embodiment, the present invention calculates the wavenumber-frequency spectral density function by:
wherein M is the number of ensembles of fluctuation data to be analyzed,self-power spectrum of two fluctuation signals of the space interval x respectively +.>Is the mutual bit spectrum of the two measurement channel signals.
The invention has the following advantages and beneficial effects:
the invention realizes the space-time measurement of the instability from three dimensions of radial direction, annular direction and polar direction based on the three-dimensional microwave reflection system, combines a two-point correlation analysis method based on Fourier transformation, realizes the analog-digital measurement of the instability of the magnetic fluid, and overcomes the limitations of the prior diagnosis technology.
Drawings
The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention. In the drawings:
fig. 1 is a schematic structural diagram of a three-dimensional microwave reflection system according to the present invention.
In the drawings, the reference numerals and corresponding part names:
the device comprises a 1-point frequency source, a 2-comb spectrum generator, a 3-filter, a 4-four-way power divider, a 5-amplifier, a 6-first directional coupler, a 7-demodulation module, an 8-second directional coupler, a 9-standard antenna, a 10 a-first reflector, a 10 b-first focusing lens, a 10 c-second focusing lens, a 10 d-third reflector, an 11 a-second reflector and an 11 d-fourth reflector.
Detailed Description
Hereinafter, the terms "comprises" or "comprising" as may be used in various embodiments of the present invention indicate the presence of inventive functions, operations or elements, and are not limiting of the addition of one or more functions, operations or elements. Furthermore, as used in various embodiments of the invention, the terms "comprises," "comprising," and their cognate terms are intended to refer to a particular feature, number, step, operation, element, component, or combination of the foregoing, and should not be interpreted as first excluding the existence of or increasing likelihood of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing.
In various embodiments of the invention, the expression "or" at least one of a or/and B "includes any or all combinations of the words listed simultaneously. For example, the expression "a or B" or "at least one of a or/and B" may include a, may include B or may include both a and B.
Expressions (such as "first", "second", etc.) used in the various embodiments of the invention may modify various constituent elements in the various embodiments, but the respective constituent elements may not be limited. For example, the above description does not limit the order and/or importance of the elements. The above description is only intended to distinguish one element from another element. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of various embodiments of the present invention.
It should be noted that: if it is described to "connect" one component element to another component element, a first component element may be directly connected to a second component element, and a third component element may be "connected" between the first and second component elements. Conversely, when one constituent element is "directly connected" to another constituent element, it is understood that there is no third constituent element between the first constituent element and the second constituent element.
The terminology used in the various embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the various embodiments of the invention. As used herein, the singular is intended to include the plural as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the invention belong. The terms (such as those defined in commonly used dictionaries) will be interpreted as having a meaning that is the same as the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein in connection with the various embodiments of the invention.
For the purpose of making apparent the objects, technical solutions and advantages of the present invention, the present invention will be further described in detail with reference to the following examples and the accompanying drawings, wherein the exemplary embodiments of the present invention and the descriptions thereof are for illustrating the present invention only and are not to be construed as limiting the present invention.
Examples
The existing technology for measuring the instability of the magnetic fluid has limitations, particularly the measurement of the instability modulus of the magnetic fluid of the plasma core is difficult, and based on the fact, the embodiment provides a three-dimensional microwave reflection system for measuring the instability modulus of the magnetic fluid, which can realize the time-space measurement of the instability in three dimensions of radial, annular and polar directions and can determine the instability modulus of the magnetic fluid by combining a related analysis method.
As shown in fig. 1, the system of the present embodiment mainly includes a point frequency source 1, a comb spectrum generator 2, a filter 3, a power divider 4, an amplifier 5, directional couplers (a first directional coupler 6 and a second directional coupler 8), a demodulation module 7, a standard antenna 9, reflection components (a first mirror 10a, a second mirror 11a, a third mirror 10d and a fourth mirror 11 d), and focusing components (a first focusing lens 10b and a second focusing lens 10 c), and the like.
The point frequency source 1 provides local oscillation input for the comb spectrum generator 2, and requires enough power to drive the comb spectrum generator 2; the comb spectrum generator 2 is essentially a frequency doubling diode, and can generate multiple frequency doubling harmonic waves after receiving specific local oscillator input; the filter 3 is used for filtering the multi-frequency-point microwaves generated by the comb spectrum generator 2 so as to select needed frequency components, and meanwhile, interference of other frequencies on a system can be eliminated or reduced; power dividerDividing one microwave signal into multiple paths of signals, so as to realize measurement in three directions of annular direction, radial direction and polar direction in one set of system; the operating frequency of the amplifier 5 is matched to the filtering frequency of the filter 3(i.e., the operating frequency ranges of the two devices are identical)And to drive the mixer in the demodulation module 7, a relatively high gain is required; the first directional coupler 6 divides one microwave into two microwaves, one microwave serves as emission, and the other microwave serves as local oscillation input of a mixer in the demodulation module 7; the demodulation module 7 is used for distinguishing different frequency components in the microwaves and respectively carrying out orthogonal demodulation on the different frequency components; the second directional coupler 8 is used for transmitting microwaves and receiving signals, and in this embodiment, has a high isolation; the standard antenna 9 is used for transmitting detection microwaves and receiving reflected signals at the same time, and the reflecting component is used for realizing incidence of microwaves from different polar positions and ensuring that the microwaves are perpendicularly incident into the plasma core region; the focusing lenses in the focusing assembly are arranged at different circumferential positions and are mainly used for converging microwaves so as to enhance the measurement signal.
In this embodiment, the four-power divider is taken as an example to describe the three-position microwave reflection system in detail:
as shown in fig. 1, the four output ports of the four-way splitter are a, b, c, d in turn, and for convenience of description, the devices or modules to which each output port is subsequently connected are also labeled a, b, c, d.
As shown in fig. 1, the connection relationship between each device or module in the system of this embodiment is specifically:
the output end of the point frequency source 1 is connected with the input end of the comb spectrum generator 2, the output end of the comb spectrum generator 2 is connected with the input end of the filter 3, and the output end of the filter 3 is connected with the input end of the four-power divider;
the output end d of the four-power divider is connected with the input end of the amplifier 5d, the output end of the amplifier 5d is connected with the input end of the first directional coupler 6d, the through end of the first directional coupler 6d is connected with the input end of the second directional coupler 8d, the through end of the second directional coupler 8d is connected with the standard antenna 9d, microwaves emitted by the standard antenna 9d are reflected by the reflecting component (the third reflecting mirror 10d and the fourth reflecting mirror 11 d) and then are emitted into plasma from the lower part of the middle plane window perpendicular to magnetic lines of force, and the coupling ends of the first directional coupler 6d and the second directional coupler 8d are respectively connected with the demodulation module 7d. The demodulation module 7d of the present embodiment mainly comprises a first four-way multiplexer 7i, a second four-way multiplexer 7iii and an orthogonal demodulation array 7ii, where the first four-way multiplexer 7i and the second four-way multiplexer 7iii have functions of power division and filtering at the same time, so that different frequency components in microwaves can be distinguished, and the orthogonal demodulation array 7ii is used to respectively perform orthogonal demodulation on the different frequency components; the coupling ends of the first directional coupler 6d and the second directional coupler 8d are respectively connected with the input ends of the first four-way multiplexer 7i and the second four-way multiplexer 7 iii; the four output terminals of the first four-way multiplexer 7i and the second four-way multiplexer 7iii are respectively connected with the local oscillation terminal and the radio frequency terminal of the quadrature demodulation array 7 ii.
The output end a of the four-power divider is connected with the input end of the amplifier 5a, the output end of the amplifier 5a is connected with the input end of the first directional coupler 6a, the through end of the first directional coupler 6a is connected with the input end of the second directional coupler 8a, the through end of the second directional coupler 8a is connected with the standard antenna 9a, microwaves emitted by the standard antenna 9a are emitted by the reflecting component (the first reflecting mirror 10a and the second reflecting mirror 11 a) and then are emitted into plasma from the upper part of the middle plane window perpendicular to magnetic lines of force, and the coupling ends of the first directional coupler 6a and the second directional coupler 8a are sequentially connected with the demodulation module 7a. The demodulation module 7a and the demodulation module 7d of the present embodiment have the same structure and function (not shown in the figure), and mainly comprise a first four-way multiplexer 7i, a second four-way multiplexer 7iii and a quadrature demodulation array 7ii, wherein the coupling ends of the first directional coupler 6a and the second directional coupler 8a are respectively connected with the input ends of the first four-way multiplexer 7i and the second four-way multiplexer 7 iii; the four output terminals of the first four-way multiplexer 7i and the second four-way multiplexer 7iii are respectively connected with the local oscillation terminal and the radio frequency terminal of the quadrature demodulation array 7 ii.
The output end b of the four-power divider is connected with the input end of the amplifier 5b, the output end of the amplifier 5b is connected with the input end of the first directional coupler 6b, the through end of the first directional coupler 6b is connected with the input end of the second directional coupler 8b, the through end of the second directional coupler 8b is connected with the standard antenna 9b, microwaves emitted by the standard antenna 9b are focused by the focusing assembly (the first focusing lens 10 b) and then are emitted into plasma from the middle plane window perpendicular to magnetic lines of force, and the coupling ends of the first directional coupler 6b and the second directional coupler 8b are respectively connected with the demodulation module 7b. The demodulation module 7b of the present embodiment has the same structure and function and structure as those of the demodulation module 7d (not shown in the figure), and mainly comprises a first four-way multiplexer 7i, a second four-way multiplexer 7iii and a quadrature demodulation array 7ii, wherein the coupling ends of the first directional coupler 6b and the second directional coupler 8b are respectively connected with the input ends of the first four-way multiplexer 7i and the second four-way multiplexer 7 iii; the four output terminals of the first four-way multiplexer 7i and the second four-way multiplexer 7iii are respectively connected with the local oscillation terminal and the radio frequency terminal of the quadrature demodulation array 7 ii.
The output end c of the four-power divider is connected with the input end of the amplifier 5c, the output end of the amplifier 5c is connected with the input end of the first directional coupler 6c, the through end of the first directional coupler 6c is connected with the input end of the second directional coupler 8c, the through end of the second directional coupler 8c is connected with the standard antenna 9c, microwaves emitted by the standard antenna 9c are focused by the focusing assembly (the second focusing lens 10 c) and then are emitted into plasma from the middle plane window perpendicular to magnetic lines of force, and the coupling ends of the first directional coupler 6c and the second directional coupler 8c are respectively connected with the demodulation module 7c. The demodulation module 7c of the present embodiment has the same structure and function as the demodulation module 7d (not shown in the figure), and mainly comprises a first four-way multiplexer 7i, a second four-way multiplexer 7iii and a quadrature demodulation array 7ii, wherein the coupling ends of the first directional coupler 6c and the second directional coupler 8c are respectively connected with the input ends of the first four-way multiplexer 7i and the second four-way multiplexer 7 iii; the four output terminals of the first four-way multiplexer 7i and the second four-way multiplexer 7iii are respectively connected with the local oscillation terminal and the radio frequency terminal of the quadrature demodulation array 7 ii.
The standard antennas 9a,9b,9c and 9d of the present embodiment serve as both transmitting and receiving antennas. The three incident windows of the link a, the link d and the link b are positioned at the same annular position; link b and link c are in different circumferential positions. Therefore, the antenna is arranged in four different directions, and a plurality of working frequencies can be generated by the dressing spectrum, so that the single system can realize the measurement of the annular direction, the radial direction and the polar direction, and the measurement of the annular direction and the polar direction modulus of the instability of the magnetic fluid is possible.
The first mirror 10a and the third mirror 10d in the present embodiment deviate microwaves from the intermediate frequency plane, thereby realizing incidence at different polar positions; the second reflecting mirror 11a and the fourth reflecting mirror 11d can flexibly adjust angles so as to effectively ensure that microwaves are injected into the plasma core region perpendicular to magnetic lines; the first focusing lens 10b and the second focusing lens 10c are installed at different circumferential positions, and are mainly used to converge microwaves so as to enhance the measurement signal.
The three-position microwave reflection system provided by the embodiment has 4 (radial) x 2 (polar) x 2 (annular) =16 measurement points, so that in practical application, not only the radial space position of the magnetic fluid instability can be directly obtained, but also the polar modulus and the annular modulus of the instability mode can be obtained by a two-point correlation analysis method.
The specific process of performing the magnetic fluid instability modulus measurement based on the three-dimensional emission system in the embodiment comprises the following steps:
1. selecting signals of two measuring channels with the same frequency but different space positions (the space interval is marked as x and can be determined through wave trace tracking), selecting a link b and a link c measuring system when measuring the circumferential modulus, wherein the two measuring points are at different circumferential positions, selecting a link a and a link d when measuring the polar modulus, and performing Fourier transformation on the signals of the two measuring channels with the two measuring points at different polar positions and extracting the signals from power spectrums respectively;
2. calculating wave number-frequency spectral density function Wherein M is the number of ensembles of fluctuation data to be analyzed, P1if, P2if are the self-power spectra of two fluctuation signals of the space interval x, respectively, +.>Is the mutual bit spectrum of the two signals;
3. integrating s (k, f) in wavenumber space, i.e., s (k) = Σ f s (k, f), and the average wavenumber k (f) = Σis found k k·s(k，f)/s(f)；
4. N=k according to the relationship between the magnetic fluid instability circumferential and polar moduli and the average wave number n (f)·x n And m=k m (f)·x m Modulus information is obtained, wherein k (f) and x are respectively marked by different subscripts for the purpose of representing the distinction between circumferential modulus and polar modulus.
Since the microwave measurement is not limited by the plasma discharge conditions, no additional disturbance to the plasma is generated. Therefore, the three-dimensional microwave reflection system and the method provided by the embodiment are universal and full-energy plasma diagnosis technologies, and the defect that the existing diagnosis cannot measure the instability modulus of the core is thoroughly overcome.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. The three-dimensional microwave reflection system for measuring the instability modulus of the magnetic fluid is characterized by comprising a point frequency source, a comb spectrum generator, a filter, a power divider, a modulation link, a reflection assembly and a focusing assembly;
the point frequency source provides local oscillation input for the comb spectrum generator;
the comb spectrum generator generates multi-frequency-point microwaves after receiving local oscillator input;
the filter filters multi-frequency-point microwaves generated by the comb spectrum generator;
the power divider divides one path of microwave signals output by the filter into N paths of microwave signals, wherein N is a positive integer greater than or equal to 4;
at least 2 paths of microwave signals are respectively processed by a modulation link and then are adjusted by a reflection assembly to realize that the different polar positions are perpendicular to the magnetic force lines and are injected into the plasma core region, and at least 2 paths of microwave signals are respectively processed by a modulation link and then are adjusted by a focusing assembly to realize that the different annular positions are perpendicular to the magnetic force lines and are injected into the plasma core region.
2. The three-dimensional microwave reflection system for measuring a magnetic fluid instability modulus according to claim 1, wherein the modulation link comprises an amplifier, a first directional coupler, a demodulation module, a second directional coupler and a standard antenna;
the input end of the amplifier is connected with an output end of the power divider, the output end of the amplifier is connected with the input end of the first directional coupler, the through end of the first directional coupler is connected with the input end of the second directional coupler, the through end of the second directional coupler is connected with the standard antenna, and the coupling ends of the first directional coupler and the second directional coupler are both connected with the demodulation module.
3. The three-dimensional microwave reflection system for measuring the instability modulus of a magnetic fluid according to claim 2, wherein the demodulation module is composed of a first multiplexer 7i, a quadrature demodulation array 7ii and a second multiplexer 7 iii;
the input end of the first multiplexer 7i is connected with the coupling end of the first directional coupler, and a plurality of output ends of the first multiplexer 7i are connected with the local oscillation end of the quadrature demodulation array 7 ii;
an input end of the second multiplexer 7iii is connected with a coupling end of a second directional coupler, and a plurality of output ends of the second multiplexer 7iii are connected with a radio frequency end of the quadrature demodulation array 7 ii;
the standard antenna is used for transmitting detection microwaves and receiving transmitting signals at the same time.
4. A three-dimensional microwave reflection system for measuring the instability modulus of a magnetic fluid according to any of claims 2 to 3, wherein the second directional coupler is used for both transmitting microwaves and reflected signals received by a standard antenna.
5. A three-dimensional microwave reflection system for measuring a magnetic fluid instability modulus according to any of claims 1 to 3, wherein the reflection assembly comprises a first mirror and a second mirror;
the first reflecting mirror is used for deviating microwaves from the intermediate frequency surface so as to realize incidence of different polar positions;
the second reflecting mirror is used for adjusting the incidence angle of microwaves and ensuring that the microwaves are perpendicular to the magnetic force lines and enter the plasma core region.
6. A three-dimensional microwave reflection system for measuring the instability modulus of a magnetic fluid according to any of claims 1 to 3, wherein the focusing assembly comprises a focusing lens;
the focusing lens is used for converging microwaves so as to enhance the measurement signal.
7. A three-dimensional microwave reflection system for measuring the instability modulus of a magnetic fluid according to any of claims 1 to 3, wherein the comb spectrum generator employs a frequency doubling diode;
and/or the power divider adopts a four-power divider.
8. A three-dimensional microwave reflection system for measuring a magnetic fluid instability modulus according to any of claims 2 to 3, wherein the operating frequency of the amplifier is matched to the filtering frequency of the filter.
9. A measurement method based on the three-dimensional microwave reflection system for measuring the instability modulus of a magnetic fluid according to any of claims 1 to 8, comprising:
signals of two measuring channels with the same frequency but different spatial positions are selected to carry out Fourier transformation and are respectively extracted from power spectrums;
calculating a wave number-frequency spectral density function based on the self-power spectrum;
integrating the wave number-frequency spectrum density function in a wave number space, and calculating an average wave number;
and obtaining modulus information according to the relationship between the magnetic fluid instability circumferential modulus or polar modulus and the average wave number.
10. A measurement method according to claim 9, characterized in that the wave number-frequency spectral density function is calculated by:
wherein M is the number of ensembles of fluctuation data to be analyzed,self-power spectrum of two fluctuation signals of the space interval x respectively +.> Is the mutual bit spectrum of the two measurement channel signals.
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