A method and system for evaluating the spatial scale of high-energy particle flux anomalies in near-Earth space before strong earthquakes

Abstract

The present invention is a method and system for evaluating the abnormal spatial scale of high-energy particle flux in near-Earth space before a strong earthquake, and belongs to the field of particle flux spatial scale evaluation technology. In view of the problem that the abnormal spatial scale of high-energy particle flux before an earthquake cannot be determined at present, the present invention includes the following steps: establishing an electromagnetic wave disturbance model caused by an earthquake in the form of electromagnetic disturbances of different frequencies; establishing a near-Earth space high-energy particle motion model based on the electromagnetic wave disturbance model and the motion vector of high-energy particles in near-Earth space; using the near-Earth space high-energy particle motion model, statistically analyzing the morphological changes of high-energy particles in electromagnetic disturbances of different frequencies caused by earthquakes, and obtaining the spatial scale of the change of high-energy particle flux before the earthquake and the results of its abnormal spatial distribution morphology, which are used as the standard for evaluating the abnormal spatial scale of high-energy particle flux before the earthquake. The method of the present invention covers different types of high-energy particle information anomalies under wide-band electromagnetic disturbances, and establishes a unified standard for the actual application process.

Description

Technical Field

[0001] The present invention relates to the technical field of particle flux spatial scale assessment, and in particular to a method and system for assessing the spatial scale of high-energy particle flux anomalies in near-earth space before a strong earthquake. Background Art

[0002] The broadband fluctuations generated by earthquakes propagate in near-Earth space and enter the ionosphere and magnetosphere. Due to the special motion form of high-energy particles in the magnetosphere, electromagnetic disturbances and high-energy particles will undergo wave-particle interaction, causing the motion form of high-energy particles to change.

[0003] The study of the correlation between earthquakes and high-energy particles began in the 1980s. In 1987, Voronov et al. first analyzed the experimental data of the Salut-7 satellite and concluded that there is a temporal correlation between high-energy charged particle bursts in near-Earth space and seismic activity. Subsequently, Aleshina et al. observed spatial high-energy charged particle bursts in seismic activity by analyzing the observation data of satellites such as Intercosmos-Bulgaris-1300, Meteor-3, Salyut-7 and Mir. The correlation between high-energy particles and seismic activity in time and space was confirmed through analysis. However, since the magnetic shell index L was used in their analysis, they focused more on spatial anomalies in the latitudinal direction. In order to further clarify the Earth's The effect of surface electromagnetic fluctuations on high-energy particles was studied, and the physical mechanism of the influence of seismic electromagnetic disturbances on high-energy particles was established. Li Xinqiao and others studied the influence of ground artificial sources on the precipitation of high-energy particles in near-Earth space. Through theoretical calculations, it was found that the high-frequency part of the wide-band electromagnetic radiation caused by earthquakes is almost completely absorbed during the propagation from the earthquake source to the surface. Among the low-frequency electromagnetic radiation that can reach the surface, only the ULF band electromagnetic waves with a frequency below 10-20Hz can penetrate the atmosphere and be observed by satellites. Yang Shaofeng and others observed ULF fluctuations during the 7.1-magnitude Hotan earthquake in Xinjiang on November 19, 1996. Zhao Shufan's research shows that the lower the frequency of electromagnetic fluctuations, the greater the Poynting energy flux density, which means that the low-frequency electromagnetic waves radiated by earthquakes are more likely to be transmitted to the satellite altitude and received.

[0004] Zhang Zhenxia et al. studied the possible connection between the diffusion coefficient of high-energy particles caused by the resonant interaction disturbance of VLF and high-energy particles and earthquakes, including the characteristics of the diffusion coefficient of high-energy electrons at different energies and pitch angles; Inan et al. used test particle simulation to determine the spatial distribution of electron precipitation caused by ground VLF transmitters, taking into account low-frequency fluctuations propagating along magnetic field lines, but not other fluctuations. At the same time, the frequency range of their calculations was concentrated in the VLF band, and no energy details were given; Abel and Thorne used the bounce-averaged pitch angle diffusion coefficient to calculate the electron lifetime driven by wave-particle interaction, but their study mainly considered the VLF band fluctuations, without considering the drift and bouncing effect of particles.

[0005] Due to the wide-spectrum characteristics of seismic electromagnetic radiation, in theory, the different motion forms of high-energy particles (electrons and protons) will produce wave-particle resonance interactions with seismic electromagnetic disturbances of different frequencies, causing changes in the motion forms of particles (energy, pitch angle changes, and even high-energy particle sedimentation).

[0006] Table 1 Typical motion patterns of high-energy particles in the magnetosphere and their corresponding time scales

[0007]

[0008] At present, the research methods for the abnormal high-energy particle flux before earthquakes are mainly focused on the analysis of the abnormal electron flux on the night side. The main disadvantages are as follows: first, the types of high-energy particles are limited to electrons, and the analysis of protons is relatively rare; second, the analysis of the abnormal high-energy particle flux before earthquakes (before, co-seismic and after earthquakes) is currently mainly limited to satellite observation analysis; third, due to the lack of clear theoretical basis and numerical simulation analysis, the current methods have a large degree of uncertainty, especially for the analysis of the same earthquake event, there are different results from different people, or different earthquakes are analyzed in different ways, without a unified analysis standard and basis. Since it is impossible to form a statistical analysis conclusion, the actual application effect is not good; fourth, the only theoretical analysis is limited to the diffusion coefficient of the FokkerPlanck equation using the adiabatic invariant, and its spatial position uses the magnetic shell index L as the independent variable. Since the magnetic shell index corresponds to the spatial position, it is a one-to-many attribute, which makes it impossible to correspond to the accurate longitude and latitude and altitude. At the same time, theoretical research is often limited to the diffusion caused by a specific range of frequencies, and the broadband electromagnetic disturbance of earthquakes is often not taken into account.

[0009] In view of the above shortcomings and deficiencies in practical applications, we proposed a method to evaluate the spatial scale of pre-earthquake high-energy particle flux anomalies, analyzed the reliability theoretically, and found the basis through joint comparative analysis of numerical simulation and actual satellite observations. Summary of the invention

[0010] The purpose of the present invention is to solve the problem that the existing use of satellite observation data to determine the flux anomaly of high-energy particles before an earthquake cannot effectively determine the spatial scale of the anomaly, and to propose a method and system for evaluating the spatial scale of the high-energy particle flux anomaly in near-Earth space before a strong earthquake, so as to solve the problems existing in the above-mentioned background technology.

[0011] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0012] The technical solution of the first aspect disclosed in the present invention is: a method for evaluating the spatial scale of high-energy particle flux anomaly in near-Earth space before a strong earthquake, comprising the following steps:

[0013] Step 1: Establish an electromagnetic wave disturbance model caused by an earthquake in the form of electromagnetic disturbances of different frequencies;

[0014] Step 2: Based on the electromagnetic wave disturbance model and the motion vectors of high-energy particles in near-Earth space, a motion model of high-energy particles in near-Earth space is established;

[0015] Step 3: Using the near-Earth space high-energy particle motion model, statistically analyze the changes in the morphology of high-energy particles caused by electromagnetic disturbances of different frequencies caused by earthquakes, and obtain the spatial scale of the changes in the high-energy particle flux before the earthquake and its spatial abnormal distribution morphology.

[0016] As a further preferred implementation of the above scheme, in step 1, the electromagnetic disturbance forms of different frequencies include low-frequency ULF fluctuations, ELF and VLF electromagnetic disturbances.

[0017] As a further preferred implementation of the above scheme, in step 2, the step of establishing a near-Earth space high-energy particle motion model includes:

[0018] Step 11: Calculate the pitch angle and position space term diffusion coefficient of the high-energy particle phase space through the electromagnetic wave perturbation model;

[0019] Step 12: Calculate the average time scale corresponding to the diffusion coefficient from the pitch angle;

[0020] Step 13: Calculate the drift velocity of high-energy particles in near-Earth space caused by magnetic field gradient and curvature;

[0021] Step 14: Calculate the product of the average time scale and the drift velocity to obtain the motion vectors of high-energy particles in different directions, and calculate the components of the motion vectors in the longitude and latitude directions to obtain the spatial scale information of high-energy particle precipitation;

[0022] Step 15: Establish a high-energy particle motion model in near-Earth space based on the spatial scale information of high-energy particle precipitation.

[0023] Based on the above technical solution, further, the diffusion coefficient of the high-energy particle position space term is calculated by the electromagnetic wave disturbance model, including:

[0024] Step 111: Convert the Vlasov equation to the position and momentum phase space (ξ(i=1,2,...6)=X,Y,Z,p,μ,φ) to obtain the magnetospheric high-energy particle distribution function F, which is expressed as:

[0025]

[0026] Where: p is the momentum of the particle, S represents the particle source;

[0027] The time rate of change of the phase space of a particle is expressed as:

[0028]

[0029] in: represents the time rate of change of the independent variable in the unperturbed phase space caused by the background field, Represents the time rate of change of the independent variable in phase space caused by the disturbance field:

[0030] Step 112: The above Vlasov equation is converted into the Fokker Planck equation by quasi-linear theory. The Fokker Planck equation is as follows:

[0031]

[0032]

[0033] in: is the diffusion coefficient.

[0034] As a further preferred implementation of the above scheme, in step 3, the results of obtaining the spatial scale of the change in the high-energy particle flux before the earthquake and its spatial abnormal distribution form are specifically:

[0035] The Monte Carlo method is used to simulate the motion patterns of a large number of high-energy particles, and the different patterns of high-energy particles in the presence and absence of a disturbance field are obtained. By comparing and analyzing the patterns of high-energy particles, the spatial scale of the change in high-energy particle flux and its spatial abnormal distribution pattern are obtained, thereby evaluating the abnormal spatial scale of the high-energy particle flux before an earthquake.

[0036] The technical solution of the second aspect disclosed in the present invention is: an evaluation system for evaluating the abnormal spatial scale of high-energy particle flux in near-earth space before a strong earthquake, comprising:

[0037] The model building module includes submodule 1 and submodule 2, which are used to build the electromagnetic wave disturbance model caused by earthquake and the high-energy particle motion model in near-Earth space respectively;

[0038] The statistical analysis module is used to perform statistical analysis on the morphological changes of high-energy particles under electromagnetic disturbances of different frequencies caused by earthquakes.

[0039] A further preferred embodiment of the above scheme is as follows: Submodule 2 includes a time scale unit, a drift velocity unit and a particle sedimentation space scale unit, wherein:

[0040] The time scale unit is the average spatial scale corresponding to the diffusion coefficient of the position space term calculated by the pitch angle of the high-energy particle phase space;

[0041] Drift velocity unit, used to calculate the drift velocity of high-energy particles in near-Earth space caused by magnetic field strength and curvature;

[0042] The particle precipitation spatial scale unit is used to calculate the components of the motion vector of high-energy particles in the longitude and latitude directions.

[0043] The technical solution of the third aspect disclosed in the present invention is: an electronic device, including a processor and a memory, the memory storing computer instructions, the processor being used to run the computer instructions stored in the memory to implement the steps of a method for evaluating the spatial scale of anomaly of high-energy particle flux in near-Earth space before a strong earthquake as described in any one of the above aspects.

[0044] The technical solution of the fourth aspect disclosed in the present invention is: a computer-readable storage medium storing computer instructions, and the computer instructions are used to enable a computer to execute the steps of a method for evaluating the spatial scale of anomaly of high-energy particle flux in near-Earth space before a strong earthquake as described in any one of the above aspects.

[0045] The present invention adopts the above scheme, and the beneficial effects produced are as follows:

[0046] 1. The present invention establishes an electromagnetic wave disturbance model caused by earthquakes in the form of electromagnetic field disturbances of different frequencies. By providing a high-frequency electromagnetic field model as a background electromagnetic field model for the motion of high-energy particles, coupling solutions for different types of particles and different operating forms can be achieved. Its advantage is that it covers different types of high-energy particle information anomalies caused by wide-band electromagnetic disturbances caused by earthquakes, rather than being limited to electronic anomalies on the night side.

[0047] 2. When calculating the diffusion coefficient of the spatial position term caused by electromagnetic field disturbances of different frequencies, the present invention uses the real three-dimensional spatial position diffusion coefficient instead of the diffusion coefficient of the magnetic shell index L, which can effectively determine the sedimentation range of high-energy particles in the longitude and latitude directions at the same time, and can more accurately obtain the evaluation results of the abnormal spatial distribution morphology of high-energy particles.

[0048] 3. The method of the present invention uses numerical simulation methods to improve the accuracy and certainty of satellite observations, obtains strong support from theory and actual satellite observations, and can establish unified standards in practical applications, providing new ideas for better evaluating the abnormal spatial scale of high-energy particle flux before strong earthquakes. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments.

[0050] Figure 1 The present invention is a technical flow chart of a method for evaluating the spatial scale of high-energy particle flux anomalies in near-Earth space before a strong earthquake. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Reference Figure 1 The present invention proposes a method for evaluating the spatial scale of high-energy particle flux anomalies in near-Earth space before a strong earthquake, comprising the following steps:

[0053] Step 1: Establish an electromagnetic wave disturbance model caused by earthquake by assuming electromagnetic disturbance forms of different frequencies, including low-frequency ULF fluctuations, ELF and VLF electromagnetic disturbances;

[0054] Step 2: Based on the electromagnetic wave disturbance model and the motion vectors of high-energy particles in near-Earth space, a motion model of high-energy particles in near-Earth space is established;

[0055] First, the throwing angle and the diffusion coefficient of the position space term of the high-energy particle phase space are calculated through the electromagnetic wave perturbation model, and then the average time scale corresponding to the diffusion coefficient is calculated from the throwing angle;

[0056] The process of calculating the diffusion coefficient of the high-energy particle position space term through the electromagnetic wave perturbation model is as follows:

[0057] Since the motion of high-energy particles needs to be described by the kinetic equation Fokker Planck equation, the Vlasov equation is converted to the position and momentum phase space (ξ(i=1,2,...6)=X,Y,Z,p,μ,φ), and the magnetospheric high-energy particle distribution function F is obtained. The equation satisfied by the distribution function F is:

[0058]

[0059] Where: p is the momentum of the particle, S represents the particle source;

[0060] The time rate of change of the phase space of a particle is expressed as:

[0061]

[0062] in: represents the time rate of change of the independent variable in the unperturbed phase space caused by the background field, Represents the time rate of change of the phase space independent variable caused by the disturbance field:

[0063] Step 112: The above Vlasov equation is converted into the Fokker Planck equation by quasi-linear theory. The Fokker Planck equation is as follows:

[0064]

[0065]

[0066] in: is the diffusion coefficient.

[0067] Second, calculate the drift velocity of high-energy particles in near-Earth space caused by magnetic field gradient and curvature;

[0068] Third, by multiplying the average time scale and the drift velocity, the motion vectors of high-energy particles in different directions are calculated, and the components of the above motion vectors in the longitude and latitude directions are calculated to obtain the spatial scale information of high-energy particle precipitation, thereby establishing a high-energy particle motion model in near-Earth space.

[0069] Step 3: Using the near-Earth space high-energy particle motion model, the high-energy particle morphology changes caused by electromagnetic disturbances of different frequencies caused by earthquakes are statistically analyzed to obtain the spatial scale of the high-energy particle flux changes before the earthquake and the results of its spatial abnormal distribution morphology, specifically:

[0070] The Monte Carlo method is used to simulate the motion forms of a large number of high-energy particles, and different forms of high-energy particles in the presence and absence of a disturbance field are obtained. By performing statistical comparative analysis on the forms of high-energy particles and using satellite observations to obtain the abnormal spatial scale of high-energy particles, the particle forms obtained by the model of the present invention are compared with satellite observation data, and the model of the present invention is continuously iterated and optimized to obtain the accurate spatial scale of the change in high-energy particle flux and its spatial abnormal distribution form, thereby evaluating the abnormal spatial scale of the high-energy particle flux before an earthquake.

[0071] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating the spatial scale of high-energy particle flux anomalies in near-Earth space before a strong earthquake, characterized in that: The following steps are involved: Step 1: Establishing an electromagnetic wave disturbance model caused by an earthquake in the form of electromagnetic disturbances of different frequencies; the electromagnetic disturbances of different frequencies include low-frequency ULF fluctuations, ELF and VLF electromagnetic disturbances; Step 2: Based on the electromagnetic wave disturbance model and the motion vectors of high-energy particles in near-Earth space, a motion model of high-energy particles in near-Earth space is established; The steps to establish a high-energy particle motion model in near-Earth space include: Step 11: Calculate the pitch angle and position space term diffusion coefficient of the high-energy particle phase space through the electromagnetic wave perturbation model; The calculation of the diffusion coefficient of the high-energy particle position space term through the electromagnetic wave disturbance model includes: Step 111: Convert the Vlasov equation to the position and momentum phase space to obtain the magnetospheric high-energy particle distribution function, which is expressed as: in: represents the particle source, F and t are the particle phase space density distribution function and time, ξ i represents the position and momentum phase space, i=1,2,3,4,5,6, and the six basic phase space parameters are X, Y, Z, p, μ, φ, where X, Y, Z represent the three-dimensional coordinate position of the particle, p, μ, φ represent the particle momentum, the cosine of the particle pitch angle, and the azimuth, respectively; The time rate of change of the phase space of a particle is expressed as: in: represents the time rate of change of the independent variable in the unperturbed phase space caused by the background field, represents the time rate of change of the independent variable in phase space caused by the disturbance field; Step 112: The above Vlasov equation is converted into the Fokker Planck equation by quasi-linear theory. The Fokker Planck equation is as follows: in: is the diffusion coefficient, T c represents the perturbation time, τ represents 0-T c The time of a certain disturbance; represents the average time rate of change of the independent variable in phase space caused by the disturbance field; Step 12: Calculate the average time scale corresponding to the diffusion coefficient from the pitch angle; Step 13: Calculate the drift velocity of high-energy particles in near-Earth space caused by magnetic field gradient and curvature; Step 14: Calculate the product of the average time scale and the drift velocity to obtain the motion vectors of high-energy particles in different directions, and calculate the components of the motion vectors in the longitude and latitude directions to obtain the spatial scale information of high-energy particle precipitation; Step 15: Establish a near-Earth space high-energy particle motion model based on the high-energy particle precipitation spatial scale information; Step 3: Using the near-Earth space high-energy particle motion model, statistically analyze the changes in the morphology of high-energy particles caused by electromagnetic disturbances of different frequencies caused by earthquakes, and obtain the spatial scale of the changes in the high-energy particle flux before the earthquake and its spatial abnormal distribution morphology.

2. The method for evaluating the spatial scale of high-energy particle flux anomaly in near-Earth space before a strong earthquake according to claim 1 is characterized in that: In step 3, the spatial scale of the change in high-energy particle flux before the earthquake and its spatial abnormal distribution form are obtained as follows: The Monte Carlo method is used to simulate the motion forms of a large number of high-energy particles, and the different forms of high-energy particles in the presence and absence of a disturbance field are obtained. By comparing and analyzing the forms of high-energy particles, the spatial scale of the change in high-energy particle flux and its spatial abnormal distribution form are obtained, thereby evaluating the abnormal spatial scale of the high-energy particle flux before an earthquake.

3. An evaluation system, characterized in that: A method for evaluating the spatial scale of high-energy particle flux anomalies in near-Earth space before a strong earthquake as described in any one of claims 1 to 2, comprising: The model building module includes submodule 1 and submodule 2, which are used to build the electromagnetic wave disturbance model caused by earthquake and the high-energy particle motion model in near-Earth space respectively; The statistical analysis module is used to perform statistical analysis on the morphological changes of high-energy particles under electromagnetic disturbances of different frequencies caused by earthquakes.

4. An evaluation system according to claim 3, characterized in that: Submodule 2 includes time scale unit, drift velocity unit and particle sedimentation space scale unit, among which: The time scale unit is the average spatial scale corresponding to the diffusion coefficient of the position space term calculated by the pitch angle of the high-energy particle phase space; Drift velocity unit, used to calculate the drift velocity of high-energy particles in near-Earth space caused by magnetic field strength and curvature; The particle precipitation spatial scale unit is used to calculate the components of the motion vector of high-energy particles in the longitude and latitude directions.

5. An electronic device, comprising a processor and a memory, characterized in that: The memory stores computer instructions, and the processor is used to execute the computer instructions stored in the memory to implement the steps of a method for evaluating the spatial scale of high-energy particle flux anomalies in near-Earth space before a strong earthquake as described in any one of claims 1-2.

6. A computer-readable storage medium storing computer instructions, characterized in that: The computer instructions are used to enable a computer to execute the steps of a method for evaluating the spatial scale of high-energy particle flux anomalies in near-Earth space before a strong earthquake as described in any one of claims 1-2.

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