A method and system for calculating spatial distribution of late-time nuclear electromagnetic pulse electromagnetic fields

Abstract

The application discloses a kind of late nuclear electromagnetic pulse electromagnetic field space distribution calculation method and system, solve the technical problem that electromagnetic field calculated by existing late nuclear electromagnetic pulse calculation method cannot reflect spatial variation, specifically according to the formation mechanism of late nuclear electromagnetic pulse, the calculation process is decomposed into four modules, i.e. atmosphere ionization calculation, fragment cloud movement calculation, atmosphere plasma movement calculation and low-frequency electromagnetic field propagation calculation.The method can calculate the spatial distribution of late nuclear electromagnetic pulse electromagnetic field, can reflect the influence of explosion parameters and environmental parameters on electromagnetic field, so that its actual use is more certain.

Description

Technical Field

[0001] This invention relates to the electromagnetic field of late-stage nuclear electromagnetic pulses, and more specifically to a method and system for calculating the spatial distribution of the electromagnetic field of late-stage nuclear electromagnetic pulses. Background Technology

[0002] Nuclear explosions generate temperatures of tens of millions of degrees Celsius, causing the projectile materials and explosion products to exist in a plasma state, known as a debris cloud. The thin upper atmosphere results in a very low collision frequency of debris ions and a long path of freedom, leading to slow plasma recombination and the debris cloud remaining charged for a long time. The movement of the charged debris cloud and other heated atmospheric plasma generated by the nuclear explosion disturbs the Earth's magnetic field, generating disturbed electromagnetic waves. These electromagnetic waves, when they penetrate the ionization shield and reach the ground, constitute the late-stage nuclear electromagnetic pulse (LEP). Currently, the commonly used method for calculating the LEP is to calculate the electromagnetic field using the IEC 61000-2-9 standard electric field proposed by the International Electrotechnical Commission (IEC), combined with specific Earth conductivity data, and employing integral transformation. Although this method is convenient and efficient, the lack of spatial distribution in the IEC standard electric field means that the resulting electromagnetic field cannot reflect spatial variations or the influence of explosion and environmental parameters, introducing uncertainties into practical applications. Summary of the Invention

[0003] To address the technical problem that existing methods for calculating late-stage nuclear electromagnetic pulses (NEPs) cannot reflect spatial variations in the electromagnetic field, this invention provides a method and system for calculating the spatial distribution of the electromagnetic field in NEPs.

[0004] The basic concept of this invention is to decompose the calculation process into four modules based on the formation mechanism of late-stage nuclear electromagnetic pulses: atmospheric ionization calculation, debris cloud motion calculation, atmospheric plasma motion calculation, and low-frequency electromagnetic field propagation calculation.

[0005] The technical solution of the present invention is as follows:

[0006] A method for calculating the spatial distribution of the electromagnetic field in a late-stage nuclear electromagnetic pulse, characterized by the following steps:

[0007] Step 1: Obtain information on the upper-air environment, the energy spectrum of high-energy rays generated by the nuclear explosion, and the density distribution of the initial debris cloud; perform atmospheric ionization effect calculations to obtain the density of each component of the atmospheric plasma after the nuclear explosion.

[0008] Step 2: Obtain the initial debris cloud state. Based on the high-altitude environmental information and the density of each component of atmospheric plasma obtained in Step 1, perform debris cloud motion calculations to obtain the density distribution of the debris cloud and atmospheric deposition energy.

[0009] Step 3: Replace the initial fragment cloud density distribution in Step 1 with the fragment cloud density distribution obtained in Step 2, repeat Step 1, then update the initial fragment cloud state, repeat Step 2, and obtain the updated atmospheric plasma component densities and atmospheric deposition energy.

[0010] Step 4: Using the updated atmospheric deposition energy as the initial driving source, atmospheric motion calculations are performed based on the upper-air environment information and the updated atmospheric plasma component densities to obtain atmospheric plasma velocity distribution information.

[0011] Step 5: Based on the updated atmospheric plasma component densities, the atmospheric plasma velocity distribution information obtained in Step 4, and the upper-altitude environment information, perform electromagnetic field calculations to obtain electromagnetic field distribution information.

[0012] Step 6: Based on the continuous iteration of steps 1-3, repeat steps 4-5 until the preset calculation time is reached to obtain the final electromagnetic field distribution information, which is the spatial distribution of the electromagnetic field of the late electromagnetic pulse.

[0013] Further, step 1 specifically involves: acquiring information about the upper-air environment, the energy spectrum of high-energy rays generated by the nuclear explosion, and the density distribution of the initial debris cloud; calculating the transport and deposition of high-energy rays; obtaining the ionization source term of high-energy rays in the atmosphere; substituting it into the ionization recombination equation; and solving for the density of each component of the atmospheric plasma after the nuclear explosion.

[0014] Furthermore, in step 1: the high-energy rays include transient emission rays and slow emission rays, wherein the slow emission rays originate from the decay of the debris cloud.

[0015] Further, step 2 specifically involves: obtaining the initial state of the debris cloud; based on the high-altitude environmental information and the density of each component of the atmospheric plasma obtained in step 1, solving the motion equations containing collision terms and electromagnetic interaction terms to obtain the motion state of the debris cloud, and then obtaining the density distribution of the debris cloud and the atmospheric deposition energy.

[0016] Further, step 4 specifically involves: using the updated atmospheric deposition energy as the initial driving source, and based on the updated density of each component of the atmospheric plasma, obtaining the atmospheric plasma velocity distribution information by solving the fluid motion equations containing electromagnetic and collision terms.

[0017] Further, step 5 specifically involves: based on the updated atmospheric plasma component densities, the atmospheric plasma velocity distribution information obtained in step 4, and the upper-altitude environment information, obtaining the electromagnetic field distribution information by solving the electromagnetic field equations containing magnetic induction source terms and conductors.

[0018] A calculation system for the spatial distribution of electromagnetic fields in late nuclear electromagnetic pulses is provided to realize the above-mentioned calculation method for the spatial distribution of electromagnetic fields in late nuclear electromagnetic pulses. Its special feature is that it includes an atmospheric ionization module, a debris cloud motion module, an atmospheric plasma motion module, and a low-frequency electromagnetic field propagation module.

[0019] The input terminal of the atmospheric ionization module is connected to the first output terminal of the debris cloud motion module, and its first output terminal is connected to the first input terminal of the low-frequency electromagnetic field propagation module. The second output terminal is connected to the input terminal of the debris cloud motion module and the first input terminal of the atmospheric plasma motion module, respectively. The atmospheric ionization module is used to calculate the atmospheric ionization effect based on the upper-air environment information, the energy spectrum of high-energy rays generated by the nuclear explosion, and the density distribution of the debris cloud, so as to obtain the density of each component of the atmospheric plasma after the nuclear explosion.

[0020] The second output terminal of the debris cloud motion module is connected to the second input terminal of the atmospheric plasma motion module. The debris cloud motion module is used to calculate the movement of debris clouds based on upper-altitude environmental information, debris cloud status, and the density of each component of atmospheric plasma after a nuclear explosion, to obtain the density distribution of debris clouds and atmospheric deposition energy, and to update the density distribution of debris clouds and atmospheric deposition energy.

[0021] The output end of the atmospheric plasma motion module is connected to the second input end of the low-frequency electromagnetic field propagation module; the atmospheric plasma motion module is used to calculate atmospheric motion based on high-altitude environmental information, the density of each component of atmospheric plasma after nuclear explosion and atmospheric deposition energy, and to obtain the atmospheric plasma velocity distribution.

[0022] The low-frequency electromagnetic field propagation module is used to calculate the electromagnetic field based on high-altitude environmental information, the density of each component of atmospheric plasma after the nuclear explosion, and the atmospheric plasma velocity distribution, so as to obtain the spatial distribution of the electromagnetic field of the late electromagnetic pulse.

[0023] The beneficial effects of this invention are:

[0024] The method provided by this invention can calculate the spatial distribution of the electromagnetic field of a late-stage nuclear electromagnetic pulse, reflecting the influence of explosion parameters and environmental parameters on the electromagnetic field, making its practical application more certain. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of an embodiment of the computational system for the spatial distribution of electromagnetic fields in late-stage nuclear electromagnetic pulses according to the present invention.

[0026] Figure 2 This is a flowchart of an embodiment of the method for calculating the spatial distribution of electromagnetic fields in late-stage nuclear electromagnetic pulses according to the present invention;

[0027] Figure 3This is a graph showing the variation of ray deposition energy with height in the projection direction of the explosion center in this embodiment of the invention;

[0028] Figure 4 This is a diagram showing the relative density distribution of the debris cloud on the meridional plane at 0.5s.

[0029] Figure 5 This is a comparison chart of the measured and calculated values ​​of the disturbed magnetic field test in an embodiment of the present invention;

[0030] Figure 6 This is a distribution diagram of the ground electric field of the late nuclear electromagnetic pulse at 40s in an embodiment of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1 As shown in the figure, this embodiment provides a calculation system for the spatial distribution of electromagnetic fields in late-stage nuclear electromagnetic pulses, including an atmospheric ionization module, a debris cloud motion module, an atmospheric plasma motion module, and a low-frequency electromagnetic field propagation module. The input terminal of the atmospheric ionization module is connected to the first output terminal of the debris cloud motion module, and its first output terminal is connected to the first input terminal of the low-frequency electromagnetic field propagation module. Its second output terminal is connected to both the input terminal of the debris cloud motion module and the first input terminal of the atmospheric plasma motion module. The atmospheric ionization module is used to calculate atmospheric ionization effects. The second output terminal of the debris cloud motion module is connected to the second input terminal of the atmospheric plasma motion module. The debris cloud motion module is used to calculate debris cloud motion. The output terminal of the atmospheric plasma motion module is connected to the second input terminal of the low-frequency electromagnetic field propagation module. The atmospheric plasma motion module is used to calculate atmospheric motion. The low-frequency electromagnetic field propagation module is used to calculate electromagnetic fields.

[0033] Based on the above system, the method for calculating the spatial distribution of the electromagnetic field of a late nuclear electromagnetic pulse provided by this embodiment of the invention includes the following steps:

[0034] Step 1. Calculate the atmospheric ionization effect after the nuclear explosion to obtain the density of each component of the atmospheric plasma. The input conditions required for this calculation include upper-altitude environmental information such as the atmospheric and geomagnetic environment, as well as the energy spectrum of high-energy rays generated by the nuclear explosion. These high-energy rays include transient emission lines and slow emission lines, with the slow emission lines originating from the decay of debris clouds. The density distribution information of the debris clouds provided by the debris cloud motion calculation module needs to be input. The transport and deposition of high-energy rays are calculated from the input conditions to obtain the ionization source term of high-energy rays in the atmosphere. Substituting this into the ionization recombination equation yields the composition of the atmospheric plasma and its density distribution change rate.

[0035] Step 2. Calculate the debris cloud motion to obtain the density distribution of the debris cloud and the distribution of atmospheric deposition energy. This calculation requires input information such as the initial debris cloud state and upper-level environment, as well as the density of each component of atmospheric plasma provided by the atmospheric ionization module.

[0036] Because the density of debris clouds is extremely low, collisions between them can be ignored, and only the collisions between debris clouds and the atmosphere need to be considered. Furthermore, since debris clouds are charged, their interaction with electromagnetic fields must also be considered. By solving the equations of motion containing collision and electromagnetic interaction terms, the motion state of the debris clouds can be obtained, and thus the density distribution of the debris clouds and the atmospheric deposition energy can be derived.

[0037] Step 3. Replace the initial fragment cloud density distribution in Step 1 with the fragment cloud density distribution obtained in Step 2, repeat Step 1, then update the initial fragment cloud state, repeat Step 2, and obtain the updated atmospheric plasma component densities and atmospheric deposition energy.

[0038] Step 4. Calculate atmospheric motion to obtain atmospheric plasma velocity distribution information. This calculation requires the final atmospheric deposition internal energy provided by the debris cloud motion module as the initial driving source, and also requires information such as the density of each component of atmospheric plasma and the upper-level environment provided by the atmospheric ionization module. Atmospheric plasma is subjected to electromagnetic forces and collisions with the neutral atmosphere. By solving the fluid motion equations containing electromagnetic and collision terms, the atmospheric plasma velocity distribution information can be obtained.

[0039] Step 5. Calculate the low-frequency electromagnetic field to obtain its spatial distribution. This calculation requires input from the atmospheric ionization module (densities of each component of atmospheric plasma) and the atmospheric plasma velocity distribution and upper-altitude environmental information from the atmospheric plasma motion module. Both atmospheric plasma and the Earth are conductors, affecting the electromagnetic field distribution; plasma motion is the excitation source term of the electromagnetic field. By solving the electromagnetic field equations containing the source term and the conductor, the spatiotemporal distribution of the electromagnetic field can be obtained.

[0040] Step 6. Based on the continuous iteration of steps 1-3, continuously repeat steps 4-5 until the preset calculation time is reached to obtain the final electromagnetic field distribution information. The electromagnetic field on the ground is the electromagnetic field of the late nuclear electromagnetic pulse.

[0041] The following section uses the US Starfish high-altitude nuclear explosion test as an example to elaborate on the calculation method for the aforementioned late-stage nuclear electromagnetic pulse. Data exchange relationships can be found in [reference needed]. Figure 1 The steps can be referred to Figure 2 The specific steps include:

[0042] Step 1: Data initialization, generating initial X-ray energy spectrum, fragment velocity spectrum, etc. Specifically, in this embodiment, the explosion altitude is 400km, the location is John Island at 17°N latitude, and the yield is 1400kT. The corresponding X-ray energy spectrum is a blackbody spectrum with a total energy of 70%; the fragment velocity spectrum is a Maxwell distribution with a total energy of 25%.

[0043] Step 2: Calculate the rate at which atmospheric plasma is generated by ionization of radiation. Instantaneous emission radiation generates plasma instantaneously, while slow emission radiation generates plasma over time. By tracing the path of the radiation and the atmospheric density along that path, the energy deposition of the radiation is calculated. Combined with the average ionization energy of atmospheric molecules, the generation rate of atmospheric plasma is obtained. Figure 3 The variation of ray deposition energy along the projection direction of the explosion center with height is given.

[0044] Step 3: Using the source terms calculated in Step 2, and combining them with the ionization recombination equation, calculate the evolution of atmospheric plasma to further obtain the density distribution of atmospheric plasma.

[0045] Step 4: Calculate the motion of the debris cloud under atmospheric collision drag and electromagnetic force. Specifically, in this embodiment, due to the high explosion altitude and long path of freedom of the debris cloud, the PIC method is used to solve the equation of motion of the debris cloud to obtain its density distribution. The work done by atmospheric collision drag is the kinetic energy deposition of the debris. Figure 4 The relative density distribution of the debris cloud on the meridional plane at 0.5s is given. As can be seen from the figure, the downward-moving debris cloud is basically distributed along the magnetic field lines of the Earth's magnetic field and eventually deposited in the atmosphere at an altitude of about 110km. Near the burst point, due to the presence of large magnetic bubbles, the debris cloud is dispersed near the magnetic bubbles.

[0046] Step 5: Using the kinetic energy deposition of debris as the driving source of atmospheric plasma motion, calculate the motion of atmospheric plasma by solving the fluid motion equations, and update the motion velocity and density distribution of atmospheric plasma.

[0047] Step 6: Obtain the driving source term of the electromagnetic field equation based on the velocity of the atmospheric plasma; update the spatial distribution of conductor conductivity based on the plasma density distribution. On this basis, solve the electromagnetic field equation to obtain the spatial distribution of the electromagnetic field of the late electromagnetic pulse. Figure 5 A comparison between the experimentally measured and calculated values ​​of the disturbed magnetic field is given, showing that the two values ​​are basically in agreement. In the figure, PB, DB, and HS represent the three peaks of the waveform. Figure 6 This refers to the distribution of the ground electric field of the late nuclear electromagnetic pulse at 40 seconds, obtained through this embodiment.

[0048] Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

Claims

1. A method for calculating the spatial distribution of electromagnetic fields in late-stage nuclear electromagnetic pulses, characterized in that, Includes the following steps: Step 1: Obtain information on the upper-air environment, the energy spectrum of high-energy rays generated by the nuclear explosion, and the density distribution of the initial debris cloud; perform atmospheric ionization effect calculations to obtain the density of each component of the atmospheric plasma after the nuclear explosion. Step 2: Obtain the initial debris cloud state. Based on the high-altitude environmental information and the density of each component of atmospheric plasma obtained in Step 1, perform debris cloud motion calculations to obtain the density distribution of the debris cloud and atmospheric deposition energy. Step 3: Replace the initial fragment cloud density distribution in Step 1 with the fragment cloud density distribution obtained in Step 2, repeat Step 1, then update the initial fragment cloud state, repeat Step 2, and obtain the updated atmospheric plasma component densities and atmospheric deposition energy. Step 4: Using the updated atmospheric deposition energy as the initial driving source, atmospheric motion calculations are performed based on the upper-air environment information and the updated atmospheric plasma component densities to obtain atmospheric plasma velocity distribution information. Step 5: Based on the updated atmospheric plasma component densities, the atmospheric plasma velocity distribution information obtained in Step 4, and the upper-altitude environment information, the electromagnetic field distribution information is obtained by solving the electromagnetic field equations containing magnetic induction source terms and conductors. Step 6: Based on the continuous iteration of steps 1-3, repeat steps 4-5 until the preset calculation time is reached to obtain the final electromagnetic field distribution information, which is the spatial distribution of the electromagnetic field of the late electromagnetic pulse.

2. The method for calculating the spatial distribution of the electromagnetic field of a late-stage nuclear electromagnetic pulse according to claim 1, characterized in that, Step 1 specifically involves: acquiring information about the upper-air environment, the energy spectrum of high-energy rays generated by the nuclear explosion, and the density distribution of the initial debris cloud; calculating the transport and deposition of high-energy rays; obtaining the ionization source term of high-energy rays in the atmosphere; substituting it into the ionization recombination equation; and solving for the density of each component of the atmospheric plasma after the nuclear explosion.

3. The method for calculating the spatial distribution of the electromagnetic field of a late-stage nuclear electromagnetic pulse according to claim 2, characterized in that, In step 1: the high-energy rays include transient emission rays and slow emission rays, wherein the slow emission rays originate from the decay of the debris cloud.

4. The method for calculating the spatial distribution of the electromagnetic field of a late-stage nuclear electromagnetic pulse according to claim 1, 2, or 3, characterized in that, Step 2 specifically involves: obtaining the initial state of the debris cloud; based on the high-altitude environmental information and the density of each component of the atmospheric plasma obtained in Step 1, solving the motion equations containing collision terms and electromagnetic interaction terms to obtain the motion state of the debris cloud, and then obtaining the density distribution of the debris cloud and the atmospheric deposition energy.

5. The method for calculating the spatial distribution of the electromagnetic field of a late-stage nuclear electromagnetic pulse according to claim 4, characterized in that, Step 4 specifically involves: using the updated atmospheric deposition energy as the initial driving source, and based on the updated density of each component of the atmospheric plasma, obtaining the atmospheric plasma velocity distribution information by solving the fluid motion equations containing electromagnetic and collision terms.

6. A calculation system for the spatial distribution of electromagnetic fields in late-stage nuclear electromagnetic pulses, used to implement the calculation method for the spatial distribution of electromagnetic fields in late-stage nuclear electromagnetic pulses as described in any one of claims 1-5, characterized in that: This includes an atmospheric ionization module, a debris cloud motion module, an atmospheric plasma motion module, and a low-frequency electromagnetic field propagation module; The input terminal of the atmospheric ionization module is connected to the first output terminal of the debris cloud motion module, and its first output terminal is connected to the first input terminal of the low-frequency electromagnetic field propagation module. The second output terminal is connected to the input terminal of the debris cloud motion module and the first input terminal of the atmospheric plasma motion module, respectively. The atmospheric ionization module is used to calculate the atmospheric ionization effect based on the upper-air environment information, the energy spectrum of high-energy rays generated by the nuclear explosion, and the density distribution of the debris cloud, so as to obtain the density of each component of the atmospheric plasma after the nuclear explosion. The second output terminal of the debris cloud motion module is connected to the second input terminal of the atmospheric plasma motion module. The debris cloud motion module is used to calculate the movement of debris clouds based on upper-altitude environmental information, debris cloud status, and the density of each component of atmospheric plasma after a nuclear explosion, to obtain the density distribution of debris clouds and atmospheric deposition energy, and to update the density distribution of debris clouds and atmospheric deposition energy. The output end of the atmospheric plasma motion module is connected to the second input end of the low-frequency electromagnetic field propagation module; the atmospheric plasma motion module is used to calculate atmospheric motion based on high-altitude environmental information, the density of each component of atmospheric plasma after nuclear explosion and atmospheric deposition energy, and to obtain the atmospheric plasma velocity distribution. The low-frequency electromagnetic field propagation module is used to calculate the electromagnetic field based on high-altitude environmental information, the density of each component of atmospheric plasma after the nuclear explosion, and the atmospheric plasma velocity distribution, so as to obtain the spatial distribution of the electromagnetic field of the late electromagnetic pulse.

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