A method for obtaining the surface charging potential of a high-vacuum celestial body without intrinsic magnetic field.

Abstract

This application provides a method for obtaining the charging potential of a high-vacuum celestial body surface without an intrinsic magnetic field, comprising: deploying plasma and charged particle detection instruments at specific points on the celestial body surface and on a spacecraft to acquire observational data of plasma and charged particles at the specific points on the celestial body surface and along the spacecraft's trajectory; calculating the charging potential at the specific points on the celestial body surface; establishing a model of the surface charging potential at the specific points on the celestial body; using a fitting method to obtain a quantitative relationship between the observational data of the peak flux of plasma and charged particles in each direction of the total energy spectrum measured by the upstream spacecraft and the specific points on the celestial body surface; and substituting the quantitative relationship into the surface charging potential model at the specific points on the celestial body to establish a model of the celestial body surface charging potential. The advantage of this application is that it can establish a model of the charging potential of a high-vacuum celestial body surface without an intrinsic magnetic field using only the observational data of plasma and charged particles from the upstream spacecraft as input data.

Description

Technical Field

[0001] This application belongs to the technical fields of aerospace science, planetary science, and obtaining the surface charge state of celestial bodies (such as the moon, asteroids, etc.) in high vacuum environments without intrinsic magnetic fields. Specifically, it relates to a method for obtaining the charging potential of the surface of a celestial body in high vacuum without intrinsic magnetic fields. Background Technology

[0002] Celestial bodies lacking intrinsic magnetic fields but possessing high-vacuum atmospheric environments are widespread, such as the Moon, small solar system bodies, and icy moons of Jupiter like Europa, making them popular targets for solar system exploration. On the surfaces of these celestial bodies without intrinsic magnetic fields and possessing high-vacuum atmospheric environments, the lack of an atmosphere and magnetic field protection allows external environmental factors such as plasma and cosmic rays to directly bombard their surfaces. Under the combined influence of solar radiation, plasma, and charged particles from cosmic rays, charge accumulates on the celestial surface, creating a potential difference relative to the background plasma environment. As the amount of accumulated charge increases, it can cause significant charging phenomena over a large area of ​​the celestial surface, with varying charging amplitudes depending on the location on the surface. If a discharge event occurs, it will affect the safety of equipment and organisms deployed on the celestial surface. Especially when observation stations on the celestial surface are distributed over a large area, assessing the variation amplitude and peak intensity of charging potential at different locations on the celestial surface is of great significance.

[0003] Currently, there are two types of potential measurement methods applicable to celestial surfaces. One type uses a probe to measure the relative potential difference between two points, but the measurement range is limited by the size of the probe, only reflecting small-scale relative potential changes near the location of the device. The other type uses short-term perturbations in plasma detection data of the celestial surface during periods of calm in the space environment to calculate the potential change at that point. However, these methods only reflect potential changes in small areas of the celestial surface and cannot yet be applied to assess the charging status of different regions over a larger area of ​​the celestial surface. Summary of the Invention

[0004] The purpose of this application is to overcome the limitation of existing technologies in terms of measurement range, which makes them unsuitable for evaluating the charging status of different regions over a large area on the surface of celestial bodies.

[0005] To achieve the above objectives, this application proposes a method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field, comprising:

[0006] Step 1: Deploy plasma detection instruments and charged particle detection instruments at specific points on the surface of a high-vacuum celestial body without an intrinsic magnetic field and on a spacecraft operating in the same plasma region upstream of the celestial body to obtain observational data on plasma and charged particles at specific points on the celestial body's surface and along the spacecraft's trajectory.

[0007] Step 2: Calculate the charging potential at a specific point on the surface of the celestial body based on the perturbation of plasma data during a specific time period;

[0008] Step 3: Combining the observational data of plasma and charged particles at specific points on the surface of a celestial body, and the observed values ​​of the charging potential at specific points on the surface of a celestial body, establish a model of the surface charging potential at specific points on the celestial body based on the current balance equation and parameter calculation formula.

[0009] Step 4: Using a fitting method, obtain the quantitative relationship between the observation data of the peak flux of plasma and charged particles in each direction of the energy spectrum at specific points on the upstream spacecraft and the celestial surface;

[0010] Step 5: Substitute the quantitative relationship into the surface charging potential model of a specific point on the celestial body to establish a high-vacuum celestial body surface charging potential model without intrinsic magnetic field, so as to realize the calculation of the charging potential of the measured area on the celestial body surface at any time based on the observation of plasma and charged particles by the upstream spacecraft.

[0011] As an improvement to the above method, when experiencing the solar wind, the upstream of the celestial body refers to the side closer to the sun on the orbit between the celestial body and the sun; when experiencing the planetary magnetosphere, the upstream of the celestial body refers to the side closer to the planet on the orbit between the planet and the celestial body.

[0012] As an improvement to the above method, the observation data of plasma and charged particles at specific points on the surface of a celestial body and along the trajectory of the spacecraft includes energy spectral flux data.

[0013] As an improvement to the above method, plasma detection instruments, if they pass through the solar wind, have the ability to detect the solar wind; if they pass through the planetary magnetosphere, they have the ability to measure the plasma in the planetary magnetosphere.

[0014] For high-energy charged particle detectors, they have the ability to detect high-energy charged particles, and the detection targets include planetary radiation belts and solar cosmic rays that the target passes through.

[0015] As an improvement to the above method, the specific time period includes:

[0016] When a celestial body is moving in the solar wind, there are periods without solar high-energy proton events or coronal mass ejection events; when a celestial body is moving in the planetary magnetosphere, there are periods without space environment disturbances that could cause the overall plasma energy spectrum to rise or fall by more than 10% of its central velocity.

[0017] As an improvement to the above method, the calculation of the charging potential at a specific point on the surface of a celestial body is performed when the celestial body is moving in the solar wind, the charging potential V g The calculation formula is:

[0018] V g =E-E0 / Q

[0019] Where E represents the energy value corresponding to the peak velocity at the center of the solar wind; E0 represents the energy value corresponding to the peak velocity at the center of the solar wind before the perturbation at the corresponding moment; and Q represents the charge number of the solar wind plasma.

[0020] When a celestial body is orbiting in a planetary magnetosphere, the charging potential V g The calculation formula is:

[0021] V g =E'-E0' / Q'

[0022] Where E' represents the energy value corresponding to the peak velocity at the center of the planetary magnetospheric plasma; E0' represents the energy value corresponding to the peak velocity at the center of the planetary magnetospheric plasma before the perturbation at the corresponding moment; and Q' represents the charge number of the planetary magnetospheric plasma.

[0023] As an improvement to the above method, the current balance equation and parameter calculation formula include:

[0024] J V +J I +J E +J B +J SEC =0

[0025] J SECE =Y SE J E

[0026] J SECI =Y SI J I

[0027] Y SE =2.228 d m (Q E -1+ (E) m / E) 0.35 / Q E

[0028] Y SI =(2-Q I / 2) Y1 / (1+E / E m )

[0029] J B =Y BE (J E +Y BI JI )

[0030] When the Debye radius is greater than or equal to the characteristic size of the celestial body:

[0031] J E =J E0 (1+eU / E)

[0032] J I =J I0 (1-eU / E)

[0033] When the Debye radius is less than the characteristic size of the celestial body:

[0034] J E =J E0 (1+eU / E), U<0; J E =J E0 U≥0

[0035] J I =J I0 (1-eU / E), U>0; J I =J I0 ,U≤0

[0036] Among them, J V Photocurrent; J I J is the ion current density; E J is the electron current density; B J is the backscattering current density; SEC The second electron current density is given by e; the unit charge is given by J. E0 J is the incident electron current density with energy E; I0 The incident ion current density is E; U is the surface potential of the celestial body; J SECE Y is the secondary electron current density of the incident electrons; SE J is the secondary generation rate of the incident electron; SECI Y is the secondary electron current density of the incident proton; SI Y represents the secondary production rate of the incident protons. BE and Y BI These are the reflection coefficients of ions and electrons reflected from the surface of a celestial body, respectively. d m Q represents the rate of production of the maximum number of secondary electrons generated by the incident electron. E =2.28(Em / E) 1.35 E m The incident electron energy that produces the maximum incident rate; Q I =1 / E-0.1; Y1 is the production rate of incident protons with energy of 1 keV; E m The incident electron energy that produces the incident proton with the maximum incident rate.

[0037] As an improvement to the above method, the quantitative relationship between the observation data of the peak flux of plasma and charged particles in each direction of the energy spectrum measured by the upstream spacecraft and specific points on the surface of the celestial body is expressed as a function F(Φ) of the angle Φ between the field of view center perpendicular to the specific point on the surface of the celestial body and the velocity center of the incident plasma or charged particles.

[0038] As an improvement to the above method, when the celestial body to be measured is the Moon, the field of view Φ is the angle between the direction of the central flux of charged particles and the line connecting each point on the lunar surface to the center of the Moon; during a period of quiet solar activity, data from multiple rotation cycles are acquired, averaged point by point, and fitted to obtain the quantitative relationship function F(Φ).

[0039] As an improvement to the above method, when the celestial body under test is not the Moon, the quantitative relationship between the observation data of the peak flux of plasma and charged particles in each direction of the energy spectrum measured by the upstream spacecraft and specific points on the surface of the celestial body is adopted using the quantitative relationship calculated by the Moon. The measured data of plasma and charged particles on the orbiter of the celestial body are used as the upstream observation data to achieve a rough estimate of the charging potential at different positions and times on the surface of the celestial body.

[0040] Compared with existing technologies, the advantages of this application are:

[0041] Plasma and charged particle detectors are widely used in the Sun-Earth space, and these payloads are usually the preferred scientific probes carried on spacecraft and landers. These devices can not only acquire local plasma and charged particle detection data, but plasma observation devices on landers can also calculate the surface charging potential of observation points on satellites or celestial bodies during periods of calm space environment. However, these devices have difficulty calculating the charging potential during periods of space environment disturbance.

[0042] This invention utilizes this type of payload to not only solve the current problem of lacking a method for simultaneously acquiring the surface charging potential at different locations on a celestial body at any given time, thus enabling convenient acquisition of the surface charging potential at different locations and providing support for aerospace equipment and extraterrestrial survival, but also achieves high cost-effectiveness by avoiding the resource waste of deploying a large number of potential detection payloads on the surface. This invention has broad application potential in the field of exploring high-vacuum celestial bodies without intrinsic magnetic fields, such as the Moon.

[0043] The method provided by this invention for obtaining the charging potential of different regions on the surface of a high-vacuum celestial body without an intrinsic magnetic field only requires launching a plasma and charged particle detector at a specific point near the celestial body surface once. Combined with observation data from multiple upstream spacecraft carrying plasma and charged particle detectors, a model of the charging potential of a high-vacuum celestial body without an intrinsic magnetic field can be established using only the plasma and charged particle observation data from upstream spacecraft as input data. This model can be used to calculate and determine the surface charging potential of a celestial body at different times and at different locations globally. Attached Figure Description

[0044] Figure 1 The diagram shows a flowchart of a method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field. Detailed Implementation

[0045] The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0046] This invention provides a method for obtaining the charging potential of the surface of a high-vacuum celestial body without an intrinsic magnetic field. The method includes the following steps: deploying plasma and charged particle observation instruments at specific points on the surface of the high-vacuum celestial body without an intrinsic magnetic field and on a spacecraft operating in a plasma environment similar to that upstream of the celestial body; acquiring observation data of plasma and charged particles at the specific points on the celestial body surface and along the trajectory of the spacecraft; calculating the charging potential of the specific points on the celestial body surface based on the perturbation of plasma data at a specific time period; and calculating the charging potential based on the observation data of plasma and charged particles at the specific points on the celestial body surface and the... The charging potential at a specific point on the surface of a celestial body can be used to establish a charging potential model for that specific point on the celestial body's surface. A quantitative relationship can be obtained between the observational data of the peak flux of the total energy spectrum of plasma and charged particles measured by the upstream spacecraft and the specific point on the celestial body's surface at different angles between the field of view center of the specific point on the celestial body's surface and the velocity center of the incident plasma or charged particles. This quantitative relationship can then be substituted into the charging potential model of the celestial body's surface at the specific point to establish a charging potential model for a high-vacuum celestial body without an intrinsic magnetic field, which can be used to calculate and determine the charging potential at different locations on the celestial body's surface.

[0047] The method for obtaining the charging potential of different regions on the surface of a high-vacuum celestial body without an intrinsic magnetic field is as follows:

[0048] Step 1: Deploy plasma and charged particle observation instruments at specific points on the surface of a high-vacuum celestial body without an intrinsic magnetic field and on a spacecraft operating in the same plasma region upstream of the celestial body (if it is experiencing solar wind, upstream refers to the orbit between the celestial body and the sun, closer to the sun; if it is a planetary magnetosphere, upstream refers to the orbit between the planet and the celestial body, closer to the planet). Obtain observation data (energy spectrum flux data, etc.) of plasma and charged particles at specific points on the celestial body surface and along the trajectory of the spacecraft.

[0049] Specific points on the surface of a celestial body are one or more points within the area to be tested on that celestial body's surface.

[0050] Among them, plasma detection instruments should be able to detect solar wind if they pass through the solar wind, and should be able to measure planetary magnetospheric plasma if they pass through the planetary magnetosphere.

[0051] For charged particle detectors, they should have the ability to detect charged particles, mainly electrons with energies below MeV. The detection targets include planetary radiation belts and solar cosmic rays that the target passes through.

[0052] For the Moon, where the trajectory passes through both the solar wind and the Earth's magnetosphere, plasma observations deployed on the lunar surface should be able to acquire the flux spectra of both the solar wind and the Earth's magnetosphere. For high-energy charged particles, the instruments should be capable of detecting high-energy solar particles, taking into account the lunar environment. Upstream plasma and high-energy particle data can be obtained using synchronous observation data from relay satellites, orbiters, or other existing satellites in the Sun-Earth space relatively close to the Moon. If the planned landing area is located in the high-latitude polar region of the Moon, plasma and high-energy charged particle observation instruments can be deployed in that region without needing to select other special locations.

[0053] Step 2: Calculate the charging potential at a specific point on the surface of the celestial body based on the perturbation of plasma data during a specific time period;

[0054] A specific time period refers to a period when a celestial body is traveling in the solar wind without bursts of solar activity such as high-energy proton events or coronal mass ejections; or when a celestial body is traveling in a planetary magnetosphere without geomagnetic storms or other space environment disturbances that could cause an overall increase or decrease in the plasma energy spectrum exceeding 10% of its central velocity. Whether a space environment is disturbed is not defined by specific data; it is defined based on whether a certain type of event occurs. These events each have their own definitions.

[0055] Using time-continuous plasma energy spectrum data obtained from observations, for solar wind plasma, the moment when the relatively gently changing solar wind center velocity (the velocity corresponding to the flux peak of the energy spectrum data at each sampling moment) suddenly rises / falls should be selected as the moment of the charging event. At this time, the difference between the energy value E corresponding to the peak solar wind center velocity and the energy value E0 corresponding to the peak solar wind center velocity before the perturbation, divided by the charge number Q of the solar wind plasma, is the charging potential V. g .

[0056] V g =E-E0 / Q

[0057] When passing through a planetary magnetosphere, the formula for the charging potential is the same as the one above. The difference is that E represents the energy value corresponding to the peak velocity at the center of the planetary magnetosphere plasma; E0 represents the energy value corresponding to the peak velocity at the center of the planetary magnetosphere plasma before the disturbance at that moment; and Q represents the charge number of the planetary magnetosphere plasma.

[0058] Step 3: Combining observational data of plasma and charged particles at specific points on the celestial body's surface, and observational values ​​of the charging potential at those specific points, establish a model of the surface charging potential at a specific point on the celestial body based on the following current balance equations and parameter calculation formulas:

[0059] The choice of which formula to use depends on the Debye radius of the plasma and the characteristic size of the celestial body. If the Debye radius is greater than or equal to the characteristic size of the celestial body, then the following formula should be used:

[0060] J V +J I +J E +J B +J SEC =0 (1)

[0061] J E =J E0 (1+eU / E) (2)

[0062] J I =J I0 (1-eU / E) (3)

[0063] J SECE =Y SE J E (4)

[0064] J SECI =Y SI J I (5)

[0065] Y SE =2.228 d m (QE -1+ (E) m / E) 0.35 / Q E (6)

[0066] Y SI =(2-Q I / 2) Y1 / (1+E / E m1 (7)

[0067] J B =Y BE (J E +Y BI J I (8)

[0068] J V For photocurrent, J I J is the ion current density. E J is the electron current density. B J is the backscattering current density. SEC Let J be the secondary electron current density, e be the unit charge, and J be the total charge. E0 The incident electron current density with energy E, J I0 The incident ion current density with energy E, U is the surface potential of the celestial body, and J is the energy of the incident ion current density. SECE Y is the secondary electron current density of the incident electrons. SE It is the secondary generation rate of the incident electron, J SECI It is the secondary electron current density of the incident proton, Y SI Y is the secondary production rate of the incident protons. BE and Y BI These are the reflection coefficients of ions and electrons reflected from the surface of a celestial body, respectively. In equation (6), d m The rate of production of the maximum number of secondary electrons generated by the incident electron, Q E =2.28(Em / E) 1.35 E m It is the incident electron energy that produces the maximum incident rate, in equation (7), Q I =1 / E-0.1, where Y1 is the production rate of incident protons with energy of 1 keV, and E m1 It is the incident energy of the incident proton that produces the maximum incident rate.

[0069] If the Debye radius is less than the characteristic size of the celestial body, then equations (2) and (3) should be replaced by the following formulas:

[0070] J E =J E0 (1+eU / E),U<0

[0071] J E =J E0 ,U≥0 (2)

[0072] J I =J I0 (1-eU / E), U>0

[0073] J I =J I0 ,U≤0 (3)

[0074] For the Moon, a formula can be used where the Debye radius is much larger than the characteristic size of the celestial body. The average value of the lunar photocurrent can be chosen as 50 microamps per square meter; the average value of the reflection coefficient of the solar wind plasma current can be chosen as 20%.

[0075] Step 4: Using a fitting method, obtain the quantitative relationship between the peak flux data of plasma and charged particles in each energy spectrum measured at specific points on the upstream spacecraft and the celestial surface. This quantitative relationship can be expressed as a function F(Φ) of the angle Φ between the field of view center perpendicular to the specific point on the celestial surface and the velocity center of the incident plasma or charged particles. The ion and electron currents at the specific point on the celestial surface can be calculated using F(Φ). The selection method for the peak flux in each energy spectrum is as follows: for plasma, the maximum value among the flux data in each energy spectrum across all directions is selected; for charged particles, the maximum value of the flux data in each energy band across all directions is selected.

[0076] The method for selecting the peak value of the total directional flux in the energy spectrum is as follows:

[0077] For plasma, the peak value of the total directional flux is the maximum value among the flux data of all directions of the observed data:

[0078] F max =max(Σ E Σ ang F Ef_ang )

[0079] Among them, F Ef_ang It contains flux data from different energy bands and at different angles;

[0080] For charged particles, the peak value of the total directional flux in the energy spectrum is the maximum value of the flux data in all directions across different energy ranges:

[0081] F E_max =max(Σ ang F Ef_ang )

[0082] For the Moon, data from multiple rotation cycles can be obtained during periods of quiet solar activity, averaged point by point, and fitted to obtain the quantitative relationship function F(Φ). Based on F(Φ), the particle flux received by different regions of the celestial body can be calculated.

[0083] Step 5: Substitute the quantitative relationship F(Φ) into the celestial surface charging potential model at a specific point to establish a high-vacuum celestial surface charging potential model without intrinsic magnetic field, so as to achieve the goal of calculating the charging potential at any point on the celestial surface at any time based on the observation of plasma and charged particles by upstream spacecraft.

[0084] For the moon, assuming it is circular, the field of view Φ can be regarded as the angle between the central flux direction of charged particles and the line connecting each point on the lunar surface to the center of the moon.

[0085] Currently, there is a considerable amount of observational data available for the Moon, which can be used to establish a surface charging model using this method. However, no landing observations have been conducted on other similar celestial bodies. This method can be extended to roughly estimate the charging potential at any point on the surface of a high-vacuum celestial body without an intrinsic magnetic field at any given time by adding additional assumptions. The method is as follows: assuming that the quantitative relationship between the celestial body's surface and upstream observational data can be directly adopted from the quantitative relationship calculated on the Moon, and using the measured data of plasma and charged particles on the orbiter of this celestial body as upstream observational data, a rough estimate of the charging potential at different locations and times on the celestial body's surface can be achieved.

[0086] This invention provides a method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field. This involves deploying plasma and charged particle observation instruments at specific points on the surface of the celestial body and on a spacecraft operating in a plasma environment similar to that upstream of the celestial body. Simultaneous observation data of plasma and charged particles at these specific points on the celestial body's surface and along the spacecraft's trajectory are obtained. Based on this simultaneous observation data, a quantitative relationship is obtained using a fitting method between the observation data of the peak flux of the total energy spectrum of plasma and charged particles at each direction during a relatively calm space environment, on the upstream spacecraft and at the specific point on the celestial body's surface. This quantitative relationship varies with the angle between the field of view center at the specific point on the celestial body's surface and the velocity center of the incident plasma or charged particles. This quantitative relationship can be used to calculate the amount of charge potential received by different regions of the celestial body. The particle flux is calculated; then, based on the perturbation of plasma data when the space environment is relatively calm, the charging potential at a specific point on the celestial surface is calculated; combining the observational data of plasma and charged particles at a specific point on the celestial surface, the charging potential at that specific point on the celestial surface, and the theoretical formulas related to surface charging, a charging potential model for that specific point on the celestial surface is established. This model can use the flux changes of plasma and charged particles as input parameters to calculate the charging potential at that point; by replacing the input parameters of the celestial surface charging potential model for a specific point with the quantitative relationship of particle flux in different regions calculated using upstream data mentioned above, a new celestial surface charging potential model without intrinsic magnetic field and only related to upstream plasma and charged particle data can be established, thereby realizing the calculation of charging potential at different locations on the celestial surface using the model. This method not only enables the acquisition of the charging potential at any point on the surface of such celestial bodies at any time, but it is also economically feasible. It only requires the deployment of plasma and charged particle observation instruments at specific points on the surface of the celestial body to obtain the quantitative relationship between the peak total flux of plasma and charged particles between the upstream solar wind and the observation point, as well as the charging model at the specific point. By substituting this quantitative relationship into the model to form a new charging potential model for the surface of the celestial body, it is possible to use plasma and charged particle observation data from other existing upstream satellites to obtain the charging potential values ​​of various regions on the surface of the celestial body.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application, and should all be covered within the scope of the claims of this application.

Claims

1. A method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field, comprising: Step 1: Deploy plasma detection instruments and charged particle detection instruments at designated points on the surface of a high-vacuum celestial body without intrinsic magnetic field and on a spacecraft operating in the same plasma region upstream of the celestial body to acquire observational data on plasma and charged particles at the designated points on the celestial body's surface and along the spacecraft's trajectory. Step 2: Calculate the charging potential at a set point on the surface of the celestial body based on the perturbation of plasma data during the set time period; Step 3: Combining the observation data of plasma and charged particles at a set point on the celestial body surface, and the observed values ​​of the charging potential at the set point on the celestial body surface, establish a surface charging potential model for the set point on the celestial body based on the current balance equation and parameter calculation formula. Step 4: Using a fitting method, obtain the quantitative relationship between the observation data of the peak flux of plasma and charged particles in each direction of the energy spectrum measured at designated points on the upstream spacecraft and the celestial surface; Step 5: Substitute the quantitative relationship into the surface charging potential model of the celestial body at the set point to establish a high-vacuum celestial body surface charging potential model without intrinsic magnetic field, so as to realize the calculation of the charging potential of the measured area on the celestial body surface at any time based on the observation of plasma and charged particles by the upstream spacecraft.

2. The method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field according to claim 1, characterized in that, When experiencing the solar wind, the upstream of a celestial body refers to the orbit between the celestial body and the sun, closer to the sun; when experiencing a planetary magnetosphere, the upstream of a celestial body refers to the orbit between the planet and the celestial body, closer to the planet.

3. The method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field according to claim 1, characterized in that, The observation data obtained from the acquisition of plasma and charged particles at a set point on the celestial surface and along the spacecraft's trajectory includes energy spectrum flux data.

4. The method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field according to claim 1, characterized in that: For plasma detection instruments, experiencing the solar wind enables them to detect the solar wind; experiencing planetary magnetospheres enables them to measure planetary magnetospheric plasma. For high-energy charged particle detectors, they have the ability to detect high-energy charged particles, and the detection targets include planetary radiation belts and solar cosmic rays that the target passes through.

5. The method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field according to claim 1, characterized in that, The set time period includes: When a celestial body is moving in the solar wind, there are no periods of solar high-energy proton events or coronal mass ejection events; when a celestial body is moving in the planetary magnetosphere, there are no periods of space environment disturbances that could cause the overall plasma energy spectrum to rise or fall by more than 10% of its central velocity.

6. The method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field according to claim 1, characterized in that, The calculation of the charging potential at a designated point on the surface of a celestial body is performed when the celestial body is moving in the solar wind, with the charging potential V... g The calculation formula is: V g =E-E0 / Q Where E represents the energy value corresponding to the peak velocity at the center of the solar wind; E0 represents the energy value corresponding to the peak velocity at the center of the solar wind before the perturbation at the corresponding moment; and Q represents the charge number of the solar wind plasma. When a celestial body is orbiting in a planetary magnetosphere, the charging potential V g The calculation formula is: V g =E'-E0' / Q' Where E' represents the energy value corresponding to the peak velocity at the center of the planetary magnetospheric plasma; E0' represents the energy value corresponding to the peak velocity at the center of the planetary magnetospheric plasma before the perturbation at the corresponding moment; and Q' represents the charge number of the planetary magnetospheric plasma.

7. The method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field according to claim 1, characterized in that, The current balance equation and parameter calculation formula include: J V +J I +J E +J B +J SEC =0 J SECE =Y SE J E J SECI =Y SI J I Y SE =2.228 δ m (Q E -1+ )(E m / E) 0.35 / Q E Y SI =(2-Q I / 2) Y1 / (1+E / E m1 ) J B =Y BE (J E +Y BI J I ) When the Debye radius is greater than or equal to the characteristic size of the celestial body: J E =J E0 (1+eU / E) J I =J I0 (1-eU / E) When the Debye radius is less than the characteristic size of the celestial body: J E =J E0 (1+eU / E),U<0;J E =J E0 ,U≥0 J I =J I0 (1-eU / E),U>0; J I =J I0 ,U≤0 Among them, J V Photocurrent; J I J is the ion current density; E Electron current density; J B J is the backscattering current density; SEC The second electron current density is given by e; the unit charge is given by J. E0 J is the incident electron current density with energy E; I0 The incident ion current density is E; U is the surface potential of the celestial body; J SECE Y is the secondary electron current density of the incident electrons; SE J is the secondary generation rate of the incident electron; SECI Y is the secondary electron current density of the incident proton; SI Y represents the secondary production rate of the incident protons. BE and Y BI These are the reflection coefficients of ions and electrons reflected from the surface of a celestial body, respectively. δ m Q represents the rate of production of the maximum number of secondary electrons generated by the incident electron. E =2.28(Em / E) 1.35 E m The incident electron energy that produces the maximum incident rate; Q I =1 / E-0.1; Y1 is the production rate of incident protons with energy of 1 keV; E m1 The incident energy is the incident proton that produces the maximum incident rate.

8. The method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field according to claim 1, characterized in that, The quantitative relationship between the observation data of the peak flux of plasma and charged particles in each direction of the energy spectrum measured by the upstream spacecraft and the set point on the celestial surface is expressed as a function F(Φ) of the angle Φ between the field of view center perpendicular to the set point on the celestial surface and the velocity center of the incident plasma or charged particle.

9. The method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field according to claim 8, characterized in that, When the celestial body to be measured is the Moon, the field of view Φ is the angle between the direction of the central flux of charged particles and the line connecting each point on the lunar surface to the center of the Moon. During a period of quiet solar activity, data from multiple rotation cycles are acquired, averaged point by point, and fitted to obtain the quantitative relationship function F(Φ).

10. The method for obtaining the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field according to claim 1, characterized in that, When the celestial body under test is not the Moon, the quantitative relationship between the observation data of the peak flux of plasma and charged particles in each direction of the energy spectrum measured by the upstream spacecraft and the set points on the surface of the celestial body is adopted. The quantitative relationship obtained by the Moon is used, and the measured data of plasma and charged particles on the orbiter of the celestial body is used as the upstream observation data to achieve a rough estimate of the charging potential at different positions and times on the surface of the celestial body.

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