Method for acquiring surface charging potential of intrinsic magnetic field-free high-vacuum celestial body

Abstract

The invention provides a method for acquiring the surface charging potential of a high-vacuum celestial body without an intrinsic magnetic field, and the method comprises the steps: arranging plasma and energy charged particle detection instruments at a specific point position of the surface of the celestial body and on a spacecraft, and obtaining the observation data of the plasma and energy charged particles at the specific point position of the surface of the celestial body and on the trajectory of the spacecraft; calculating the charging potential of a specific point on the surface of the celestial body; establishing a celestial body specific point position surface charging potential model; a fitting method is used for obtaining the quantitative relation between the energy spectrum total direction flux peak value observation data of plasmas and energy charged particles measured at specific point positions on the surfaces of the upstream spacecraft and the celestial body respectively; and substituting the quantitative relation into a celestial body specific point position surface charging potential model, and establishing a celestial body surface charging potential model. The method has the advantages that the intrinsic magnetic field-free high-vacuum celestial body surface charging potential model which only uses plasma and energy charged particle observation data of an upstream spacecraft as input data can be established.

Description

Technical Field

[0001] The present application belongs to the technical field of aerospace science, planetary science and obtaining the surface charge state of celestial bodies (such as the moon, asteroids, etc.) in a high vacuum environment without intrinsic magnetic field, and specifically relates to a method for obtaining the surface charge potential of a celestial body with high vacuum without intrinsic magnetic field. Background Art

[0002] Celestial bodies with no intrinsic magnetic field and high vacuum atmosphere are widely present, such as the moon, small solar system bodies, and icy satellites of Jupiter such as Europa, which are popular targets for solar system exploration. On the surface of such celestial bodies with no intrinsic magnetic field and high vacuum atmosphere, due to the loss of the protection of the atmosphere and magnetic field, plasma and cosmic rays in the external environment can directly bombard the surface of the celestial body. Under the combined effect of solar radiation, plasma, cosmic ray charged particles and other factors, electric charges accumulate on the surface of the celestial body, generating a potential difference relative to the background plasma environment. As the amount of accumulated charge increases, it may cause a large-scale charging phenomenon in a large area of ​​the celestial surface, and the charging amplitude is different at different locations on the celestial surface. If a discharge event occurs, it will affect the safety of equipment and organisms deployed on the celestial surface. Especially when the observation sites on the surface of the celestial body are distributed over a large range, it is of great significance to evaluate the variation amplitude and peak intensity of the charging potential at different locations on the surface of the celestial body.

[0003] There are currently two types of potential measurement methods that can be applied to the surface of celestial bodies. One is to use a probe to measure the relative potential difference between two points, but the measurement range is limited by the size of the probe and can only reflect the relative change of the small-scale potential near the point where the device is located; the other is to use the short-term disturbance of the plasma detection data on the surface of the celestial body during the period of calm space environment to calculate the change of the potential at that point. However, the above method only reflects the potential change of a small area on the surface of the celestial body, and cannot be used to evaluate the charging conditions of different areas on the surface of a celestial body over a large range. Summary of the invention

[0004] The purpose of this application is to overcome the defect that the existing technology has a limited measurement range and cannot be applied to evaluate the charging conditions of different areas over a large range on the surface of a celestial body.

[0005] In order to achieve the above purpose, the present application proposes a method for obtaining the surface charge potential of a high vacuum celestial body without intrinsic magnetic field, comprising:

[0006] Step 1: Plasma detection instruments and energetic charged particle detection instruments are deployed at specific points on the surface of a high-vacuum celestial body with no intrinsic magnetic field and on a spacecraft operating in the same plasma region upstream of the celestial body to obtain observation data of plasma and energetic charged particles at specific points on the surface of the celestial body and on the trajectory of the spacecraft;

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

[0008] Step 3: Combine the observation data of plasma and energetic charged particles at specific points on the surface of the celestial body with the observation value of the charging potential at specific points on the surface of the celestial body, and establish a surface charging potential model for specific points on the celestial body according to the current balance equation and parameter calculation formula;

[0009] Step 4: Use the fitting method to obtain the quantitative relationship between the peak values ​​of the total directional flux of plasma and energetic charged particles in each energy spectrum measured by the upstream spacecraft and the specific points on the surface of the celestial body;

[0010] Step 5: Substitute the quantitative relationship into the surface charging potential model of a specific point on the celestial body, establish a surface charging potential model for a high-vacuum celestial body with no intrinsic magnetic field, and calculate the charging potential of the surface area to be measured at any time based on the observation of plasma and energetic charged particles by upstream spacecraft.

[0011] As an improvement of the above method, when experiencing solar wind, the upstream of the celestial body refers to the side close 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 close to the planet between the planet and the celestial body.

[0012] As an improvement of the above method, in the acquisition of observation data of plasma and energetic charged particles at specific points on the surface of the celestial body and on the trajectory of the spacecraft, the observation data includes energy spectrum flux data.

[0013] As an improvement of the above method, for a plasma detection instrument, if it experiences solar wind, it has the ability to detect solar wind; if it experiences planetary magnetosphere, it has the ability to measure planetary magnetosphere plasma;

[0014] For energetic charged particle detection instruments, they have the ability to detect energetic charged particles, and the detection objects include the planetary radiation belts and solar cosmic rays that the detection target passes through.

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

[0016] When a celestial body moves in the solar wind, there is a period of time when there are no solar high-energy proton events and coronal mass ejection events; when a celestial body moves in the planetary magnetosphere, there is a period of time when there are no space environment disturbance events that may cause the overall increase or decrease of the plasma energy spectrum by more than 10% of its central velocity.

[0017] As an improvement of the above method, the charge potential at a specific point on the surface of a celestial body is calculated. When the celestial body moves in the solar wind, the charge potential V g The calculation formula is:

[0018] V g =E-E0 / Q

[0019] Wherein, E represents the energy value corresponding to the peak value of the solar wind center velocity; E0 represents the energy value corresponding to the peak value of the solar wind center velocity before the disturbance at the corresponding moment of the peak value of the solar wind center velocity; Q represents the charge number of the solar wind plasma;

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

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

[0022] Among them, E' represents the energy value corresponding to the peak value of the center velocity of the planetary magnetosphere plasma; E0' represents the energy value corresponding to the peak value of the center velocity of the planetary magnetosphere plasma before the disturbance at the corresponding moment of the peak value of the center velocity of the planetary magnetosphere plasma; Q' represents the charge number of the planetary magnetosphere plasma.

[0023] As an improvement of 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]

[0028] J B =Y BE (J E +Y BI J I )

[0029] When the Debye radius ≥ the characteristic size of the celestial body:

[0030] J E =J E0 (1+eU / E)

[0031] J I =J I0 (1-eU / E)

[0032] When the Debye radius < the characteristic size of the celestial body:

[0033] J E =J E0 (1+eU / E),U<0;J E =J E0 ,U≥0

[0034] J I =J I0 (1-eU / E),U>0;J I =J I0 ,U≤0

[0035] Among them, J V is the photocurrent; J I is the ion current density; J E is the electron current density; J B is the backscattered current density; J SEC is the secondary electron current density; e is the unit charge; J E0 is the incident electron current density with energy E; J I0 is the incident ion current density with energy E; U is the surface potential of the celestial body; J SECE is the secondary electron current density of the incident electron; Y SE is the secondary generation rate of the incident electrons; J SECI is the secondary electron current density of the incident proton; Y SI is the secondary production rate of incident protons; Y BE and Y BI are the reflection coefficients of ions and electrons reflected from the surface of the celestial body; δ m is the maximum secondary electron generation rate generated by the incident electron; Q E =2.28(Em / E) 1.35 ; E m is the incident electron energy that produces the maximum incidence rate; Q I =1 / E-0.1; Y1 is the generation rate of incident protons with energy 1keV; E m is the incident electron energy that produces the maximum incidence of incident protons.

[0036] As an improvement of the above method, the quantitative relationship between the peak observation data of the total directional flux of each energy spectrum of plasma and energetic charged particles measured by the upstream spacecraft and the specific point on the surface of the celestial body is expressed as a function F(Φ) of the angle Φ between the center of the field of view at the specific point vertical to the surface of the celestial body and the center of velocity of the incident plasma or energetic charged particles.

[0037] As an improvement of the above method, when the celestial body to be measured is the moon, the field of view Φ is the angle between the central flux direction of the charged particles and the line connecting each point on the lunar surface and the center of the moon; a period of quiet solar activity is selected to obtain data from multiple rotation cycles, average them point by point, and fit to obtain the quantitative relationship function F(Φ).

[0038] As an improvement on the above method, when the celestial body to be measured is not the moon, the quantitative relationship between the peak observation data of the total directional flux of each energy spectrum of plasma and energy charged particles measured respectively by the upstream spacecraft and the specific point on the surface of the celestial body is calculated using the quantitative relationship obtained by the moon, and the measured data of plasma and energy charged particles on the celestial body orbiter are used as the upstream observation data to achieve a rough estimation of the charging potential at different positions and times on the surface of the celestial body.

[0039] Compared with the prior art, the advantages of this application are:

[0040] Plasma and energetic charged particle detectors are widely used in the solar-terrestrial space, and this type of payload is usually the preferred payload for scientific exploration payloads carried by celestial orbiters and landers. This type of equipment can not only be used to obtain local plasma and energetic charged particle detection data, but the plasma observation equipment on the lander can also calculate the surface charging potential of the satellite or celestial body surface observation point during a calm space environment. However, it is difficult for this type of equipment to calculate the charging potential during a disturbance in the space environment.

[0041] The present invention utilizes this type of payload, which can not only solve the problem that there is no method for synchronously acquiring the surface charge potential at different positions on the surface of a celestial body at any time, but also realize the convenient acquisition of the surface charge potential at different positions on the surface of a celestial body, providing protection for the extraterrestrial survival of aerospace equipment and life, but also has high cost-effectiveness, avoiding the problem of waste of resources by laying a large number of potential detection payloads on the surface. The present invention has a wide range of application needs in the field of high-vacuum celestial body detection without intrinsic magnetic field such as the moon.

[0042] Through the method for obtaining the charging potential of different areas on the surface of a high-vacuum celestial body with no intrinsic magnetic field provided by the present invention, it is only necessary to launch a plasma and energy charged particle detector at a specific point near the surface of the celestial body once, and cooperate with the observation data of a large number of upstream spacecraft carrying plasma and energy charged particle detectors. It is possible to establish a surface charging potential model for a high-vacuum celestial body with no intrinsic magnetic field, which only uses the plasma and energy charged particle observation data of upstream spacecraft as input data. The model can be used to calculate and determine the surface charging potential of the celestial body at different times and different locations on the globe. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Shown is a flow chart of a method for obtaining the surface charge potential of a high-vacuum celestial body with no intrinsic magnetic field. DETAILED DESCRIPTION

[0044] The technical solution of the present application is described in detail below with reference to the accompanying drawings.

[0045] The present invention provides a method for obtaining the surface charge potential of a high-vacuum celestial body without intrinsic magnetic field, and the method comprises the following steps: placing a plasma and energy charged particle observation instrument at a specific point on the surface of a high-vacuum celestial body without intrinsic magnetic field and on a spacecraft operating in a plasma environment close to the upstream of the celestial body, obtaining observation data of plasma and energy charged particles at the specific point on the surface of the celestial body and on the trajectory of the spacecraft; calculating the charge potential of the specific point on the surface of the celestial body according to the disturbance of the plasma data in a specific period of time; calculating the charge potential of the specific point on the surface of the celestial body according to the observation data of plasma and energy charged particles at the specific point on the surface of the celestial body, ... The charging potential at a specific point on the surface of the celestial body can be used to establish a charging potential model for the specific point on the surface of the celestial body; the quantitative relationship between the peak observation data of the total directional flux of each energy spectrum of plasma and energetic charged particles measured by the upstream spacecraft and the specific point on the surface of the celestial body at different angles between the center of the field of view at the specific point on the surface of the celestial body and the velocity center of the incident plasma or energetic charged particles is obtained; the quantitative relationship is substituted into the charging potential model for the surface of the celestial body at a specific point, and a charging potential model for the surface of a celestial body with a high vacuum degree and no intrinsic magnetic field is established, which is used to calculate and determine the charging potential at different positions on the surface of the celestial body.

[0046] A method for obtaining the charging potential of different regions on the surface of a high vacuum celestial body without intrinsic magnetic field, the specific steps of the method are as follows:

[0047] Step 1: Deploy plasma and energetic charged particle observation instruments at specific points on the surface of a high-vacuum celestial body with no intrinsic magnetic field and on a spacecraft operating in the same plasma region upstream of the celestial body (for example, if it experiences solar wind, the upstream refers to the side of the celestial body in the orbit between the celestial body and the sun, close to the sun; if it is a planetary magnetosphere, the upstream refers to the side of the planet between the planet and the celestial body, close to the planet), and obtain observation data (energy spectrum flux data, etc.) on the plasma and energetic charged particles at specific points on the surface of the celestial body and on the trajectory of the spacecraft.

[0048] The specific points on the surface of a celestial body are one or more points in the area to be tested on the surface of the celestial body.

[0049] Among them, for plasma detection instruments, if they experience solar wind, they must have the ability to detect solar wind; if they experience planetary magnetosphere, they should have the ability to measure planetary magnetosphere plasma.

[0050] Energy charged particle detection instruments should have the ability to detect energy charged particles, mainly the ability to detect electrons with energies below MeV. The detection objects include the planetary radiation belts and solar cosmic rays that the detection target passes through.

[0051] For example, for the moon, the trajectory passes through the solar wind and the earth's magnetosphere, so the plasma observation deployed on the lunar surface should be able to obtain the flux spectra of the solar wind and the earth's magnetosphere; energetic charged particles should have the ability to detect solar high-energy particles based on the lunar environment; upstream plasma and energetic particle data can use synchronous observation data from relay satellites, orbiters, or other existing satellites in the solar-terrestrial space close to the moon. If the planned landing area is located in the high-latitude polar region of the moon, the plasma and energetic charged particle observation instruments can be deployed in this area without selecting other special locations.

[0052] Step 2: Calculate the charge potential at a specific point on the surface of the celestial body based on the disturbance of plasma data in a specific period of time;

[0053] A specific period refers to a period when a celestial body is moving in the solar wind and there are no solar high-energy proton events, coronal mass ejection events and other solar activity outbursts; when a celestial body is moving in the planetary magnetosphere, there are no magnetic storms and other space environment disturbance events that may cause the overall plasma energy spectrum to rise or fall by more than 10% of its central velocity. There is no specific data on whether the space environment is disturbed, and it is defined based on whether a certain type of event occurs. These events have their own definitions.

[0054] Using the observed time-continuous plasma energy spectrum data, for solar wind plasma, the moment when the relatively slowly changing solar wind center velocity (the velocity corresponding to the flux peak of the energy spectrum data at each sampling moment) suddenly rises / falls when the solar activity is calm should be selected as the moment when the charging event occurs. At this time, the difference between the energy value E corresponding to the peak of the solar wind center velocity and the energy value E0 corresponding to the peak of the solar wind center velocity before the disturbance at this moment divided by the charge number Q of the solar wind plasma is the charging potential V. g .

[0055] V g =E-E0 / Q

[0056] When passing through the planetary magnetosphere, the charging potential formula is the same as the above formula. The difference is that E represents the energy value corresponding to the peak value of the center velocity of the planetary magnetosphere plasma; E0 represents the energy value corresponding to the peak value of the center velocity of the planetary magnetosphere plasma before the disturbance at that moment; Q represents the charge number of the planetary magnetosphere plasma.

[0057] Step 3: Combine the observation data of plasma and energetic charged particles at specific points on the surface of the celestial body and the observation value of the charging potential at specific points on the surface of the celestial body, and establish the surface charging potential model of specific points on the celestial body according to the following current balance equation and parameter calculation formula. The formula is as follows:

[0058] According to the plasma Debye radius and the characteristic size of the celestial body, determine which of the following formulas to use. If the Debye radius ≥ the characteristic size of the celestial body, use the following formula:

[0059] J V +J I +J E +J B +J SEC =0 (1)

[0060] J E =J E0 (1+eU / E) (2)

[0061] J I =J I0 (1-eU / E) (3)

[0062] J SECE =Y SE J E (4)

[0063] J SECI =Y SI J I (5)

[0064]

[0065] J B =Y BE (J E +Y BI J I ) (8)

[0066] Among them J V is the photocurrent, J I is the ion current density, J E is the electron current density, J B is the backscattered current density, J SEC is the secondary electron current density, e is the unit charge, J 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, J SECE is the secondary electron current density of the incident electrons, Y SE is the secondary generation rate of the incident electrons, J SECI is the secondary electron current density of the incident proton, Y SI is the secondary production rate of incident protons, Y BE and Y BI are the reflection coefficients of ions and electrons reflected from the surface of the celestial body, respectively. In formula (6), δ m The maximum secondary electron generation rate generated by the incident electron, Q E =2.28(Em / E) 1.35 , E mis the incident electron energy that produces the maximum incidence rate, (7) where Q I =1 / E-0.1, Y1 is the generation rate of incident protons with energy 1keV, E m is the incident electron energy that produces the maximum incidence of incident protons.

[0067] If the Debye radius is less than the characteristic size of the celestial body, then equations (2) and (3) are replaced by the following formula:

[0068] J E =J E0 (1+eU / E),U<0

[0069] J E =J E0 ,U≥0 (2)

[0070] J I =J I0 (1-eU / E),U>0

[0071] J I =J I0 ,U≤0 (3)

[0072] For the moon, the formula that the Debye radius is much larger than the characteristic size of the celestial body can be used, and the average value of the lunar photocurrent can be selected as 50 microamperes per square meter; the average value of the reflection coefficient of the solar wind plasma current can be selected as 20%.

[0073] Step 4: Use the fitting method to obtain the quantitative relationship between the total directional flux peak values ​​of plasma and energetic charged particles measured by the upstream spacecraft and the specific points on the surface of the celestial body. The quantitative relationship can be expressed as a function F(Φ) of the angle Φ between the center of the field of view at the specific point on the surface of the celestial body and the velocity center of the incident plasma or energetic charged particles. The ion and electron currents at the specific point on the surface of the celestial body can be calculated by F(Φ). The method for selecting the peak value of the total directional flux of the energy spectrum is: for plasma, the maximum value of the flux data of each energy spectrum in all directions of the observation data is selected; for energetic charged particles, the maximum value of the omnidirectional flux data in different energy bands is selected.

[0074] The method for selecting the peak value of the total directional flux of the energy spectrum is as follows:

[0075] For plasma, the peak value of the total directional flux of the energy spectrum is the maximum value of the energy spectrum flux data in all directions of the selected observation data:

[0076] F max =max(Σ E Σ ang F Ef_ang )

[0077] Among them, F Ef_angIt is the flux data at different energy bands and angles;

[0078] For energetic charged particles, the peak value of the total directional flux of the energy spectrum is the maximum value of the omnidirectional flux data in different energy bands:

[0079] F E_max =max(Σ ang F Ef_ang )

[0080] For the moon, we can choose to obtain data from multiple rotation cycles during a period of quiet solar activity, average them point by point, and fit them to obtain the above-mentioned quantitative relationship function F(Φ). Based on F(Φ), we can calculate the particle flux received by different regions of the celestial body.

[0081] Step 5: Substitute the quantitative relationship F(Φ) into the surface charge potential model of a specific point on a celestial body, and establish a surface charge potential model for a high-vacuum celestial body with no intrinsic magnetic field, so as to achieve the goal of calculating the charge potential of each point on the surface of the celestial body at any time based on the observation of plasma and energetic charged particles by upstream spacecraft.

[0082] For the moon, assuming it is round, the field of view Φ can be regarded as the angle between the central flux direction of the charged particles and the line connecting each point on the lunar surface and the center of the moon.

[0083] At present, there are a lot of observation data on the moon, and this method can be used to establish a surface charging model. However, other similar celestial bodies have not yet been landed for observation. This method can be expanded to roughly estimate the charging potential of each point on the surface of a high-vacuum celestial body with no intrinsic magnetic field at any time by adding assumptions. The method is: assuming that the quantitative relationship between the surface of the celestial body and the upstream observation data can be directly used as the quantitative relationship calculated by the moon, the measured data of plasma and energetic charged particles on the celestial body orbiter are used as upstream observation data, which can achieve a rough estimate of the charging potential at different positions and times on the celestial body surface.

[0084] The present invention provides a method for obtaining the charging potential of the surface of a high-vacuum celestial body without intrinsic magnetic field. The method comprises the following steps: arranging plasma and energetic charged particle observation instruments at specific points on the surface of a high-vacuum celestial body without intrinsic magnetic field and on a spacecraft operating in a plasma environment close to the upstream of the celestial body, obtaining observation data of plasma and energetic charged particles at the specific points on the surface of the celestial body and on the trajectory of the spacecraft during the same period; and obtaining the quantitative relationship between the observation data of the total directional flux peak values ​​of each energy spectrum of the upstream spacecraft and the specific points on the surface of the celestial body during a period when the space environment is relatively calm by a fitting method. The quantitative relationship varies with the angle between the center of the field of view of the specific point on the surface of the celestial body and the center of the velocity of the incident plasma or energetic charged particles. The quantitative relationship can be used to calculate the amount of energy received by different regions of the celestial body. particle flux; then, the charging potential at a specific point on the celestial body's surface is calculated based on the disturbance of the plasma data when the space environment is relatively calm; a charging potential model for a specific point on the celestial body's surface is established by combining the observational data of plasma and energetic charged particles at a specific point on the celestial body's surface, the charging potential at a specific point on the celestial body's surface, and theoretical formulas related to surface charging. This model can use the flux changes of plasma and energetic particles injected as input parameters to calculate the charging potential at that point; replacing the input parameters of the celestial body surface charging potential model for a specific point with the quantitative relationship of calculating the particle flux in different regions using the upstream data mentioned above can re-establish a high-vacuum celestial body surface charging potential model with no intrinsic magnetic field that is only related to the upstream plasma and energetic charged particle data, thereby realizing the use of the model to calculate the charging potential at different positions on the celestial body's surface. This method can not only realize the acquisition of the charging potential of each point on the surface of such celestial bodies at any time, but also is economically feasible. It only requires the deployment of plasma and energetic charged particle observation instruments at a specific point on the surface of the celestial body to obtain the quantitative relationship between the total flux peak of plasma and energetic charged particles between the upstream solar wind and the observation point, as well as the charging model of the specific point. This quantitative relationship is substituted into this model to form a new charging potential model for the surface of the celestial body. In this way, the plasma and energetic charged particle observation data of other satellites upstream can be used to obtain the charging potential values ​​of various regions on the surface of the celestial body.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application is described in detail with reference to the embodiments, a person skilled in the art should understand that any modification or equivalent replacement of the technical solution of the present application does not depart from the spirit and scope of the technical solution of the present application and should be included in the scope of the claims of the present application.

Claims

1. A method for obtaining the surface charge potential of a high vacuum celestial body without intrinsic magnetic field, comprising: Step 1: Plasma detection instruments and energetic charged particle detection instruments are deployed at specific points on the surface of a high-vacuum celestial body with no intrinsic magnetic field and on a spacecraft operating in the same plasma region upstream of the celestial body to obtain observation data of plasma and energetic charged particles at specific points on the surface of the celestial body and on the trajectory of the spacecraft; Step 2: Calculate the charge potential at a specific point on the surface of the celestial body based on the disturbance of plasma data in a specific period of time; Step 3: Combine the observation data of plasma and energetic charged particles at specific points on the surface of the celestial body with the observation value of the charging potential at specific points on the surface of the celestial body, and establish a surface charging potential model for specific points on the celestial body according to the current balance equation and parameter calculation formula; Step 4: Use the fitting method to obtain the quantitative relationship between the peak values ​​of the total directional flux of plasma and energetic charged particles in each energy spectrum measured by the upstream spacecraft and the specific points on the surface of the celestial body; Step 5: Substitute the quantitative relationship into the surface charging potential model of a specific point on the celestial body, establish a surface charging potential model for a high-vacuum celestial body with no intrinsic magnetic field, and calculate the charging potential of the surface area to be measured at any time based on the observation of plasma and energetic charged particles by upstream spacecraft.

2. The method for obtaining the surface charge potential of a high vacuum celestial body without intrinsic magnetic field according to claim 1, characterized in that: When experiencing the solar wind, the upstream of the celestial body refers to the side of the celestial body close 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 of the celestial body between the planet and the celestial body close to the planet.

3. The method for obtaining the surface charge potential of a high vacuum celestial body without intrinsic magnetic field according to claim 1, characterized in that: In the acquisition of observation data of plasma and energetic charged particles at specific points on the surface of a celestial body and on the trajectory of the spacecraft, the observation data includes energy spectrum flux data.

4. The method for obtaining the surface charge potential of a high vacuum celestial body without intrinsic magnetic field according to claim 1, characterized in that: For plasma detection instruments, if they experience solar wind, they have the ability to detect solar wind; if they experience planetary magnetosphere, they have the ability to measure the plasma in the planetary magnetosphere; For energetic charged particle detection instruments, they have the ability to detect energetic charged particles, and the detection objects include the planetary radiation belts and solar cosmic rays that the detection target passes through.

5. The method for obtaining the surface charge potential of a high vacuum celestial body without intrinsic magnetic field according to claim 1, characterized in that: The specific time period includes: When a celestial body moves in the solar wind, there is a period of time when there are no solar high-energy proton events and coronal mass ejection events; when a celestial body moves in the planetary magnetosphere, there is a period of time when there are no space environment disturbance events that may cause the overall increase or decrease of the plasma energy spectrum by more than 10% of its central velocity.

6. The method for obtaining the surface charge potential of a high vacuum celestial body without intrinsic magnetic field according to claim 1, characterized in that: The charge potential at a specific point on the surface of a celestial body is calculated. When the celestial body moves in the solar wind, the charge potential V g The calculation formula is: V g =E-E0 / Q Wherein, E represents the energy value corresponding to the peak value of the solar wind center velocity; E0 represents the energy value corresponding to the peak value of the solar wind center velocity before the disturbance at the corresponding moment of the peak value of the solar wind center velocity; Q represents the charge number of the solar wind plasma; When a celestial body moves in the planetary magnetosphere, the charge potential V g The calculation formula is: V g =E'-E0' / Q' Among them, E' represents the energy value corresponding to the peak value of the center velocity of the planetary magnetosphere plasma; E0' represents the energy value corresponding to the peak value of the center velocity of the planetary magnetosphere plasma before the disturbance at the corresponding moment of the peak value of the center velocity of the planetary magnetosphere plasma; Q' represents the charge number of the planetary magnetosphere plasma.

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

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

9. The method for obtaining the surface charge potential of a high vacuum celestial body without 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 central flux direction of the charged particles and the line connecting each point on the lunar surface and the center of the moon; a period of solar activity calm is selected to obtain data from multiple rotation cycles, average them point by point, and fit to obtain the quantitative relationship function F(Φ).

10. The method for obtaining the surface charge potential of a high vacuum celestial body without intrinsic magnetic field according to claim 1, characterized in that: When the celestial body to be measured is not the moon, the quantitative relationship between the peak observation data of the total directional flux of each energy spectrum of plasma and energy charged particles measured respectively by the upstream spacecraft and the specific point on the surface of the celestial body is calculated using the quantitative relationship obtained by the moon, and the measured data of plasma and energy charged particles on the celestial body orbiter 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.

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