Method for extracting collision frequency of F region of ionized layer based on incoherent scatter radar

Abstract

The invention belongs to the field of signal and information processing, particularly relates to a method for extracting the collision frequency of an F region of an ionized layer based on an incoherent scatter radar, and aims to solve the problem that the 24-hour change of the collision frequency of the F region of the ionized layer cannot be obtained. The method comprises the following steps: acquiring an ionosphere parameter of an ionosphere F region based on an incoherent scatter radar; acquiring an ion vector speed according to the ion line-of-sight speeds in the plurality of line-of-sight directions; under the condition that the diffusion velocity of ions in the ionized layer is 0, the diffusion velocity zero value height is determined based on the electron density, the electron temperature, the ion temperature and the ion mass; determining a target diffusion velocity of the target height based on the warp wind at the diffusion velocity zero height, the ion vector velocity and the magnetic dip angle; and determining the collision frequency of the ionosphere F region based on the target diffusion velocity. According to the invention, 24-hour continuous measurement of the collision frequency of the F region of the ionized layer is realized.

Description

Background Art

[0002] The ionosphere is a key layer in the solar-terrestrial space environment that is most closely related to human activities and has important impacts on radio communication, satellite navigation and positioning, manned spaceflight, etc.

[0003] Observations show that the electron density in the ionosphere has a layered structure in the vertical direction. In the altitude range of about 60 - 1000 kilometers from the Earth's surface, there are mainly three layers: the D layer, the E layer, and the F layer. The D layer is the bottom of the ionosphere, consisting of a layer of the atmosphere with a relatively low degree of ionization, located in the region of about 60 - 90 kilometers. The E layer is in the region of about 90 - 140 kilometers, and its position is relatively stable. Above the E layer up to hundreds or even thousands of kilometers is collectively called the F layer, which is the main region of the ionosphere.

[0004] Due to the absorption of solar radiation, the oxygen ions (O + +) ionized from oxygen atoms (O) in the ionosphere are the main components of the F region of the Earth's ionosphere. The interaction between O + + and O, especially through collisions, controls the structure and dynamic processes of the upper atmosphere of the Earth (see reference: Salah, J. E. (1993). Interim standard for the ion-neutral atomic oxygen collision frequency. Geophysical Research Letters, 20(15), 1543 - 1546. https: / / doi.org / 10.1029 / 93GL01699), including their velocities, temperatures, and densities. Therefore, the O + +-O collision frequency is a fundamental parameter describing the interaction between ions and neutral components in the ionosphere-thermosphere system.

[0005] However, there is currently no sufficient method to directly measure the O + +-O collision frequency under the thermal conditions of the upper atmosphere. Through extrapolation of laboratory data or quantum mechanical calculations, many scholars have carried out O +Calculation of the O+-O collision frequency (for references, see Pesnell, W. D., Omidvar, K., & Hoegy, W. R. (1993). Momentum transfer collision frequency of O+-O. Geophysical Research Letters, 20(13), 1343–1346. https: / / doi.org / 10.1029 / 93GL01597; Stallcop, J. R., Partridge, H., & Levin, E. (1991). Resonance charge transfer, transport cross sections, and collision integrals for N+(3P)-N(4S) and O+(4S)-O(3P) interactions. The Journal of chemical physics, 95(9), 6429–6439. https: / / doi.org / 10.1063 / 1.461563; Stebbings, R. F., Smith, A. C. H., & Ehrhard, H. (1964). Charge transfer between oxygen atoms and O+ and H+ ions. Journal of Geophysical Research, 69(11), 2349–2355. https: / / doi.org / 10.1029 / JZ069i011p02349). So far, only Stebbings et al. (1964) have directly measured the cross section of the O+-O collision frequency, but it has to be extrapolated from energies above 40 eV to below 1 eV. For many years, O + +-O collision frequency cross section, but it has to be extrapolated from energies above 40 eV to below 1 eV. For many years, O +The expression of the -O collision cross-section has been theoretically calculated and analyzed. The most commonly used formula is Banks (for references: Banks, P. (1966). Collision frequencies and energy transferions. Planetary and Space Science, 14(11), 1105–1122; Salah, J. E. (1993). Interim standard for the ion-neutral atomic oxygen collision frequency. Geophysical Research Letters, 20(15), 1543-1546. https: / / doi.org / 10.1029 / 93GL01699; Schunk, R. W., & Walker, J. C. G. (1973). Theoretical ion densities in the lower ionosphere. Planetary and Space Science, 21(11), 1875–1896. https: / / doi.org / 10.1016 / 0032-0633(73)90118-9). In addition to the above collision cross-section, when calculating the collision frequency, the density of oxygen atoms is also required, which is usually derived from empirical models.

[0006] Among all ionospheric sounding means, the Incoherent Scatter Radar (ISR) is by far the most powerful sounding means, which has many advantages such as strong detection function, multiple parameters (multiple fields and particle components), high accuracy, good resolution, and large height range coverage. The high-power phased array incoherent scatter radar developed and built in Sanya in the low-latitude region of the ionosphere has new advantages in technology such as continuous observation, full-airspace coverage, and rapid local space scanning.

[0007] Incoherent scatter radar observations provide several ways to verify the collision cross sections determined from laboratory data or quantum mechanical calculations. Whether it is the energy balance (EB) method (for references, see Carlson, H. C., & Harper, R. M. (1977). An experimental estimate of the O+-O resonant charge transfer cross section, collision frequency, and energy transfer rate. Journal of Geophysical Research, 82(7), 1144–1148. https: / / doi.org / 10.1029 / JA082i007p01144; Burnside, R. G., Sulzer, M. P., & Walker, J. C. G. (1988). Determination of thermospheric temperatures and neutral densities at Arecibo from the ion energy balance. Journal of Geophysical Research, 93(A8), 8642–8650. https: / / doi.org / 10.1029 / JA093iA 08p08642; Nicolls, M. J., Aponte, N., González, S. A., Sulzer, M. P., & Oliver, W. L. (2006). Daytime F region ion energy balance at Arecibo for moderate to high solar flux conditions. Journal of Geophysical Research, 111, A10307. https: / / doi.org / 10.1029 / 2006JA011664; Oliver, W. L., & Glotfelty, K. (1996). O+-O collision cross section and long-term F region O density variations deduced from the ionospheric energy budget.Journal of Geophysical Research, 101(A10), 21,769–21,784. https: / / doi.org / 10.1029 / 96JA01585; Winser, K. J., Farmer, A. D., Rees, D., & Aruliah, A. (1988). Ion-neutral dynamics in the high latitude ionosphere: First results from the INDI experiment. Journal of Atmospheric and Terrestrial Physics, 50(4), 369–377. https: / / doi.org / 10.1016 / 0021-9169(88)90021-9) or the momentum balance (MB) method (for references, see: Buonsanto, M. J., Tung, Y. K., & Sipler, D. P. (1992). Neutral atomic oxygen density from nighttime radar and optical wind measurements at Millstone Hill. Journal of Geophysical Research, 97(A6), 8673–8679. https: / / doi.org / 10.1029 / 92JA00435; Davis, C. J., Farmer, A. D., & Aruliah, A. (1995). An optimised method for calculating the O+-O collision parameter from aeronomical measurements. Annales Geophysicae, 13(5), 541–550. https: / / doi.org / 10.1007 / s00585-995-0541-x; Reddy, C. A., Hoegy, W. R., Pesnell, W. D., Mayr, H. G., & Hines, C. O. (1994). Accuracy of O+-O collision cross-section deduced from ionosphere-thermosphere observations.Geophysical Research Letters, 21(22), 2429–2432. https: / / doi.org / 10.1029 / 94GL02494; Sipler, D. P., Hagan, M. E., Zipf, M. E., & Biondi, M. A. (1991). Combined optical and radar wind measurements in the F region over Millstone Hill. Journal of Geophysical Research, 96(A12), 21,255–21,262. https: / / doi.org / 10.1029 / 91JA02371; Vickers, H., Kosch, M. J., Sutton, E., Ogawa, Y., & La Hoz, C. (2013). Thermospheric atomic oxygen density estimates using the EISCAT Svalbard Radar. Journal of Geophysical Research: Space Physics, 118, 1319–1330. https: / / doi.org / 10.1002 / jgra.50169; Wu, Q., Wang, W., Roble, R. G., Hággstróm, I., & Strømme, A. (2012). First daytime thermospheric wind observation from a balloon-borne Fabry-Perot interferometer over Kiruna (68N). Geophysical Research Letters, 39, L14104. https: / / doi.org / 10.The 1029 / 2012GL052533 can be used to estimate the collision frequency, mainly by correcting the theoretical collision cross-section, and then obtaining an accurate collision frequency. The EB method mainly measures and calculates the density of neutral atomic oxygen through an incoherent scatter radar (ISR), and obtains the collision frequency coefficient by comparing the density of neutral atomic oxygen obtained by the ISR with that obtained by the empirical model, and then obtains an accurate collision frequency. For the MB method, the meridional wind measured by the ISR is calibrated with the meridional wind measured by the nearby Fabry-Perot interferometer (FPI), and then the collision frequency coefficient is determined, and then an accurate collision frequency is obtained.

[0008] However, the observational data of most of the above studies are very limited, which restricts our understanding of the collision frequency coefficient. On the one hand, the MB method using FPI data is only available at night, while the EB method is mainly applicable during the day. Generally speaking, the EB and MB methods obtain collision frequency coefficients at different local times, and the collision frequencies obtained by these two methods cannot cover the complete 24 hours. On the other hand, both of the above two methods provide an average value. However, this average value may only be a rough approximation, and its collision frequency varies within 24 hours. There is currently no method to obtain the results of the collision frequency varying with 24 hours. Summary of the Invention

[0009] To solve the above problems in the prior art, that is, the problem of being unable to obtain the variation of the collision frequency in the F region of the ionosphere with 24 hours, in the first aspect of the present application, a method for extracting the collision frequency in the F region of the ionosphere based on an incoherent scatter radar is proposed, including: Step S10, obtaining ionospheric parameters in the F region of the ionosphere based on an incoherent scatter radar, where the ionospheric parameters include electron density, electron temperature, ion temperature, and ion line-of-sight velocity; Step S20, obtaining the ion vector velocity according to the ion line-of-sight velocities in multiple line-of-sight directions; Step S30, when the diffusion velocity of ions in the ionosphere is 0, determining the zero diffusion velocity height based on the electron density, electron temperature, ion temperature, and ion mass; Step S40, determining the target diffusion velocity at the target height based on the meridional wind at the zero diffusion velocity height, the ion vector velocity, and the magnetic dip angle, where the target height is the height above the zero diffusion velocity height; Step S50, determining the collision frequency in the F region of the ionosphere based on the target diffusion velocity.

[0010] As a preferred implementation manner, determining the zero diffusion velocity height includes: Set the diffusion velocity in the diffusion formula to zero, and determine the zero-height of the diffusion velocity according to the electron density, the electron temperature, the ion temperature, and the ion mass in the diffusion formula; wherein, the diffusion formula is:

[0011] wherein, represents the diffusion velocity, k represents the Boltzmann constant, represents the ion temperature, represents the electron temperature, represents the sine value of the magnetic dip angle I of, represents the ion mass, represents the collision frequency, represents the electron density, represents the partial derivative symbol, h represents height, and g represents the acceleration due to gravity.

[0012] As a preferred embodiment, determining the target diffusion velocity of the target height includes:

[0013] wherein, represents the target diffusion velocity, represents the velocity along the magnetic field line direction, represents the meridional wind at the zero-height of the diffusion velocity, cos I represents the cosine value of the magnetic dip angle, wherein, the velocity along the magnetic field line direction is one of the ion vector velocities.

[0014] As a preferred embodiment, the meridional wind at the zero-height of the diffusion velocity includes:

[0015] wherein, represents the velocity along the magnetic field line direction at the zero-height of the diffusion velocity.

[0016] As a preferred embodiment, determining the collision frequency of the F region of the ionosphere based on the target diffusion velocity includes:

[0017] wherein, represents the collision frequency, k represents the Boltzmann constant, represents the ion temperature, represents the electron temperature, represents the magnetic dip angle I of the sine value, represents the ion mass, represents the target diffusion velocity, represents the electron density, represents the partial derivative symbol, represents the target height, and g represents the acceleration due to gravity.

[0018] As a preferred implementation manner, based on the incoherent scatter radar to obtain the ionospheric parameters of the F region of the ionosphere, including: Obtain the scattered signal generated by the incoherent scatter radar emitting electromagnetic waves to the ionosphere; At different heights, fit the theoretical power spectrum and the measured power spectrum of the scattered signal; When the fitting error between the theoretical power spectrum and the measured power spectrum is minimized, obtain the ionospheric parameters.

[0019] As a preferred implementation manner, according to the ion line-of-sight velocities in multiple line-of-sight directions, obtain the ion vector velocity, including: According to the relationship between the ion line-of-sight velocity and the vector velocity in the geomagnetic coordinate system, combined with the ion line-of-sight velocities in different directions, perform least squares fitting to obtain the ion vector velocity.

[0020] In a second aspect of the present application, a system for extracting the collision frequency of the F region of the ionosphere based on an incoherent scatter radar is proposed, including: An ionospheric parameter acquisition module, configured to obtain the ionospheric parameters of the F region of the ionosphere based on the incoherent scatter radar, where the ionospheric parameters include electron density, electron temperature, ion temperature, and ion line-of-sight velocity; An ion vector velocity acquisition module, configured to obtain the ion vector velocity according to the ion line-of-sight velocities in multiple line-of-sight directions; A diffusion velocity zero-value height determination module, configured to, when the diffusion velocity of ions in the ionosphere is 0, determine the diffusion velocity zero-value height based on the electron density, electron temperature, ion temperature, and ion mass; A target diffusion velocity determination module, configured to determine the target diffusion velocity at the target height based on the meridional wind at the diffusion velocity zero-value height, the ion vector velocity, and the magnetic dip angle, where the target height is a height above the diffusion velocity zero-value height; A collision frequency determination module, configured to determine the collision frequency of the F region of the ionosphere based on the target diffusion velocity.

[0021] In a third aspect of the present application, an electronic device is proposed, including: At least one processor; and A memory communicatively connected to at least one of the processors; where, The memory stores instructions executable by the processor, and the instructions are used to be executed by the processor to implement the method for extracting the collision frequency of the F region of the ionosphere based on incoherent scatter radar as described above.

[0022] In the fourth aspect of the present application, a computer-readable storage medium is proposed. The computer-readable storage medium stores computer instructions, and the computer instructions are used to be executed by the computer to implement the method for extracting the collision frequency of the F region of the ionosphere based on incoherent scatter radar as described above.

[0023] Advantages of the present application: The present application realizes continuous 24-hour measurement of the collision frequency of the F region of the ionosphere.

[0024] (1) The present application uses the Sanya incoherent scatter radar to obtain the ionospheric parameters of the F region of the ionosphere, and further calculates the target diffusion velocity at the target height through the zero diffusion velocity height, so as to realize the measurement of the collision frequency. Since all ionospheric parameters can be continuously sampled for 24 hours, the method of the present application can obtain accurate collision frequency results and changes for 24 hours, and does not depend on other observation means.

[0025] (2) The coupling between the thermosphere and the ionosphere is mainly through the collision interaction between particles. The collision frequency is a very important parameter and is also a very difficult parameter to measure. In this paper, the Sanya incoherent scatter radar is used to measure the accurate collision frequency, and the interaction and coupling mechanism between the thermosphere and the ionosphere can be further analyzed.

[0026] (3) With more data collected by the Sanya incoherent scatter radar in the future, it will be possible to analyze the collision frequency under different seasons and different solar activities. According to the measurement results of the collision frequency, we can further refine the collision frequency in the existing theoretical model, so as to possibly optimize the existing theoretical model and further improve the accuracy of the theoretical model. Description of the Drawings

[0027] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects, and advantages of the present application will become more obvious: Figure 1 is a flowchart of a method for extracting the collision frequency of the F region of the ionosphere based on incoherent scatter radar according to the first embodiment of the present application; Figure 2 is a time series diagram of the wind speed of the meridional wind corresponding to the zero diffusion velocity height provided by the first embodiment of the present application; Figure 3 is a time series diagram of the diffusion velocity at a target height provided by the first embodiment of the present application; Figure 4It is a time series diagram of the collision frequency coefficient within a target altitude of 10 km provided by the first embodiment of the present application; Figure 5 It is a comparison diagram of the collision frequency coefficient provided by the first embodiment of the present application; Figure 6 It is a system block diagram of a system for extracting the collision frequency of the F region of the ionosphere based on an incoherent scatter radar provided by the second embodiment of the present application; Figure 7 It is a schematic structural diagram of a computer system of a server for implementing the method, system, and device embodiments of the present application. Detailed implementation manners

[0028] The present application will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related invention and do not limit the invention. Additionally, it should be noted that for the sake of description, only parts related to the relevant invention are shown in the drawings.

[0029] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and embodiments.

[0030] The coupling of the ionosphere-thermosphere system is largely controlled by the collisions between ions and neutral particles. In the ionosphere-thermosphere system above an altitude of 200 km, O and O + are the main components. Therefore, the collision frequency of O + -O plays a crucial role in the momentum and energy transfer between the thermosphere and the ionosphere. For decades, researchers have mainly studied the O + -O collision frequency by using the energy balance and momentum balance methods and the observational data of incoherent scatter radars. However, these two methods are respectively limited to daytime and nighttime, and the energy balance method needs to rely on the results of models, and the momentum balance method needs to rely on FPI data. To solve this limitation, the present application provides a method for extracting the collision frequency of the F region of the ionosphere based on an incoherent scatter radar. This method uses the newly built Sanya incoherent scatter radar to calculate the collision frequency of the F region of the ionosphere, can obtain the 24-hour collision frequency, and does not need to rely on other observational data.

[0031] To more clearly illustrate the method of the present application for extracting the collision frequency of the F region of the ionosphere based on an incoherent scatter radar, the following combines Figure 1 to detail each step in the embodiments of the present application.

[0032] The method for extracting the collision frequency of the F region of the ionosphere based on an incoherent scatter radar according to the first embodiment of the present application includes steps S10 - S50, and each step is described in detail as follows: Step S10: Obtain the ionospheric parameters of the F region of the ionosphere based on an incoherent scatter radar, where the ionospheric parameters include electron density, electron temperature, ion temperature, and ion line-of-sight velocity.

[0033] It should be noted that when electromagnetic waves of a certain frequency are incident on the ionosphere, Thomson scattering will occur, and the scattered signal contains information such as the temperature, density, and drift velocity of the plasma.

[0034] Optionally, the incoherent scatter radar can generate a scattered signal by emitting electromagnetic waves to the ionosphere, and by receiving and processing the scattered signal, various parameters of the ionosphere can be measured.

[0035] In the embodiment of the present application, obtain the scattered signal generated by the incoherent scatter radar emitting electromagnetic waves to the ionosphere; at different altitudes, fit the theoretical power spectrum and the measured power spectrum of the scattered signal; when the fitting error between the theoretical power spectrum and the measured power spectrum is the smallest, obtain the ionospheric parameters.

[0036] Among them, at any altitude in the F region of the ionosphere, the theoretical power spectrum and the measured power spectrum of the scattered signal are fitted by least squares fitting, and the fitted electron density, electron temperature, ion temperature, and ion line-of-sight velocity are output as the ionospheric parameters at this arbitrary altitude.

[0037] Step S20: Obtain the ion vector velocity according to the ion line-of-sight velocities in multiple line-of-sight directions.

[0038] It should be noted that when obtaining the ion vector velocity, it is necessary to assume that the velocity field is spatially uniform, that is, assume that the vector velocity is unchanged within a certain spatial range, and the accurate ion vector velocity can be obtained through the ion line-of-sight velocities in three directions.

[0039] Optionally, according to the relationship between the ion line-of-sight velocity and the ion vector velocity in the geomagnetic coordinate system, combined with the ion line-of-sight velocities in different directions, least squares fitting is performed to obtain the ion vector velocity.

[0040] In the embodiment of the present application, according to the fast beam switching ability of the Sanya incoherent scatter radar, more beams can be used to perform least squares fitting within a certain spatial range, and then the ion vector velocity can be obtained.

[0041] In this embodiment, the process of obtaining the ion vector velocity is prior art, and reference can be made to the specific implementation of the patent: CN202310627691.7, which will not be elaborated here.

[0042] Step S30, when the diffusion velocity of ions in the ionosphere is 0, determine the zero diffusion velocity altitude based on the electron density, electron temperature, ion temperature, and ion mass.

[0043] Optionally, the diffusion velocity of ions in the F region of the ionosphere can be determined according to the diffusion velocity formula (for reference: Chen, G. M., Xu, J., Wang, W., Lei, J., & Zhang, S. R. (2014). The responses of ionospheric topside diffusive fluxes to two geomagnetic storms in October 2002. Journal of Geophysical Research: Space Physics, 119(8), 6806–6820. https: / / doi.org / 10.1002 / 2014ja020013). The diffusion formula is as follows:

[0044] where, represents the diffusion velocity, k represents the Boltzmann constant, represents the ion temperature, represents the electron temperature, represents the sine value of the magnetic dip angle I of, represents the ion mass, represents the collision frequency, represents the electron density, represents the partial derivative symbol, h represents altitude, and g represents the acceleration due to gravity.

[0045] Among them, the main component of ions in the F region of the ionosphere is oxygen ions. Therefore, the ion mass in the embodiments of this application refers to the oxygen ion mass, which is 16×amu, and the atomic mass amu = 1.6605402×10 -27 kg.

[0046] It should be noted that the ionosphere is a plasma layer, which is affected by electromagnetic forces in addition to gravity and collision effects. The collision frequency in the above diffusion formula is an unknown quantity, so the accurate diffusion velocity cannot be directly obtained.

[0047] Optionally, in order to eliminate the influence of the collision frequency, the diffusion velocity in the diffusion formula is set to zero, and the height of the zero diffusion velocity value is determined according to the electron density, electron temperature, ion temperature, and ion mass in the diffusion formula. That is, it is necessary to make the result within the brackets in the diffusion formula equal to 0, and the height of the zero diffusion velocity value can be calculated based on the ionospheric parameters obtained by the incoherent scatter radar.

[0048] Step S40: Determine the target diffusion velocity at the target height based on the meridional wind, ion vector velocity, and magnetic dip angle at the height of the zero diffusion velocity value, where the target height is the height above the height of the zero diffusion velocity value.

[0049] Optionally, when the diffusion velocity approaches 0, the meridional wind mainly depends on the velocity along the magnetic field line direction and the magnetic dip angle.

[0050] As an example, the meridional wind at the height of the zero diffusion velocity value can be determined by the following formula:

[0051] where represents the meridional wind at the height of the zero diffusion velocity value, cos I represents the cosine value of the magnetic dip angle, represents the velocity along the magnetic field line direction at the height of the zero diffusion velocity value.

[0052] It should be noted that the velocity along the magnetic field line direction is one of the ion vector velocities.

[0053] According to research (see references: Rishbeth, H., & Garriott, O. K. (1969), Introduction to Ionospheric Physics, Academic Press, New York.; Hedin, A. E., Spencer, N. W., Biondi, M. A., et al. (1991). Revised Global Model of Thermosphere Winds using satellite and Ground-based observations. Journal of Geophysical Research Atmospheres, 1991, 96(A5). https: / / doi.org / 10.102 9 / 91JA00251), the height gradient of the meridional wind in the high-altitude region (i.e., above the F layer of the ionosphere) can be neglected (see reference: Lei, J., Wang, W., Burns, A. G., Solomon, S. C., Richmond, A. D., Wiltberger, M., Goncharenko, L. P., Coster, A., & Reinisch, B. W. (2008). Observations and simulations of the ionospheric and thermospheric response to the December 2006 geomagnetic storm: Initial phase. Journal of Geophysical Research, 113, A01314. https: / / doi.org / 10.1029 / 2007JA012807.). The height where the diffusion velocity is 0 is usually always higher than the ionospheric peak height. Therefore, above the height where the diffusion velocity is 0, the meridional wind hardly changes. That is to say, the meridional wind at the height where the diffusion velocity is 0 can be used to represent the meridional wind at heights above where the diffusion velocity is 0 (i.e., the target height).

[0054] Furthermore, the target diffusion velocity at the target height can be obtained according to the following formula:

[0055] Wherein, represents the target diffusion velocity, represents the velocity along the magnetic field line direction.

[0056] In the embodiment of the present application, the meridional wind at the zero value height of the diffusion speed represents the meridional wind at the target height.

[0057] Step S50: Determine the collision frequency of the F region of the ionosphere based on the target diffusion speed.

[0058] Among them, the collision frequency can be calculated by the following formula:

[0059] Among them, represents the collision frequency, k represents the Boltzmann constant, represents the ion temperature, represents the electron temperature, represents the magnetic dip angle I the sine value of, represents the ion mass, represents the target diffusion speed, represents the electron density, represents the partial derivative symbol, represents the target height, and g represents the acceleration due to gravity.

[0060] In the embodiment of the present application, based on the target diffusion speed obtained in the above steps, the collision frequency of the F region of the ionosphere can be further calculated.

[0061] In order to verify the effectiveness of the method described in the present application, the following verification experiment is provided in the embodiment of the present application.

[0062] From November 2023 to October 2024, the Sanya Incoherent Scatter Radar conducted a one-year continuous experiment using a 480-µs long pulse waveform. The Sanya Incoherent Scatter Radar is located in Sanya and operates in the UHF band of 430 - 450 MHz, with a peak power exceeding 4 MW (for references, see Yue, X., Wan, W., Ning, B., Jin, L., Ding, F., Zhao, B., et al. (2022). Development of the Sanya incoherent scatter radar and preliminary results. Journal of Geophysical Research: Space Physics, 127(8), e2022JA030451. https: / / doi.org / 10.1029 / 2022JA030451; Yue, X., Ning, B., Jin, L., & Wang, C. (2024). A tristatic phased array radar system in China. Nature Astronomy, 8(5), 673 - 673. http: / / doi.org / 10.1038 / s41550-024-02274-z).

[0063] Please refer to Figures 2 - 4 the observed data of the Sanya Incoherent Scatter Radar on November 24, 2023, shown below, where Figure 2 is the time series diagram of the zonal wind speed corresponding to the height where the diffusion velocity is zero, Figure 3 is the time series diagram of the diffusion velocity at the target height, Figure 4 is the time series diagram of the collision frequency coefficient within 10 km of the target height. It can be seen that the collision frequency changes gradually over time.

[0064] It should be noted that the collision frequency can be obtained through the collision frequency coefficient. Using the collision frequency coefficient as the experimental result data is for comparison with the results obtained by the momentum balance method.

[0065] Furthermore, the momentum balance method adopted in previous literature was used for verification. According to the FPI data at the same location and the collision frequency coefficient obtained at night by the Sanya Incoherent Scatter Radar using the momentum balance method (marked as FPI-ISR), please refer to Figure 5The comparison chart of the collision frequency coefficients from November 2023 to January 2024 as shown, compares the time series chart of the collision frequency coefficients obtained in the embodiments of the present application (marked as ISR). It can be seen from the figure that the consistency between the two is good, which proves the effectiveness of the method described in the present application.

[0066] Previous studies usually could only obtain the collision frequency during the day or only at night. The present application uses the Sanya incoherent scatter radar to provide 24-hour accurate collision frequency results and changes using a new method, and does not rely on other observational data.

[0067] Although the various steps are described in the above order in the above embodiments, those skilled in the art can understand that in order to achieve the effects of the present embodiment, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in reverse order, and these simple changes are all within the protection scope of the present application.

[0068] Please refer to Figure 6 , the system for extracting the collision frequency of the F region of the ionosphere based on incoherent scatter radar in the second embodiment of the present application includes: an ionospheric parameter acquisition module 100, an ion vector velocity acquisition module 200, a diffusion velocity zero value height determination module 300, a target diffusion velocity determination module 400, and a collision frequency determination module 500.

[0069] The ionospheric parameter acquisition module 100 is used to acquire the ionospheric parameters of the F region of the ionosphere based on the incoherent scatter radar, where the ionospheric parameters include electron density, electron temperature, ion temperature, and ion line-of-sight velocity; The ion vector velocity acquisition module 200 is used to acquire the ion vector velocity according to the ion line-of-sight velocities in multiple line-of-sight directions; The diffusion velocity zero value height determination module 300 is used to determine the diffusion velocity zero value height based on the electron density, electron temperature, ion temperature, and ion mass when the diffusion velocity of ions in the ionosphere is 0; The target diffusion velocity determination module 400 is used to determine the target diffusion velocity at the target height based on the meridional wind, ion vector velocity, and magnetic dip angle at the diffusion velocity zero value height, where the target height is the height above the diffusion velocity zero value height; The collision frequency determination module 500 is used to determine the collision frequency of the F region of the ionosphere based on the target diffusion velocity.

[0070] Those skilled in the art to which the present application pertains can clearly understand that for the convenience and brevity of description, the specific working processes and related descriptions of the above-described system can refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated herein.

[0071] It should be noted that the system for extracting the ionospheric F-region collision frequency based on incoherent scatter radar provided in the above embodiments is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules according to needs, that is, the modules or steps in the embodiments of the present application can be further decomposed or combined. For example, the modules in the above embodiments can be combined into one module, or further split into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present application are only for distinguishing each module or step, and are not regarded as an improper limitation of the present application.

[0072] An electronic device according to the third embodiment of the present application includes: At least one processor; and A memory communicatively connected to at least one of the processors; wherein, The memory stores instructions executable by the processor, and the instructions are used to be executed by the processor to implement the above method for extracting the ionospheric F-region collision frequency based on incoherent scatter radar.

[0073] A computer-readable storage medium according to the fourth embodiment of the present application stores computer instructions, and the computer instructions are used to be executed by the computer to implement the above method for extracting the ionospheric F-region collision frequency based on incoherent scatter radar.

[0074] A computer program product according to the fifth embodiment of the present application, when running on an electronic device, causes the electronic device to execute the above method for extracting the ionospheric F-region collision frequency based on incoherent scatter radar.

[0075] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes and related descriptions of the above-described electronic device, computer-readable storage medium, and computer program product can refer to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0076] Those skilled in the art should be able to realize that the modules and method steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of both. The programs corresponding to the software modules and method steps can be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the technical field. To clearly illustrate the interchangeability of electronic hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in the form of electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0077] Reference is made below to Figure 7 , which shows a schematic structural diagram of a computer system of a server for implementing the method, system, and device embodiments of this application. Figure 7 The server shown is only an example and should not impose any limitations on the functions and usage scope of the embodiments of this application.

[0078] As Figure 7 shown, the computer system includes a central processing unit (CPU, Central Processing Unit) 701, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM, Read Only Memory) 702 or the program loaded from the storage section 708 into the random access memory (RAM, Random Access Memory) 703. In the RAM 703, various programs and data required for system operation are also stored. The CPU 701, ROM 702, and RAM 703 are connected to each other through a bus 704. The input / output (I / O, Input / Output) interface 705 is also connected to the bus 704.

[0079] The following components are connected to the I / O interface 705: an input section 706 including a keyboard, a mouse, etc.; an output section 707 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc. and a speaker, etc.; a storage section 708 including a hard disk, etc.; and a communication section 709 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 709 performs communication processing via a network such as the Internet. A drive 710 is also connected to the I / O interface 705 as needed. A removable medium 711 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc. is mounted on the drive 710 as needed so that a computer program read therefrom is installed into the storage section 708 as needed.

[0080] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product that includes a computer program carried on a computer-readable medium, and the computer program contains program codes for performing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 709, and / or installed from the removable medium 711. When the computer program is executed by the central processing unit (CPU) 701, the above functions defined in the method of the present application are executed. It should be noted that the above computer-readable medium in the present application can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, the computer-readable storage medium can be any tangible medium that contains or stores a program, and the program can be used by or in combination with an instruction execution system, apparatus, or device. In the present application, the computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, in which the computer-readable program code is carried. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium, and the computer-readable medium can send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted by any suitable medium, including but not limited to: wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0081] Computer program code for performing the operations of this application can be written in one or more programming languages or combinations thereof. The above-mentioned programming languages include object-oriented programming languages such as Java, Smalltalk, C++, and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, executed as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any kind of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (for example, by using an Internet service provider to connect through the Internet).

[0082] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code that contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than that marked in the accompanying drawings. For example, two consecutively represented blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, as well as combinations of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system that performs the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0083] The terms "first", "second", etc. are used to distinguish similar objects, rather than to describe or represent a specific order or sequence.

[0084] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or device / equipment that comprises a series of elements includes not only those elements but also other elements that are not explicitly listed, or also includes elements that are inherent to those processes, methods, articles, or devices / equipment.

[0085] So far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principle of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present application.

Claims

1. A method for extracting the collision frequency of the ionospheric F region based on incoherent scatter radar, characterized in that Including: Step S10: Obtain ionospheric parameters of the F region of the ionosphere based on an incoherent scatter radar, where the ionospheric parameters include electron density, electron temperature, ion temperature, and ion line-of-sight velocity; Step S20: Obtain the ion vector velocity according to the ion line-of-sight velocities in multiple line-of-sight directions; Step S30: When the diffusion velocity of ions in the ionosphere is 0, determine the zero diffusion velocity height based on the electron density, electron temperature, ion temperature, and ion mass; Step S40: Determine the target diffusion velocity at the target height based on the meridional wind at the zero diffusion velocity height, the ion vector velocity, and the magnetic dip angle, where the target height is a height above the zero diffusion velocity height; Step S50: Determine the collision frequency of the F region of the ionosphere based on the target diffusion velocity.

2. The method for extracting the collision frequency of the ionospheric F region based on incoherent scatter radar according to claim 1, wherein The determination of the zero diffusion velocity height includes: Set the diffusion velocity in the diffusion formula to zero, and determine the zero diffusion velocity height according to the electron density, electron temperature, ion temperature, and ion mass in the diffusion formula; Wherein, the diffusion formula is: ； Among them, represents the diffusion velocity, k represents the Boltzmann constant, represents the ion temperature, represents the electron temperature, represents the magnetic dip angle I the sine value of, represents the ion mass, represents the collision frequency, represents the electron density, represents the partial derivative symbol, h represents height, and g represents the acceleration due to gravity.

3. The method for extracting the collision frequency of the ionospheric F region based on incoherent scatter radar according to claim 1, wherein The determination of the target diffusion velocity at the target height includes: ； Among them, represents the target diffusion velocity, represents the velocity along the magnetic field line direction, represents the meridional wind at the zero value height of the diffusion velocity, cos I represents the cosine value of the magnetic dip angle, where the velocity along the magnetic field line direction is one of the ion vector velocities.

4. The method for extracting the collision frequency of the ionospheric F region based on incoherent scatter radar according to claim 3, characterized in that The meridional wind at the zero diffusion velocity height includes: ； Among them, represents the velocity along the magnetic field line direction at the zero value height of the diffusion velocity.

5. The method for extracting the collision frequency of the ionospheric F region based on incoherent scatter radar according to claim 1, characterized in that, The determination of the collision frequency of the F region of the ionosphere based on the target diffusion velocity includes: ； Among them, represents the collision frequency, k represents the Boltzmann constant, represents the ion temperature, represents the electron temperature, represents the sine value of the magnetic dip angle I of, represents the ion mass, represents the target diffusion velocity, represents the electron density, represents the partial derivative symbol, represents the target height, and g represents the acceleration due to gravity.

6. The method for extracting the collision frequency of the ionospheric F region based on incoherent scatter radar according to claim 1, characterized in that, The obtaining of the ionospheric parameters of the F region of the ionosphere based on an incoherent scatter radar includes: Obtain the scattered signal generated by the incoherent scatter radar emitting electromagnetic waves to the ionosphere; At different heights, fit the theoretical power spectrum and the measured power spectrum of the scattered signal; When the fitting error between the theoretical power spectrum and the measured power spectrum is the smallest, obtain the ionospheric parameters.

7. The method for extracting the collision frequency of the ionospheric F region based on incoherent scatter radar according to claim 1, characterized in that The obtaining of the ion vector velocity according to the ion line-of-sight velocities in multiple line-of-sight directions includes: According to the relationship between the ion line-of-sight velocity and the ion vector velocity in the geomagnetic coordinate system, and combining the ion line-of-sight velocities in different directions, perform least squares fitting to obtain the ion vector velocity.

8. A system for extracting the collision frequency of the ionospheric F region based on an incoherent scatter radar, characterized in that, Including: An ionospheric parameter acquisition module for obtaining ionospheric parameters of the F region of the ionosphere based on an incoherent scatter radar, where the ionospheric parameters include electron density, electron temperature, ion temperature, and ion line-of-sight velocity; An ion vector velocity acquisition module for obtaining the ion vector velocity according to the ion line-of-sight velocities in multiple line-of-sight directions; A zero diffusion velocity height determination module for determining the zero diffusion velocity height based on the electron density, electron temperature, ion temperature, and ion mass when the diffusion velocity of ions in the ionosphere is 0; A target diffusion velocity determination module for determining the target diffusion velocity at the target height based on the meridional wind at the zero diffusion velocity height, the ion vector velocity, and the magnetic dip angle, where the target height is a height above the zero diffusion velocity height; A collision frequency determination module for determining the collision frequency of the F region of the ionosphere based on the target diffusion velocity.

9. An electronic device, characterized in that, Including: At least one processor; And A memory communicatively connected to at least one of the processors; wherein, The memory stores instructions executable by the processor, and the instructions are used to be executed by the processor to implement the method for extracting the collision frequency of the ionospheric F region based on incoherent scatter radar according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions, and the computer instructions are used to be executed by the computer to implement the method for extracting the collision frequency of the ionospheric F region based on incoherent scatter radar according to any one of claims 1-7.

Images