The polar magnetic fields of the Sun play an important role in governing solar activity and powering fast solar wind.However,because our view of the Sun is limited in the ecliptic plane,the polar regions remain largel...The polar magnetic fields of the Sun play an important role in governing solar activity and powering fast solar wind.However,because our view of the Sun is limited in the ecliptic plane,the polar regions remain largely uncharted.Using the high spatial resolution and polarimetric precision vector magnetograms observed by Hinode from 2012 to 2021,we investigate the long-term variation of the magnetic fields in polar caps at different latitudes.The Hinode magnetic measurements show that the polarity reversal processes in the north and south polar caps are non-simultaneous.The variation of the averaged radial magnetic flux density reveals that,in each polar cap,the polarity reversal is completed successively from the 70°latitude to the pole,reflecting a poleward magnetic flux migration therein.These results clarify the polar magnetic polarity reversal process at different latitudes.展开更多
With the growing significance of space weather forecasting,multi-layer magnetic and helioseismic telescopes are emerging as a key area of research.However,owing to the diverse operational processes and sophisticated h...With the growing significance of space weather forecasting,multi-layer magnetic and helioseismic telescopes are emerging as a key area of research.However,owing to the diverse operational processes and sophisticated hardware configurations of these devices,there is an urgent need for efficient autonomous observation capabilities.An autonomous Master Control System(MCS)can ensure efficient performance,data consistency,and stability,and the prototype presented here adopts a microservices architecture,breaking down the hardware into multiple subsystems and converting their functions into individual services.A central decision-making system leads the operations,supported by three auxiliary systems and three device control systems.Through inter-subsystem service calls,it achieves rapid imaging and spectroscopic monitoring.To verify system stability and observation efficiency,the system was tested on the Solar Full-disk Multi-layer Magnetograph.Experimental results verify this system can operate automatically for 4 consecutive months,acquire photospheric vector magnetic and Doppler velocity fields within a 15-minute interval,and measure chromospheric longitudinal magnetic and Doppler velocity fields in under 180 s.This ensures consistent and stable solar monitoring and serves as a practical methodological benchmark for the development of similar devices.展开更多
The Solar Upper Transition Region Imager(SUTRI)onboard the Space Advanced Technology demonstration satellite(SATech-01),which was launched to a Sun-synchronous orbit at a height of~500 km in 2022 July,aims to test the...The Solar Upper Transition Region Imager(SUTRI)onboard the Space Advanced Technology demonstration satellite(SATech-01),which was launched to a Sun-synchronous orbit at a height of~500 km in 2022 July,aims to test the on-orbit performance of our newly developed Sc/Si multi-layer reflecting mirror and the 2k×2k EUV CMOS imaging camera and to take full-disk solar images at the Ne VII 46.5 nm spectral line with a filter width of~3 nm.SUTRI employs a Ritchey-Chrétien optical system with an aperture of 18 cm.The on-orbit observations show that SUTRI images have a field of view of~416×416 and a moderate spatial resolution of~8″without an image stabilization system.The normal cadence of SUTRI images is 30 s and the solar observation time is about16 hr each day because the earth eclipse time accounts for about 1/3 of SATech-01's orbit period.Approximately15 GB data is acquired each day and made available online after processing.SUTRI images are valuable as the Ne VII 46.5 nm line is formed at a temperature regime of~0.5 MK in the solar atmosphere,which has rarely been sampled by existing solar imagers.SUTRI observations will establish connections between structures in the lower solar atmosphere and corona,and advance our understanding of various types of solar activity such as flares,filament eruptions,coronal jets and coronal mass ejections.展开更多
An infrared solar spectrum observed by ground-based telescopes is seriously affected by the background radiation both from the telescope and sky,relative to the visible wavelengths.Its accuracy is also influenced by t...An infrared solar spectrum observed by ground-based telescopes is seriously affected by the background radiation both from the telescope and sky,relative to the visible wavelengths.Its accuracy is also influenced by the spectral resolution of the Fourier transform spectrometer.In the paper,we developed a CO_(2)gas cell and installed it in the sample compartment to calibrate the spectral resolution of the Bruker IFS-125HR at infrared wavelengths.The measured spectral resolution is 0.00342±0.00086 cm^(-1)and 0.0059±0.00024 cm^(-1)at the wavenumbers of798 cm^(-1)and 2136 cm^(-1),respectively.We also updated a fully reflective sunlight feeding system to observe the solar spectrum near CO 4.66μm and Mg I 12.32μm.By quickly pointing the sunlight feeding system about1 degree away from the solar disk center,we are able to measure the background radiation from the telescope and the sky at Huairou Solar Observing Station.After removing the background radiation,our observed solar spectrum at CO 4.66μm is consistent with that from the National Solar Observatory.The Mg I 12.32μm working line selected by the Accurate Infrared Magnetic Field Measurements of the Sun(AIMS)project is also identified.Our method is helpful not only for the spectral resolution calibration and background radiation correction of AIMS but also for other infrared astronomical telescopes.展开更多
The Solar Upper Transition Region Imager(SUTRI)focuses on the solar transition region to achieve dynamic imaging observation of the upper transition region.In this paper,we report the optical system design,mechanical ...The Solar Upper Transition Region Imager(SUTRI)focuses on the solar transition region to achieve dynamic imaging observation of the upper transition region.In this paper,we report the optical system design,mechanical design,ultrasmooth mirror manufacture and measurement,EUV multilayer film coating,prelaunch installation and calibration for the SUTRI payload at IPOE,Tongji University.Finally,the SUTRI carried by the SATech-01 satellite was successfully set to launch.All functions of this telescope were normal,and the observation results obtained in orbit were consistent with the design.展开更多
Sky clouds affect solar observations significantly.Their shadows obscure the details of solar features in observed images.Cloud-covered solar images are difficult to be used for further research without pre-processing...Sky clouds affect solar observations significantly.Their shadows obscure the details of solar features in observed images.Cloud-covered solar images are difficult to be used for further research without pre-processing.In this paper,the solar image cloud removing problem is converted to an image-to-image translation problem,with a used algorithm of the Pixel to Pixel Network(Pix2Pix),which generates a cloudless solar image without relying on the physical scattering model.Pix2Pix is consists of a generator and a discriminator.The generator is a well-designed U-Net.The discriminator uses PatchGAN structure to improve the details of the generated solar image,which guides the generator to create a pseudo realistic solar image.The image generation model and the training process are optimized,and the generator is jointly trained with the discriminator.So the generation model which can stably generate cloudless solar image is obtained.Extensive experiment results on Huairou Solar Observing Station,National Astronomical Observatories,and Chinese Academy of Sciences(HSOS,NAOC and CAS)datasets show that Pix2Pix is superior to the traditional methods based on physical prior knowledge in peak signal-to-noise ratio,structural similarity,perceptual index,and subjective visual effect.The result of the PSNR,SSIM and PI are 27.2121 dB,0.8601 and 3.3341.展开更多
Extreme ultraviolet(EUV)observations are widely used in solar activity research and space weather forecasting since they can observe both the solar eruptions and the source regions of the solar wind.Flat field process...Extreme ultraviolet(EUV)observations are widely used in solar activity research and space weather forecasting since they can observe both the solar eruptions and the source regions of the solar wind.Flat field processing is indispensable to remove the instrumental non-uniformity of a solar EUV imager in producing high-quality scientific data from original observed data.FengYun-3E(FY-3E)is a meteorological satellite operated in a Sunsynchronous orbit,and the routine EUV imaging data from the Solar X-ray and Extreme Ultraviolet Imager(X-EUVI)onboard FY-3E has the characteristic of concentric rotation.Taking advantage of the concentric rotation,we propose a post-hoc flat field measurement method for its EUV 195A channel in this paper.This method removes the small-scale and time-varying component of coronal activities by taking the median value for each pixel along the time axis of a concentric rotation data cube,and then derives the large-scale and invariable component of the quiet coronal radiation,and finally generates a flat field image.The flat field can be generated with cadences from hundreds of minutes(one orbit)to several days.Higher flat field accuracy can be achieved by employing more data.Further analysis shows that our method is able to measure the instrumental spot-like nonuniformity possibly caused by contamination on the detector,which mostly disappears after the in-orbit selfcleaning process.It can also measure the quasi-periodic grid-like non-uniformity,possibly from the obscuration of the support mesh on the rear filter.After flat field correction,these instrumental non-uniformities from the original data are effectively removed.Moreover,the X-EUVI 195A data after dark and flat field corrections are consistent with the 193A imaging data from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory,verifying the suitability of the method.The post-hoc method does not occupy observation time,which is advantageous for space weather operations.Our method is not only suitable for FY-3E/X-EUVI but also a candidate method for the flat field measurement of future solar EUV telescopes.展开更多
基金supported by the National Key R&D Programs of China(2019YFA0405000,2022YFF0503800,2022YFF0503000)the Strategic Priority Research Programs of the Chinese Academy of Sciences(XDB0560000,XDB41000000)+1 种基金the National Natural Science Foundations of China(NSFC,Grant Nos.12173005,12273060,12350004,12273061,12222306,and 12073001)the Youth Innovation Promotion Association CAS,and Yunnan Academician Workstation of Wang Jingxiu(No.202005AF150025)。
文摘The polar magnetic fields of the Sun play an important role in governing solar activity and powering fast solar wind.However,because our view of the Sun is limited in the ecliptic plane,the polar regions remain largely uncharted.Using the high spatial resolution and polarimetric precision vector magnetograms observed by Hinode from 2012 to 2021,we investigate the long-term variation of the magnetic fields in polar caps at different latitudes.The Hinode magnetic measurements show that the polarity reversal processes in the north and south polar caps are non-simultaneous.The variation of the averaged radial magnetic flux density reveals that,in each polar cap,the polarity reversal is completed successively from the 70°latitude to the pole,reflecting a poleward magnetic flux migration therein.These results clarify the polar magnetic polarity reversal process at different latitudes.
基金supported by the National Key R&D Program of China (2022YFF0503800)the Chinese Meridian Project,the National Natural Science Foundation of China (11427901)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA15320102)the Youth Innovation Promotion Association (2022057).
文摘With the growing significance of space weather forecasting,multi-layer magnetic and helioseismic telescopes are emerging as a key area of research.However,owing to the diverse operational processes and sophisticated hardware configurations of these devices,there is an urgent need for efficient autonomous observation capabilities.An autonomous Master Control System(MCS)can ensure efficient performance,data consistency,and stability,and the prototype presented here adopts a microservices architecture,breaking down the hardware into multiple subsystems and converting their functions into individual services.A central decision-making system leads the operations,supported by three auxiliary systems and three device control systems.Through inter-subsystem service calls,it achieves rapid imaging and spectroscopic monitoring.To verify system stability and observation efficiency,the system was tested on the Solar Full-disk Multi-layer Magnetograph.Experimental results verify this system can operate automatically for 4 consecutive months,acquire photospheric vector magnetic and Doppler velocity fields within a 15-minute interval,and measure chromospheric longitudinal magnetic and Doppler velocity fields in under 180 s.This ensures consistent and stable solar monitoring and serves as a practical methodological benchmark for the development of similar devices.
基金supported by the National Natural Science Foundation of China(NSFC)under Grants 11825301,12003016,12073077the National Key R&D Program of China No.2021YFA0718600+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences with the Grant No.XDA15018400the Youth Innovation Promotion Association of CAS(2023061)。
文摘The Solar Upper Transition Region Imager(SUTRI)onboard the Space Advanced Technology demonstration satellite(SATech-01),which was launched to a Sun-synchronous orbit at a height of~500 km in 2022 July,aims to test the on-orbit performance of our newly developed Sc/Si multi-layer reflecting mirror and the 2k×2k EUV CMOS imaging camera and to take full-disk solar images at the Ne VII 46.5 nm spectral line with a filter width of~3 nm.SUTRI employs a Ritchey-Chrétien optical system with an aperture of 18 cm.The on-orbit observations show that SUTRI images have a field of view of~416×416 and a moderate spatial resolution of~8″without an image stabilization system.The normal cadence of SUTRI images is 30 s and the solar observation time is about16 hr each day because the earth eclipse time accounts for about 1/3 of SATech-01's orbit period.Approximately15 GB data is acquired each day and made available online after processing.SUTRI images are valuable as the Ne VII 46.5 nm line is formed at a temperature regime of~0.5 MK in the solar atmosphere,which has rarely been sampled by existing solar imagers.SUTRI observations will establish connections between structures in the lower solar atmosphere and corona,and advance our understanding of various types of solar activity such as flares,filament eruptions,coronal jets and coronal mass ejections.
基金supported by the National Key R&D Program of China(2021YFA1600500)the Youth Innovation Promotion Association CAS(2023061)the National Natural Science Foundation of China(NSFC,Grant Nos.12003051,11427901)。
文摘An infrared solar spectrum observed by ground-based telescopes is seriously affected by the background radiation both from the telescope and sky,relative to the visible wavelengths.Its accuracy is also influenced by the spectral resolution of the Fourier transform spectrometer.In the paper,we developed a CO_(2)gas cell and installed it in the sample compartment to calibrate the spectral resolution of the Bruker IFS-125HR at infrared wavelengths.The measured spectral resolution is 0.00342±0.00086 cm^(-1)and 0.0059±0.00024 cm^(-1)at the wavenumbers of798 cm^(-1)and 2136 cm^(-1),respectively.We also updated a fully reflective sunlight feeding system to observe the solar spectrum near CO 4.66μm and Mg I 12.32μm.By quickly pointing the sunlight feeding system about1 degree away from the solar disk center,we are able to measure the background radiation from the telescope and the sky at Huairou Solar Observing Station.After removing the background radiation,our observed solar spectrum at CO 4.66μm is consistent with that from the National Solar Observatory.The Mg I 12.32μm working line selected by the Accurate Infrared Magnetic Field Measurements of the Sun(AIMS)project is also identified.Our method is helpful not only for the spectral resolution calibration and background radiation correction of AIMS but also for other infrared astronomical telescopes.
基金the National Key R&D Program of China(2022YFF0709101)the National Natural Science Foundation of China(NSFC)under grant Nos.61621001,62105244,12003016 and 12204353.
文摘The Solar Upper Transition Region Imager(SUTRI)focuses on the solar transition region to achieve dynamic imaging observation of the upper transition region.In this paper,we report the optical system design,mechanical design,ultrasmooth mirror manufacture and measurement,EUV multilayer film coating,prelaunch installation and calibration for the SUTRI payload at IPOE,Tongji University.Finally,the SUTRI carried by the SATech-01 satellite was successfully set to launch.All functions of this telescope were normal,and the observation results obtained in orbit were consistent with the design.
基金Funding for this study was received from the open project of CAS Key Laboratory of Solar Activity(Grant No:KLSA202114)and the crossdiscipline research project of Minzu University of China(2020MDJC08).
文摘Sky clouds affect solar observations significantly.Their shadows obscure the details of solar features in observed images.Cloud-covered solar images are difficult to be used for further research without pre-processing.In this paper,the solar image cloud removing problem is converted to an image-to-image translation problem,with a used algorithm of the Pixel to Pixel Network(Pix2Pix),which generates a cloudless solar image without relying on the physical scattering model.Pix2Pix is consists of a generator and a discriminator.The generator is a well-designed U-Net.The discriminator uses PatchGAN structure to improve the details of the generated solar image,which guides the generator to create a pseudo realistic solar image.The image generation model and the training process are optimized,and the generator is jointly trained with the discriminator.So the generation model which can stably generate cloudless solar image is obtained.Extensive experiment results on Huairou Solar Observing Station,National Astronomical Observatories,and Chinese Academy of Sciences(HSOS,NAOC and CAS)datasets show that Pix2Pix is superior to the traditional methods based on physical prior knowledge in peak signal-to-noise ratio,structural similarity,perceptual index,and subjective visual effect.The result of the PSNR,SSIM and PI are 27.2121 dB,0.8601 and 3.3341.
基金supported by the National Key R&D Program of China(2021YFA0718600)the National Natural Science Foundations of China(NSFC,Grant Nos.41931073,41774195)+2 种基金Ten-thousand Talents Program of JingSong Wang,and the Specialized Research Fund for State Key Laboratoriessupported by the Strategic Priority Research Program of the Chinese Academy of Sciences,Grant No.XDA 15018400supported by the China Postdoctoral Science Foundation(2021M700246)。
文摘Extreme ultraviolet(EUV)observations are widely used in solar activity research and space weather forecasting since they can observe both the solar eruptions and the source regions of the solar wind.Flat field processing is indispensable to remove the instrumental non-uniformity of a solar EUV imager in producing high-quality scientific data from original observed data.FengYun-3E(FY-3E)is a meteorological satellite operated in a Sunsynchronous orbit,and the routine EUV imaging data from the Solar X-ray and Extreme Ultraviolet Imager(X-EUVI)onboard FY-3E has the characteristic of concentric rotation.Taking advantage of the concentric rotation,we propose a post-hoc flat field measurement method for its EUV 195A channel in this paper.This method removes the small-scale and time-varying component of coronal activities by taking the median value for each pixel along the time axis of a concentric rotation data cube,and then derives the large-scale and invariable component of the quiet coronal radiation,and finally generates a flat field image.The flat field can be generated with cadences from hundreds of minutes(one orbit)to several days.Higher flat field accuracy can be achieved by employing more data.Further analysis shows that our method is able to measure the instrumental spot-like nonuniformity possibly caused by contamination on the detector,which mostly disappears after the in-orbit selfcleaning process.It can also measure the quasi-periodic grid-like non-uniformity,possibly from the obscuration of the support mesh on the rear filter.After flat field correction,these instrumental non-uniformities from the original data are effectively removed.Moreover,the X-EUVI 195A data after dark and flat field corrections are consistent with the 193A imaging data from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory,verifying the suitability of the method.The post-hoc method does not occupy observation time,which is advantageous for space weather operations.Our method is not only suitable for FY-3E/X-EUVI but also a candidate method for the flat field measurement of future solar EUV telescopes.
