Indirect X-ray modulation imaging has been adopted in a number of solar missions and provided reconstructed X-ray images of solar flares that are of great scientific importance.However,the assessment of the image qual...Indirect X-ray modulation imaging has been adopted in a number of solar missions and provided reconstructed X-ray images of solar flares that are of great scientific importance.However,the assessment of the image quality of the reconstruction is still difficult,which is particularly useful for scheme design of X-ray imaging systems,testing and improvement of imaging algorithms,and scientific research of X-ray sources.Currently,there is no specified method to quantitatively evaluate the quality of X-ray image reconstruction and the point-spread function(PSF)of an X-ray imager.In this paper,we propose percentage proximity degree(PPD)by considering the imaging characteristics of X-ray image reconstruction and in particular,sidelobes and their effects on imaging quality.After testing a variety of imaging quality assessments in six aspects,we utilized the technique for order preference by similarity to ideal solution to the indices that meet the requirements.Then we develop the final quality index for X-ray image reconstruction,QuIX,which consists of the selected indices and the new PPD.QuIX performs well in a series of tests,including assessment of instrument PSF and simulation tests under different grid configurations,as well as imaging tests with RHESSI data.It is also a useful tool for testing of imaging algorithms,and determination of imaging parameters for both RHESSI and ASO-S/Hard X-ray Imager,such as field of view,beam width factor,and detector selection.展开更多
The in-flight calibration and performance of the Solar Disk Imager(SDI),which is a pivotal instrument of the LyαSolar Telescope onboard the Advanced Space-based Solar Observatory mission,suggested a much lower spatia...The in-flight calibration and performance of the Solar Disk Imager(SDI),which is a pivotal instrument of the LyαSolar Telescope onboard the Advanced Space-based Solar Observatory mission,suggested a much lower spatial resolution than expected.In this paper,we developed the SDI point-spread function(PSF)and Image Bivariate Optimization Algorithm(SPIBOA)to improve the quality of SDI images.The bivariate optimization method smartly combines deep learning with optical system modeling.Despite the lack of information about the real image taken by SDI and the optical system function,this algorithm effectively estimates the PSF of the SDI imaging system directly from a large sample of observational data.We use the estimated PSF to conduct deconvolution correction to observed SDI images,and the resulting images show that the spatial resolution after correction has increased by a factor of more than three with respect to the observed ones.Meanwhile,our method also significantly reduces the inherent noise in the observed SDI images.The SPIBOA has now been successfully integrated into the routine SDI data processing,providing important support for the scientific studies based on the data.The development and application of SPIBOA also paves new ways to identify astronomical telescope systems and enhance observational image quality.Some essential factors and precautions in applying the SPIBOA method are also discussed.展开更多
In this paper,we perform a follow-up investigation of the solar eruption originating from active region 13575 on 2024 February 9.The primary eruption of a hot channel generates an X3.4 class flare,a full-halo coronal ...In this paper,we perform a follow-up investigation of the solar eruption originating from active region 13575 on 2024 February 9.The primary eruption of a hot channel generates an X3.4 class flare,a full-halo coronal mass ejection(CME),and an extreme-ultraviolet(EUV)wave.Interaction between the wave and a quiescent prominence(QP)leads to a large-amplitude,transverse oscillation of QP.After the transverse oscillation,QP loses equilibrium and rises up.The ascending motion of the prominence is coherently detected and tracked up to∼1.68 R_(⊙)by the Solar UltraViolet Imager onboard the GOES-16 spacecraft and up to∼2.2 R_(⊙)by the Solar Corona Imager(SCI_UV)of the LyαSolar Telescope onboard the ASO-S spacecraft.The velocity increases linearly from 12.3 to 68.5 km s^(−1)at 18:30 UT.The sympathetic eruption of QP drives the second CME with a typical three-part structure.The bright core comes from the eruptive prominence,which could be further observed up to∼3.3 R_(⊙) by the Large Angle Spectroscopic Coronagraph onboard the Solar and Heliospheric Observatory mission.The leading edge of the second CME accelerates continuously from∼120 to∼277 km s^(−1).The EUV wave plays an important role in linking the primary eruption with the sympathetic eruption.展开更多
The magnetic fields and dynamical processes in the solar polar regions play a crucial role in the solar magnetic cycle and in supplying mass and energy to the fast solar wind,ultimately being vital in controlling sola...The magnetic fields and dynamical processes in the solar polar regions play a crucial role in the solar magnetic cycle and in supplying mass and energy to the fast solar wind,ultimately being vital in controlling solar activities and driving space weather.Despite numerous efforts to explore these regions,to date no imaging observations of the Sun's poles have been achieved from vantage points out of the ecliptic plane,leaving their behavior and evolution poorly understood.This observation gap has left three top-level scientific questions unanswered:How does the solar dynamo work and drive the solar magnetic cycle?What drives the fast solar wind?How do space weather processes globally originate from the Sun and propagate throughout the solar system?The Solar Polarorbit Observatory(SPO)mission,a solar polar exploration spacecraft,is proposed to address these three unanswered scientific questions by imaging the Sun's poles from high heliolatitudes.In order to achieve its scientific goals,SPO will carry six remote-sensing and four in-situ instruments to measure the vector magnetic fields and Doppler velocity fields in the photosphere,to observe the Sun in the extreme ultraviolet,X-ray,and radio wavelengths,to image the corona and the heliosphere up to 45 R_(s),and to perform in-situ detection of magnetic fields,and low-and high-energy particles in the solar wind.The SPO mission is capable of providing critical vector magnetic fields and Doppler velocities of the polar regions to advance our understanding of the origin of the solar magnetic cycle,providing unprecedented imaging observations of the solar poles alongside in-situ measurements of charged particles and magnetic fields from high heliolatitudes to unveil the mass and energy supply that drive the fast solar wind,and providing observational constraints for improving our ability to model and predict the three-dimensional(3D)structures and propagation of space weather events.展开更多
A 50 mm balloon-borne white-light coronagraph(BBWLC)to observe white-light solar corona over the altitude range from 1.08 R_(⊙)to 1.50 R_(⊙)has recently been indigenously developed by Yunnan Observatories in collabo...A 50 mm balloon-borne white-light coronagraph(BBWLC)to observe white-light solar corona over the altitude range from 1.08 R_(⊙)to 1.50 R_(⊙)has recently been indigenously developed by Yunnan Observatories in collaboration with Shandong University(in Weihai)and Changchun Institute of Optics,Fine Mechanics and Physics,which will significantly improve the ability of China to detect and measure the inner corona.On 2022 October 4,its first scientific flight took place at the Dachaidan area in Qinghai province of China.We briefly describe the BBWLC mission including its optical design,mechanical structure,pointing system,the first flight and results associated with the data processing approach.Preliminary analysis of the data shows that BBWLC imaged the K-corona with three streamer structures on the west limb of the Sun.To further confirm the coronal signals obtained by BBWLC,comparisons were made with observations of the K-coronagraph of the High Altitude Observatory and the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory.We conclude that BBWLC eventually observed the white-light corona in its first scientific flight.展开更多
Solar flares are one of the strongest outbursts of solar activity,posing a serious threat to Earth’s critical infrastructure,such as communications,navigation,power,and aviation.Therefore,it is essential to accuratel...Solar flares are one of the strongest outbursts of solar activity,posing a serious threat to Earth’s critical infrastructure,such as communications,navigation,power,and aviation.Therefore,it is essential to accurately predict solar flares in order to ensure the safety of human activities.Currently,the research focuses on two directions:first,identifying predictors with more physical information and higher prediction accuracy,and second,building flare prediction models that can effectively handle complex observational data.In terms of flare observability and predictability,this paper analyses multiple dimensions of solar flare observability and evaluates the potential of observational parameters in prediction.In flare prediction models,the paper focuses on data-driven models and physical models,with an emphasis on the advantages of deep learning techniques in dealing with complex and high-dimensional data.By reviewing existing traditional machine learning,deep learning,and fusion methods,the key roles of these techniques in improving prediction accuracy and efficiency are revealed.Regarding prevailing challenges,this study discusses the main challenges currently faced in solar flare prediction,such as the complexity of flare samples,the multimodality of observational data,and the interpretability of models.The conclusion summarizes these findings and proposes future research directions and potential technology advancement.展开更多
Major solar plasma disturbances are subjected to Lomb-Scargle periodogram and wavelet analysis to determine the occurrence frequency.These disruptions include interplanetary coronal mass ejection,sudden storm commence...Major solar plasma disturbances are subjected to Lomb-Scargle periodogram and wavelet analysis to determine the occurrence frequency.These disruptions include interplanetary coronal mass ejection,sudden storm commencement,high-speed streams,corotating interaction regions,interplanetary shocks and Forbush decreases.We included information on all of the aforementioned solar disturbances for the last six solar cycles,from 1965 to 2023,for this study.Our findings reveal some intriguing and noteworthy results that clearly distinguish between even and odd-numbered solar cycles.The study suggests that the Sun behaves differently in odd and even-numbered solar cycles as it comes from the massive solar eruptions.During even-numbered solar cycles,variations with a period of∼44 days are prominently observed in addition to solar rotation(∼27 days)and extended solar(∼36 days)rotation.However,in addition to solar rotation,prolonged solar rotation,and periods of around 44 days,we also detect a number of intermittent changes with nearly comparable amplitude during the oddnumbered solar cycles.The findings also demonstrate that,in contrast to odd-numbered solar cycles,the emissions rate of these disruptions is more distinct and predictable during even-numbered solar cycles.展开更多
During the total solar eclipse of 2013 November 3, a fiber-based spectrometer captured the flash spectrum within the wavelength range of 5162–5325Å, with the field-of-view positioned approximately 0.04 R⊙above ...During the total solar eclipse of 2013 November 3, a fiber-based spectrometer captured the flash spectrum within the wavelength range of 5162–5325Å, with the field-of-view positioned approximately 0.04 R⊙above the east limb, near the second-contact point. This placement near the innermost corona, together with the nearby Baily's beads, enabled the detection of emission lines from the photosphere, lower chromosphere, and corona in the same spectral frame. The higher field-of-view made the coronal line Fe XIV 5303Åmore visible, while the reduced intensity of photospheric and lower chromospheric light, caused by terrestrial scattering, also influenced the observed spectrum. Meanwhile, we selected 18 flash emission lines to measure the ratio of the relative line height of the flash emission line to the relative line depth of the corresponding solar absorption line. This ratio serves as a diagnostic of the source function, minimizing opacity effects. Comparison of disk and flash spectra shows that this ratio increases for spectral lines at greater formation heights, being strongest for chromospheric lines(particularly Fe II), moderate for photospheric low-FIP lines, and weakest for photospheric neutral lines. This trend suggests a rising source function with formation height, potentially linked to increasing electron temperatures or influenced by factors observed in flash spectra near active regions as reported in earlier studies.展开更多
This study analyzes the evolution and dynamics of intensity oscillations in coronal sunspots and their surroundings using multi-wavelength image data from the Atmospheric Imaging Assembly(AIA)and Helioseismic and Magn...This study analyzes the evolution and dynamics of intensity oscillations in coronal sunspots and their surroundings using multi-wavelength image data from the Atmospheric Imaging Assembly(AIA)and Helioseismic and Magnetic Imager(HMI)on board the Solar Dynamics Observatory(SDO).Intensity time series were extracted and analyzed from consecutive macropixels along thin coronal loop paths originating in a quiet sunspot.Fourier and wavelet analyses of corrected intensity time series reveal dominant 3 and 5 minute oscillations.Signals were filtered using the Fourier and inverse transforms to isolate narrow bands around the dominant oscillation periods.Diagrams and time-distance maps of intensity time series were plotted for Fourierfiltered AIA 131A,171A,193A,and 211A channels,along with SDO/HMI magnetograms and dopplergrams at 6173A.The plots clearly show propagating oscillations with amplitude modulation(AM)across all macropixels along selected coronal paths in nearly all AIA and HMI channels.The phase speeds of the filtered oscillations,measured via slope calculations in time-distance maps,indicate that the intensity disturbances are slow magneto-acoustic waves.These results suggest that AM likely arises from the superposition of counterpropagating waves with slightly different frequencies(beta-like phenomena)due to Doppler shifts from background plasma flow along loop paths.Validating this hypothesis could establish AM's significance in solar coronal seismology for determining background plasma flow speed,the source of long-period oscillations,and coronal plasma heating mechanisms.展开更多
Magnetic reconnection driving a two-sided-loop jet is typically associated with interactions between an emerging bipole and the overlying horizontal magnetic field,or between filaments from separate magnetic systems.L...Magnetic reconnection driving a two-sided-loop jet is typically associated with interactions between an emerging bipole and the overlying horizontal magnetic field,or between filaments from separate magnetic systems.Leveraging high temporal and spatial resolution observations from ground-based and space-borne instruments,we have identified a two-sided-loop jet originating from magnetic reconnection between threads within a single filament.Our observations show that as two initially crossing filamentary threads within the filament converge,reconnection takes place at their intersection.In the Doppler images,distinct redshift and blueshift signals are observed at the locations where the filament threads intersected.This process generates a two-sided-loop jet with outflow speeds of 22.2 and 62.5 km s^(-1).Following reconnection,the original crossing threads transform into two parallel threads that subsequently separate at speeds of 2.8 and 8.3kms^(-1).This observation offers a new perspective on the mechanisms responsible for jet formation.展开更多
We examined the heliolatitude distribution and North-South(N-S)asymmetry of Ground Level Enhancement(GLE)event source locations from 1942 to 2024,finding distinct patterns between the periods 1942–1979 and1980–2024....We examined the heliolatitude distribution and North-South(N-S)asymmetry of Ground Level Enhancement(GLE)event source locations from 1942 to 2024,finding distinct patterns between the periods 1942–1979 and1980–2024.Between 1942 and 1979,33 GLE events were recorded:5 from the southern hemisphere within[S3,S11]and 28 from the northern hemisphere within[N7,N37].The southeast quadrant was devoid of any source locations for GLE events.45.4%of the source locations of the GLE events were within the latitudinal range of[S15,N15].The remaining source locations of the GLE events were distributed at latitudes above 15°in the northern hemisphere.Between 1980 and 2024,43 GLE events were recorded:25 from the southern hemisphere and 18 from the northern hemisphere,with all events above 30°latitude originating from the northern hemisphere.Approximately 44.2%of the source locations of the GLE events were distributed within the latitudinal band[S15,N15].Over the period from 1942 to 2024,44.7%within[S15,N15],63.2%within[S20,N20],80.3%within[S25,N25],88.2%within[S30,N30],and 11.8%at latitudes above 30°.N-S asymmetry was significant at latitudes above 0°,5°,10°,15°,20°and 30°,with northern hemisphere dominance.Moreover,a strong inverse correlation exists between the number of GLE events from the northern and southern hemispheres at latitudes above 0°,5°,10°,15°,20°,25°and 30°.展开更多
In winter,the weather is usually cold and everything seems a bit dull.Butthe sun in winter is special.When the sun shines brightly in the clear blue sky,it brings warm(1)to thecold world.The golden sunlight spreads he...In winter,the weather is usually cold and everything seems a bit dull.Butthe sun in winter is special.When the sun shines brightly in the clear blue sky,it brings warm(1)to thecold world.The golden sunlight spreads here and there and it makes the whitesnow shine like diamonds.Although the trees are usually bare in winter,but(2)they look beautiful with the sunlight falling on them.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)12333010the National Key R&D Program of China 2022YFF0503002+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(grant No.XDB0560000)the NSFC 11921003supported by the Prominent Postdoctoral Project of Jiangsu Province(2023ZB304)supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences,grant No.XDA15320000.
文摘Indirect X-ray modulation imaging has been adopted in a number of solar missions and provided reconstructed X-ray images of solar flares that are of great scientific importance.However,the assessment of the image quality of the reconstruction is still difficult,which is particularly useful for scheme design of X-ray imaging systems,testing and improvement of imaging algorithms,and scientific research of X-ray sources.Currently,there is no specified method to quantitatively evaluate the quality of X-ray image reconstruction and the point-spread function(PSF)of an X-ray imager.In this paper,we propose percentage proximity degree(PPD)by considering the imaging characteristics of X-ray image reconstruction and in particular,sidelobes and their effects on imaging quality.After testing a variety of imaging quality assessments in six aspects,we utilized the technique for order preference by similarity to ideal solution to the indices that meet the requirements.Then we develop the final quality index for X-ray image reconstruction,QuIX,which consists of the selected indices and the new PPD.QuIX performs well in a series of tests,including assessment of instrument PSF and simulation tests under different grid configurations,as well as imaging tests with RHESSI data.It is also a useful tool for testing of imaging algorithms,and determination of imaging parameters for both RHESSI and ASO-S/Hard X-ray Imager,such as field of view,beam width factor,and detector selection.
基金supported by the National Natural Science Foundation of China(NSFC)under grant No.12233012,the Strategic Priority Research Program of the Chinese Academy of Sciences,grant No.XDB0560102the National Key R&D Program of China 2022YFF0503003(2022YFF0503000)。
文摘The in-flight calibration and performance of the Solar Disk Imager(SDI),which is a pivotal instrument of the LyαSolar Telescope onboard the Advanced Space-based Solar Observatory mission,suggested a much lower spatial resolution than expected.In this paper,we developed the SDI point-spread function(PSF)and Image Bivariate Optimization Algorithm(SPIBOA)to improve the quality of SDI images.The bivariate optimization method smartly combines deep learning with optical system modeling.Despite the lack of information about the real image taken by SDI and the optical system function,this algorithm effectively estimates the PSF of the SDI imaging system directly from a large sample of observational data.We use the estimated PSF to conduct deconvolution correction to observed SDI images,and the resulting images show that the spatial resolution after correction has increased by a factor of more than three with respect to the observed ones.Meanwhile,our method also significantly reduces the inherent noise in the observed SDI images.The SPIBOA has now been successfully integrated into the routine SDI data processing,providing important support for the scientific studies based on the data.The development and application of SPIBOA also paves new ways to identify astronomical telescope systems and enhance observational image quality.Some essential factors and precautions in applying the SPIBOA method are also discussed.
基金supported by the Strategic Priority Research Program on Space Science,Chinese Academy of Sciencessupported by the National Key R&D Program of China 2022YFF0503003(2022YFF0503000),2021YFA1600500 (2021YFA1600502)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences,grant No.XDB0560000the National Natural Science Foundation of China (NSFC,grant Nos.12373065,12203102,12403064,and 12403068)Natural Science Foundation of Jiangsu Province (BK20231510,BK20241707)Supported by the Specialized Research Fund for State Key Laboratories,and Yunnan Key Laboratory of Solar Physics and Space Science under the grant No.YNSPCC202206
文摘In this paper,we perform a follow-up investigation of the solar eruption originating from active region 13575 on 2024 February 9.The primary eruption of a hot channel generates an X3.4 class flare,a full-halo coronal mass ejection(CME),and an extreme-ultraviolet(EUV)wave.Interaction between the wave and a quiescent prominence(QP)leads to a large-amplitude,transverse oscillation of QP.After the transverse oscillation,QP loses equilibrium and rises up.The ascending motion of the prominence is coherently detected and tracked up to∼1.68 R_(⊙)by the Solar UltraViolet Imager onboard the GOES-16 spacecraft and up to∼2.2 R_(⊙)by the Solar Corona Imager(SCI_UV)of the LyαSolar Telescope onboard the ASO-S spacecraft.The velocity increases linearly from 12.3 to 68.5 km s^(−1)at 18:30 UT.The sympathetic eruption of QP drives the second CME with a typical three-part structure.The bright core comes from the eruptive prominence,which could be further observed up to∼3.3 R_(⊙) by the Large Angle Spectroscopic Coronagraph onboard the Solar and Heliospheric Observatory mission.The leading edge of the second CME accelerates continuously from∼120 to∼277 km s^(−1).The EUV wave plays an important role in linking the primary eruption with the sympathetic eruption.
文摘The magnetic fields and dynamical processes in the solar polar regions play a crucial role in the solar magnetic cycle and in supplying mass and energy to the fast solar wind,ultimately being vital in controlling solar activities and driving space weather.Despite numerous efforts to explore these regions,to date no imaging observations of the Sun's poles have been achieved from vantage points out of the ecliptic plane,leaving their behavior and evolution poorly understood.This observation gap has left three top-level scientific questions unanswered:How does the solar dynamo work and drive the solar magnetic cycle?What drives the fast solar wind?How do space weather processes globally originate from the Sun and propagate throughout the solar system?The Solar Polarorbit Observatory(SPO)mission,a solar polar exploration spacecraft,is proposed to address these three unanswered scientific questions by imaging the Sun's poles from high heliolatitudes.In order to achieve its scientific goals,SPO will carry six remote-sensing and four in-situ instruments to measure the vector magnetic fields and Doppler velocity fields in the photosphere,to observe the Sun in the extreme ultraviolet,X-ray,and radio wavelengths,to image the corona and the heliosphere up to 45 R_(s),and to perform in-situ detection of magnetic fields,and low-and high-energy particles in the solar wind.The SPO mission is capable of providing critical vector magnetic fields and Doppler velocities of the polar regions to advance our understanding of the origin of the solar magnetic cycle,providing unprecedented imaging observations of the solar poles alongside in-situ measurements of charged particles and magnetic fields from high heliolatitudes to unveil the mass and energy supply that drive the fast solar wind,and providing observational constraints for improving our ability to model and predict the three-dimensional(3D)structures and propagation of space weather events.
基金supported by the National Key R&D Program of China No.2022YFF0503800the Strategic Priority Research Program of the Chinese Academy of Sciences(grant Nos.XDA17040507 and XDB0560000)+1 种基金NSFC grant 11933009the Yunnan Province Scientist Workshop of Solar Physics,the Yunnan Key Laboratory of Solar Physics and Space Science(202205AG070009)。
文摘A 50 mm balloon-borne white-light coronagraph(BBWLC)to observe white-light solar corona over the altitude range from 1.08 R_(⊙)to 1.50 R_(⊙)has recently been indigenously developed by Yunnan Observatories in collaboration with Shandong University(in Weihai)and Changchun Institute of Optics,Fine Mechanics and Physics,which will significantly improve the ability of China to detect and measure the inner corona.On 2022 October 4,its first scientific flight took place at the Dachaidan area in Qinghai province of China.We briefly describe the BBWLC mission including its optical design,mechanical structure,pointing system,the first flight and results associated with the data processing approach.Preliminary analysis of the data shows that BBWLC imaged the K-corona with three streamer structures on the west limb of the Sun.To further confirm the coronal signals obtained by BBWLC,comparisons were made with observations of the K-coronagraph of the High Altitude Observatory and the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory.We conclude that BBWLC eventually observed the white-light corona in its first scientific flight.
基金supported by the National Key Research and Development Program of China(grant No.2022YFF0503600)the National Natural Science Foundation of China(NSFC,grant No.42130202).
文摘Solar flares are one of the strongest outbursts of solar activity,posing a serious threat to Earth’s critical infrastructure,such as communications,navigation,power,and aviation.Therefore,it is essential to accurately predict solar flares in order to ensure the safety of human activities.Currently,the research focuses on two directions:first,identifying predictors with more physical information and higher prediction accuracy,and second,building flare prediction models that can effectively handle complex observational data.In terms of flare observability and predictability,this paper analyses multiple dimensions of solar flare observability and evaluates the potential of observational parameters in prediction.In flare prediction models,the paper focuses on data-driven models and physical models,with an emphasis on the advantages of deep learning techniques in dealing with complex and high-dimensional data.By reviewing existing traditional machine learning,deep learning,and fusion methods,the key roles of these techniques in improving prediction accuracy and efficiency are revealed.Regarding prevailing challenges,this study discusses the main challenges currently faced in solar flare prediction,such as the complexity of flare samples,the multimodality of observational data,and the interpretability of models.The conclusion summarizes these findings and proposes future research directions and potential technology advancement.
文摘Major solar plasma disturbances are subjected to Lomb-Scargle periodogram and wavelet analysis to determine the occurrence frequency.These disruptions include interplanetary coronal mass ejection,sudden storm commencement,high-speed streams,corotating interaction regions,interplanetary shocks and Forbush decreases.We included information on all of the aforementioned solar disturbances for the last six solar cycles,from 1965 to 2023,for this study.Our findings reveal some intriguing and noteworthy results that clearly distinguish between even and odd-numbered solar cycles.The study suggests that the Sun behaves differently in odd and even-numbered solar cycles as it comes from the massive solar eruptions.During even-numbered solar cycles,variations with a period of∼44 days are prominently observed in addition to solar rotation(∼27 days)and extended solar(∼36 days)rotation.However,in addition to solar rotation,prolonged solar rotation,and periods of around 44 days,we also detect a number of intermittent changes with nearly comparable amplitude during the oddnumbered solar cycles.The findings also demonstrate that,in contrast to odd-numbered solar cycles,the emissions rate of these disruptions is more distinct and predictable during even-numbered solar cycles.
基金supported by the National Natural Science Foundation of China(NSFC)under grant Nos.12473054 and 12127901the Strategic Priority Research Program of the Chinese Academy of Sciences under grant No.XDB0560000+1 种基金Yunnan Key Laboratory of Solar Physics and Space Science under No.202205AG070009Yunnan Fundamental Research Projects under No.202105AC160085.
文摘During the total solar eclipse of 2013 November 3, a fiber-based spectrometer captured the flash spectrum within the wavelength range of 5162–5325Å, with the field-of-view positioned approximately 0.04 R⊙above the east limb, near the second-contact point. This placement near the innermost corona, together with the nearby Baily's beads, enabled the detection of emission lines from the photosphere, lower chromosphere, and corona in the same spectral frame. The higher field-of-view made the coronal line Fe XIV 5303Åmore visible, while the reduced intensity of photospheric and lower chromospheric light, caused by terrestrial scattering, also influenced the observed spectrum. Meanwhile, we selected 18 flash emission lines to measure the ratio of the relative line height of the flash emission line to the relative line depth of the corresponding solar absorption line. This ratio serves as a diagnostic of the source function, minimizing opacity effects. Comparison of disk and flash spectra shows that this ratio increases for spectral lines at greater formation heights, being strongest for chromospheric lines(particularly Fe II), moderate for photospheric low-FIP lines, and weakest for photospheric neutral lines. This trend suggests a rising source function with formation height, potentially linked to increasing electron temperatures or influenced by factors observed in flash spectra near active regions as reported in earlier studies.
文摘This study analyzes the evolution and dynamics of intensity oscillations in coronal sunspots and their surroundings using multi-wavelength image data from the Atmospheric Imaging Assembly(AIA)and Helioseismic and Magnetic Imager(HMI)on board the Solar Dynamics Observatory(SDO).Intensity time series were extracted and analyzed from consecutive macropixels along thin coronal loop paths originating in a quiet sunspot.Fourier and wavelet analyses of corrected intensity time series reveal dominant 3 and 5 minute oscillations.Signals were filtered using the Fourier and inverse transforms to isolate narrow bands around the dominant oscillation periods.Diagrams and time-distance maps of intensity time series were plotted for Fourierfiltered AIA 131A,171A,193A,and 211A channels,along with SDO/HMI magnetograms and dopplergrams at 6173A.The plots clearly show propagating oscillations with amplitude modulation(AM)across all macropixels along selected coronal paths in nearly all AIA and HMI channels.The phase speeds of the filtered oscillations,measured via slope calculations in time-distance maps,indicate that the intensity disturbances are slow magneto-acoustic waves.These results suggest that AM likely arises from the superposition of counterpropagating waves with slightly different frequencies(beta-like phenomena)due to Doppler shifts from background plasma flow along loop paths.Validating this hypothesis could establish AM's significance in solar coronal seismology for determining background plasma flow speed,the source of long-period oscillations,and coronal plasma heating mechanisms.
基金supported by the National Natural Science Foundation of China(NSFC,grant Nos.12303062 and 12203043)the Sichuan Science and Technology Program(2023NSFSC1351,2025ZNSFSC0315)+1 种基金Key Laboratory of Detection and Application of Space Effect in Southwest Sichuan at Leshan Normal University,Education Department of Sichuan Province(No.ZDXM20241002)Project Supported by the Specialized Research Fund for State Key Laboratory of Solar Activity and Space Weather。
文摘Magnetic reconnection driving a two-sided-loop jet is typically associated with interactions between an emerging bipole and the overlying horizontal magnetic field,or between filaments from separate magnetic systems.Leveraging high temporal and spatial resolution observations from ground-based and space-borne instruments,we have identified a two-sided-loop jet originating from magnetic reconnection between threads within a single filament.Our observations show that as two initially crossing filamentary threads within the filament converge,reconnection takes place at their intersection.In the Doppler images,distinct redshift and blueshift signals are observed at the locations where the filament threads intersected.This process generates a two-sided-loop jet with outflow speeds of 22.2 and 62.5 km s^(-1).Following reconnection,the original crossing threads transform into two parallel threads that subsequently separate at speeds of 2.8 and 8.3kms^(-1).This observation offers a new perspective on the mechanisms responsible for jet formation.
基金supported by the National Natural Science Foundation of China(grant Nos.42374092,41074132,41274193,41474166,41774195,and 41874187)the Special Fund of the Institute of Geophysics,China Earthquake Administration(Grant Number DQJB22X12)。
文摘We examined the heliolatitude distribution and North-South(N-S)asymmetry of Ground Level Enhancement(GLE)event source locations from 1942 to 2024,finding distinct patterns between the periods 1942–1979 and1980–2024.Between 1942 and 1979,33 GLE events were recorded:5 from the southern hemisphere within[S3,S11]and 28 from the northern hemisphere within[N7,N37].The southeast quadrant was devoid of any source locations for GLE events.45.4%of the source locations of the GLE events were within the latitudinal range of[S15,N15].The remaining source locations of the GLE events were distributed at latitudes above 15°in the northern hemisphere.Between 1980 and 2024,43 GLE events were recorded:25 from the southern hemisphere and 18 from the northern hemisphere,with all events above 30°latitude originating from the northern hemisphere.Approximately 44.2%of the source locations of the GLE events were distributed within the latitudinal band[S15,N15].Over the period from 1942 to 2024,44.7%within[S15,N15],63.2%within[S20,N20],80.3%within[S25,N25],88.2%within[S30,N30],and 11.8%at latitudes above 30°.N-S asymmetry was significant at latitudes above 0°,5°,10°,15°,20°and 30°,with northern hemisphere dominance.Moreover,a strong inverse correlation exists between the number of GLE events from the northern and southern hemispheres at latitudes above 0°,5°,10°,15°,20°,25°and 30°.
文摘In winter,the weather is usually cold and everything seems a bit dull.Butthe sun in winter is special.When the sun shines brightly in the clear blue sky,it brings warm(1)to thecold world.The golden sunlight spreads here and there and it makes the whitesnow shine like diamonds.Although the trees are usually bare in winter,but(2)they look beautiful with the sunlight falling on them.
