In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relat...In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.展开更多
The scattered stray light of a coronagraph is a type of stray light that is generated by the objective lens as its surface defects are irradiated by sunlight.The defects mainly include dust and blemishes on the lens s...The scattered stray light of a coronagraph is a type of stray light that is generated by the objective lens as its surface defects are irradiated by sunlight.The defects mainly include dust and blemishes on the lens surface,microroughness of the lens surface,and impurity and inhomogeneity of the glass.Unlike the other types of relatively stable defects introduced when the objective lens is being manufactured,the scattered stray light caused by dusts on the lens surface is difficult to quantify accurately due to the disorder and randomness of the dust accumulation.The contribution of this type of stray light to the overall stray light level is difficult to determine through simulations and experiments.This can result in continuous deterioration of the stray light level of a coronagraph and thus affect the observation capabilities of the instrument.To solve this issue,through analyzing the forming mechanism of scattered stray light and ghost image generated by the inner-occulted coronagraph,we propose a novel method to monitor the scattered stray light from dusts by utilizing different stray light correlation coefficients.In this method,we first simulate and measure the level of stray light from the ghost image of the objective lens,and then determine the flux ratio of scattered light and ghost image on the conjugate plane.Although the flux ratio varies with the accumulation of dusts on the lens surface,it remains constant on the image plane.Therefore,the level of dust scattering light on the image plane can be obtained by using this ratio together with the level of ghost image stray light.The accuracy of this method has been validated in a laboratory by applying the objective lens with numerous surface cleanliness levels.展开更多
In this study,we explore the elongated granulations and stretched dark lanes within the emerging anti-Hale active region NOAA AR 12720.Utilizing high-resolution observations from the New Vacuum Solar Telescope,we disc...In this study,we explore the elongated granulations and stretched dark lanes within the emerging anti-Hale active region NOAA AR 12720.Utilizing high-resolution observations from the New Vacuum Solar Telescope,we discern a prevalence of elongated granules and stretched dark lanes associated with the emergence of new magnetic flux positioned between two primary opposing magnetic polarities.These elongated granulations and stretched dark lanes exhibit an alignment of strong transverse fields and a significant inclination angle.The endpoints of these features separate from each other,with their midpoints predominantly characterized by blueshifted signals in the photosphere.This suggests a close association between elongated granules and stretched dark lanes with the newly emerging flux.Additionally,we find that the stretched dark lanes display a more pronounced correlation with strong blueshifts and photospheric transverse magnetic fields compared to the elongated granulations.The transverse magnetic field within these stretched dark lanes reaches magnitudes of approximately 300-400 G,and the inclination angle demonstrates an“arch-like”pattern along the trajectory of the stretched dark lane.Based on these observed characteristics,we infer the presence of an emerging flux tube with an“arch-like”shape situated along the stretched dark lane.Consequently,we conclude that the stretched dark lanes likely represent manifestations of the emerging flux tube,while the elongated granulations may correspond to the gaps between the emerging flux tubes.展开更多
The radioheliograph is an extensive array of antennas operating on the principle of aperture synthesis to produce images of the Sun.The image acquired by the telescope results from convoluting the Sun’s true brightne...The radioheliograph is an extensive array of antennas operating on the principle of aperture synthesis to produce images of the Sun.The image acquired by the telescope results from convoluting the Sun’s true brightness distribution with the antenna array’s directional pattern.The imaging quality of the radioheliograph is affected by a multitude of factors,with the performance of the“dirty beam”being simply one component.Other factors such as imaging methods,calibration techniques,clean algorithms,and more also play a significant influence on the resulting image quality.As the layout of the antenna array directly affects the performance of the dirty beam,the design of an appropriate antenna configuration is critical to improving the imaging quality of the radioheliograph.Based on the actual needs of observing the Sun,this work optimized the antenna array design and proposed a twodimensional low-redundancy array.The proposed array was compared with common T-shaped arrays,Y-shaped arrays,uniformly spaced circular arrays,and three-arm spiral arrays.Through simulations and experiments,their performance in terms of sampling point numbers,UV coverage area,beam-half width,sidelobe level,and performance in the absence of antennas are compared and analyzed.It was found that each of these arrays has its advantages,but the two-dimensional low-redundancy array proposed in this paper performs best in overall evaluation.It has the shortest imaging calculation time among the array types and is highly robust when antennas are missing,making it the most suitable choice.展开更多
The Educational Adaptive-optics Solar Telescope(EAST)at the Shanghai Astronomy Museum has been running routine astronomical observations since 2021.It is a 65-cm-aperture Gregorian solar telescope for scientific educa...The Educational Adaptive-optics Solar Telescope(EAST)at the Shanghai Astronomy Museum has been running routine astronomical observations since 2021.It is a 65-cm-aperture Gregorian solar telescope for scientific education,outreach,and research.The telescope system is designed in an“open”format so that the solar tower architecture can be integrated with it,and visitors can watch the observations live from inside the tower.Equipped with adaptive optics,a high-resolution imaging system,and an integral field unit spectro-imaging system,this telescope can obtain high-resolution solar images in the TiO and Hαbands,and perform spectral image reconstruction using 400 optical fibers at selected wavelengths.It can be used not only in public education and scientific outreach but also in solar physics research.展开更多
The primary mirrors of current and future large telescopes always employ a segmented mirror configuration.The small but non-negligible gaps between neighboring segments cause additional diffraction,which restricts the...The primary mirrors of current and future large telescopes always employ a segmented mirror configuration.The small but non-negligible gaps between neighboring segments cause additional diffraction,which restricts the performance of high-contrast coronagraph.To solve this problem,we propose a coronagraph system based on a single liquid crystal spatial light modulator(SLM).This spatial light modulator is used for amplitude apodization,and its feasibility and potential performance are demonstrated using a laboratory setup using the stochastic parallel gradient descent(SPGD)algorithm to control the spatial light modulator,which is based on point spread function(PSF)sensing and evaluation and optimized for maximum contrast in the discovery working area as a merit function.The system delivers a contrast in the order of 10−6,and shows excellent potential to be used in current and future large aperture telescopes,both on the ground and in space.展开更多
文摘In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.
基金supported by the National Key R&D Program of China No.2021YFA0718600the National Natural Science Foundation of China(grant Nos.41904168,42274227 and U1931122)the Chinese Meridian Project。
文摘The scattered stray light of a coronagraph is a type of stray light that is generated by the objective lens as its surface defects are irradiated by sunlight.The defects mainly include dust and blemishes on the lens surface,microroughness of the lens surface,and impurity and inhomogeneity of the glass.Unlike the other types of relatively stable defects introduced when the objective lens is being manufactured,the scattered stray light caused by dusts on the lens surface is difficult to quantify accurately due to the disorder and randomness of the dust accumulation.The contribution of this type of stray light to the overall stray light level is difficult to determine through simulations and experiments.This can result in continuous deterioration of the stray light level of a coronagraph and thus affect the observation capabilities of the instrument.To solve this issue,through analyzing the forming mechanism of scattered stray light and ghost image generated by the inner-occulted coronagraph,we propose a novel method to monitor the scattered stray light from dusts by utilizing different stray light correlation coefficients.In this method,we first simulate and measure the level of stray light from the ghost image of the objective lens,and then determine the flux ratio of scattered light and ghost image on the conjugate plane.Although the flux ratio varies with the accumulation of dusts on the lens surface,it remains constant on the image plane.Therefore,the level of dust scattering light on the image plane can be obtained by using this ratio together with the level of ghost image stray light.The accuracy of this method has been validated in a laboratory by applying the objective lens with numerous surface cleanliness levels.
基金supported by the National Key R&D Program of China(2019YFA0405000)the Strategic Priority Research Program of the Chinese Academy of Sciences,grant No.XDB0560000+4 种基金the National Natural Science Foundation of China(NSFC,Grant Nos.12473059,12003064,12325303,11973084,12203020,12203097,12273110,and 12003068)the Yunnan Key Laboratory of Solar Physics and Space Science(202205AG070009)the Yunnan Science Foundation of China under Nos.202301AT070347,202201AT070194,202001AU070077Yunnan Science Foundation for Distinguished Young Scholars No.202001AV070004the grant associated with a project of the Group for Innovation of Yunnan province。
文摘In this study,we explore the elongated granulations and stretched dark lanes within the emerging anti-Hale active region NOAA AR 12720.Utilizing high-resolution observations from the New Vacuum Solar Telescope,we discern a prevalence of elongated granules and stretched dark lanes associated with the emergence of new magnetic flux positioned between two primary opposing magnetic polarities.These elongated granulations and stretched dark lanes exhibit an alignment of strong transverse fields and a significant inclination angle.The endpoints of these features separate from each other,with their midpoints predominantly characterized by blueshifted signals in the photosphere.This suggests a close association between elongated granules and stretched dark lanes with the newly emerging flux.Additionally,we find that the stretched dark lanes display a more pronounced correlation with strong blueshifts and photospheric transverse magnetic fields compared to the elongated granulations.The transverse magnetic field within these stretched dark lanes reaches magnitudes of approximately 300-400 G,and the inclination angle demonstrates an“arch-like”pattern along the trajectory of the stretched dark lane.Based on these observed characteristics,we infer the presence of an emerging flux tube with an“arch-like”shape situated along the stretched dark lane.Consequently,we conclude that the stretched dark lanes likely represent manifestations of the emerging flux tube,while the elongated granulations may correspond to the gaps between the emerging flux tubes.
基金supported by the grants of the National Natural Science Foundation of China(42127804,42374219)。
文摘The radioheliograph is an extensive array of antennas operating on the principle of aperture synthesis to produce images of the Sun.The image acquired by the telescope results from convoluting the Sun’s true brightness distribution with the antenna array’s directional pattern.The imaging quality of the radioheliograph is affected by a multitude of factors,with the performance of the“dirty beam”being simply one component.Other factors such as imaging methods,calibration techniques,clean algorithms,and more also play a significant influence on the resulting image quality.As the layout of the antenna array directly affects the performance of the dirty beam,the design of an appropriate antenna configuration is critical to improving the imaging quality of the radioheliograph.Based on the actual needs of observing the Sun,this work optimized the antenna array design and proposed a twodimensional low-redundancy array.The proposed array was compared with common T-shaped arrays,Y-shaped arrays,uniformly spaced circular arrays,and three-arm spiral arrays.Through simulations and experiments,their performance in terms of sampling point numbers,UV coverage area,beam-half width,sidelobe level,and performance in the absence of antennas are compared and analyzed.It was found that each of these arrays has its advantages,but the two-dimensional low-redundancy array proposed in this paper performs best in overall evaluation.It has the shortest imaging calculation time among the array types and is highly robust when antennas are missing,making it the most suitable choice.
基金supported by the Shanghai Municipal People’s Government
文摘The Educational Adaptive-optics Solar Telescope(EAST)at the Shanghai Astronomy Museum has been running routine astronomical observations since 2021.It is a 65-cm-aperture Gregorian solar telescope for scientific education,outreach,and research.The telescope system is designed in an“open”format so that the solar tower architecture can be integrated with it,and visitors can watch the observations live from inside the tower.Equipped with adaptive optics,a high-resolution imaging system,and an integral field unit spectro-imaging system,this telescope can obtain high-resolution solar images in the TiO and Hαbands,and perform spectral image reconstruction using 400 optical fibers at selected wavelengths.It can be used not only in public education and scientific outreach but also in solar physics research.
基金supported by the National Natural Science Foundation of China (U2031210 and 11827804)Science Research from the China Manned Space Project (CMS-CSST-2021-A11 and CMS-CSST-2021-B04).
文摘The primary mirrors of current and future large telescopes always employ a segmented mirror configuration.The small but non-negligible gaps between neighboring segments cause additional diffraction,which restricts the performance of high-contrast coronagraph.To solve this problem,we propose a coronagraph system based on a single liquid crystal spatial light modulator(SLM).This spatial light modulator is used for amplitude apodization,and its feasibility and potential performance are demonstrated using a laboratory setup using the stochastic parallel gradient descent(SPGD)algorithm to control the spatial light modulator,which is based on point spread function(PSF)sensing and evaluation and optimized for maximum contrast in the discovery working area as a merit function.The system delivers a contrast in the order of 10−6,and shows excellent potential to be used in current and future large aperture telescopes,both on the ground and in space.
