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Are solar Active Regions Born with Neutralized Currents?

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Research in Astronomy and Astrophysics 2024年第7期24卷 82-91页

作者： Aiying Duan Yaoyu Xing Chaowei Jiang Planetary Environmental and Astrobiological Research laboratory (PEARL) School of Atmospheric SciencesSun Yat-sen University yunnan key laboratory of the solar physics and space science key laboratory of Tropical Atmosphere-Ocean System Sun Yat-sen UniversityMinistry of Education Institute of space science and Applied Technology Harbin Institute of Technology

solar active regions(ARs) are formed by the emergence of current-carrying magnetic flux tubes from below the photosphere. Although for an isolated flux tube the direct and return currents flowing along the tube should balance with each other, it remains controversial whether such a neutralization of currents is also maintained during the emergence process. Here we present a systematic survey of the degrees of the current neutralization in a large sample of flux-emerging ARs which appeared on the solar disk around the central meridian from 2010 to *** vector magnetograms taken by Helioseismic and Magnetic Imager onboard solar Dynamic Observatory are employed to calculate the distributions of the vertical current density at the photosphere. Focusing on the main phase of flux emergence, i.e., the phase in which the total unsigned magnetic flux is continuously increased, we statistically examined the ratios of direct to return currents in all the ARs. Such a large-sample statistical study suggests that most of the ARs were born with currents close to neutralization. The degree of current neutralization seems to be not affected by the active-region size, the active-region growing rate, and the total unsigned *** only correlation of significance as found is that the stronger the magnetic field nonpotentiality is, the further the AR deviates from current neutrality, which supports previous event studies that eruption-productive ARs often have non-neutralized currents.

关键词： Sun: corona Sun: coronal mass ejections (CMEs) Sun: flares Sun: magnetic fields

Resolution Enhancement of SOHO/MDI Magnetograms

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Research in Astronomy and Astrophysics 2024年第6期24卷 358-367页

作者： Ying Qin Kai-Fan Ji Hui Liu Xiao-Guang Yu yunnan Observatories Chinese Academy of SciencesKunming 650011China University of Chinese Academy of sciences Beijing 100049China yunnan key laboratory of solar physics and space science Kunming 650216China key laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China

Research on the solar magnetic field and its effects on solar dynamo mechanisms and space weather events has benefited from the continual improvements in instrument resolution and measurement *** augmentation and assimilation of historical observational data timelines also play a significant role in understanding the patterns of solar magnetic field *** the realm of astronomical data processing,super-resolution(SR)reconstruction refers to the process of using a substantial corpus of training data to learn the nonlinear mapping between low-resolution(LR)and high-resolution(HR)images,thereby achieving higherresolution astronomical *** paper is an application study in high-dimensional nonlinear *** learning models were employed to perform SR modeling on SOHO/MDI magnetograms and SDO/HMI magnetograms,thus reliably achieving resolution enhancement of full-disk SOHO/MDI magnetograms and enhancing the image resolution to obtain more detailed *** this study,a data set comprising 9717pairs of data from 2010 April to 2011 February was used as the training set,1332 pairs from 2011 March were used as the validation set and 1034 pairs from 2011 April were used as the test *** data preprocessing,we randomly cropped 128×128 sub-images as the LR cases from the full-disk MDI magnetograms,and the corresponding 512×512 sub-images as HR ones from the HMI full-disk magnetograms for model *** tests conducted have shown that the study successfully produced reliable 4×SR reconstruction of full-disk MDI *** MESR model's results(0.911)were highly correlated with the target HMI magnetographs as indicated by the correlation coefficient ***,the method achieved the best PSNR,SSIM,MAE and RMSE values,indicating that the MESR model can effectively reconstruct magnetograms.

关键词： magnetic fields techniques:image processing virtual observatory tools Sun:magnetic fields

Simultaneous detection of flare-associated kink oscillations and extreme-ultraviolet waves

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science China(Technological sciences) 2024年第5期67卷 1592-1601页

作者： LI Dong HOU ZhenYong BAI XianYong LI Chuan FANG Matthew ZHAO HaiSheng WANG JinCheng NING ZongJun key laboratory of Dark Matter and space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing210023China yunnan key laboratory of the solar physics and space science Kunming650216China School of Earth and space sciences Peking UniversityBeijing100871China National Astronomical Observatories Chinese Academy of SciencesBeijing100101China School of Astronomy and space science University of Chinese Academy of SciencesBeijing100049China School of Astronomy and space science Nanjing UniversityNanjing210023China key laboratory of Modern Astronomy and Astrophysics Ministry of EducationNanjing UniversityNanjing210023China Columbus Academy GahannaOhio43230USA key laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China yunnan Observatories Chinese Academy of SciencesKunming650216China

Kink oscillations,which are frequently observed in coronal loops and prominences,are often accompanied by extreme-ultraviolet(EUV)***,much more needs to be explored regarding the causal relationships between kink oscillations and EUV *** this article,we report the simultaneous detection of kink oscillations and EUV waves that are both associated with an X2.1 flare on 2023 March 03(SOL2023-03-03T17:39).The kink oscillations,which are almost perpendicular to the axes of loop-like structures,are observed in three coronal loops and one *** short loop shows in-phase oscillation within the same period of 5.2 min at three *** oscillation could be triggered by the pushing of an expanding loop and interpreted as the standing kink *** lags are found between the kink oscillations of the short loop and two long loops,suggesting that the kink wave travels in different *** kink oscillations of one long loop and the prominence are possibly driven by the disturbance of the coronal mass ejection(CME),and that of another long loop might be attributed to the interaction of the EUV *** onset time of the kink oscillation of the short loop is nearly same as the beginning of an EUV *** fact demonstrates that they are almost *** EUV wave is most likely excited by the expanding loop structure and shows two *** leading component is a fast coronal wave,and the trailing one could be due to the stretching magnetic field lines.

关键词： coronal loops solar flares solar prominence solar oscillations extreme-ultraviolet wave magnetohydrodynamic

Revisiting the spin effects induced by thermal vorticity

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Chinese physics C 2024年第5期48卷 194-208页

作者：高建华杨诗正 Shandong key laboratory of Optical Astronomy and solar-Terrestrial Environment School of Space Science and PhysicsShandong UniversityWeihai 264209China Institute of Frontier and Interdisciplinary science Key Laboratory of Particle Physics and Particle Irradiation(MOE)Shandong UniversityQingdao 266237China

We revisit the spin effects induced by thermal vorticity by calculating them directly from the spin-dependent distribution *** spin-1/2 particles,we provide the polarization up to the first order of thermal vorticity and compare it with the usual results calculated from the spin *** spin-1 particles,we show that all the non-diagonal elements vanish and there is no spin alignment up to the first order of thermal *** present the spin alignment at second-order contribution from thermal *** also show that the spin effects for both Dirac and vector particles receive an extra contribution when the spin direction is associated with the momentum of the particle.

关键词： relativistic heavy ion collisions global polarization quark gluon plasma

A Possible γ-Ray Pulsation from PSR J1740-5340B in the Globular Cluster NGC 6397

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Research in Astronomy and Astrophysics 2024年第1期24卷 285-291页

作者： Jiao Zheng Pengfei Zhang Li Zhang Department of Astronomy School of Physics and AstronomyKey Laboratory of Astroparticle Physics of Yunnan ProvinceYunnan UniversityKunming 650091China

Recently, a new radio millisecond pulsar(MSP) J1740-5340B, hosted in the globular cluster(GC) NGC 6397,was reported with a 5.78 ms spin period in an eclipsing binary system with a 1.97 days orbital period. Based on a modified radio ephemeris updated by tool tempo2, we analyze the ~15 yr γ-ray data obtained from the Large Area Telescope on board the Fermi Gamma-ray space Telescope and detect PSR J1740-5340B's γ-ray pulsation at a confidence level of ~4σ with a weighted H-test value of ~26. By performing a phase-resolved analysis, the γ-ray luminosity in on-pulse interval of PSR J1740-5340B is L_(γ)~ 3.8 × 10^(33) erg s^(-1) using NGC 6397's distance of 2.48 kpc. And γ-rays from the on-pulse part of PSR J1740-5340B contribute ~90% of the total observed γ-ray emissions from NGC 6397. No significant γ-ray pulsation of another MSP J1740-5340A in the GC is *** that the previous four cases of MSPs in GCs, more data in γ-ray, X-ray, and radio are encouraged to finally confirm the γ-ray emissions from MSP J1740-5340B, especially starving for a precise ephemeris.

关键词： gamma-rays:galaxies (stars:)pulsars:individual(PSR J1740-5340B) (Galaxy:)globular clusters:individual(NGC 6397)

Feedback of Efficient Shock Acceleration on Magnetic-field Structure Inside Young Type Ia Supernova Remnants

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Research in Astronomy and Astrophysics 2024年第6期24卷 234-244页

作者： Jun-Yu Shen Bi-Wen Bao Li Zhang Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan ProvinceYunnan UniversityKunming 650091China key laboratory of Statistical Modeling and Data Analysis of yunnan Province Yunnan UniversityKunming 650091China

Using an effective adiabatic index γ_(eff) to mimic the feedback of efficient shock acceleration,we simulate the temporal evolution of a young type Ia supernova remnant (SNR) with two different background magnetic field(BMF) topologies:a uniform and a turbulent *** density distribution and magnetic-field characteristics of our benchmark SNR are studied with two-dimensional cylindrical magnetohydrodynamic *** γ_(eff)is considered,we find that:(1) the two-shock structure shrinks and the downstream magnetic-field orientation is dominated by the Rayleigh–Taylor instability structures;(2) there exists more quasi-radial magnetic fields inside the shocked region;and (3) inside the intershock region,both the quasi-radial magnetic energy density and the total magnetic energy density are enhanced:in the radial direction,with γ_(eff)=1.1,they are amplified about 10–26 times more than those with γ_(eff)=5/*** in the angular direction,the total magnetic energy densities could be amplified about 350 times more than those with γ_(eff)=5/3,and there are more grid cells within the intershock region where the magnetic energy density is amplified by a factor greater than 100.

关键词： methods:numerical ISM:magnetic fields ISM:supernova remnants magnetohydrodynamics(MHD)

Anisotropic s-Wave Gap in the Vicinity of a Quantum Critical Point in Superconducting BaFe_(2)(As_(1-x)P_(x))_(2) Single Crystals:A Study of Point-Contact Spectroscopy

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Chinese physics Letters 2024年第4期41卷 118-123页

作者：詹红星林玉尺赵宇清左海艳王兴玉马肖燕李春红罗会仟陈根富李世亮任聪 School of physics and Astronomy Yunnan UniversityKunming 650500China Beijing National laboratory for Condensed Matter physics and Institute of PhysicsChinese Academy of SciencesBeijing 100190China yunnan key laboratory for Electromagnetic Materials and Devices Yunnan UniversityKunming 650500China

We report on soft c-axis point-contact Andreev reflection(PCAR)spectroscopy combining with resistivity measurements on BaFe_(2)(As_(0.7)P_(0.3))_(2),to elucidate the superconducting gap structure in the vicinity of the quantum critical point.A double peak at the gap edge plus a dip feature at zero-bias has been observed on the PCAR spectra,indicative of the presence of a nodeless gap in BaFe_(2)(As_(0.7)P_(0.3))_(2).Detailed analysis within a sophisticated theoretical model reveals an anisotropic gap with deep gap *** PCARs also feature additional structures related to the electron-bosonic coupling *** the extracted superconducting energy gap value,a characteristic bosonic energy Ω_(b) and its temperature dependence are obtained,comparable with the spin-resonance energy observed in neutron scattering *** results indicate a magnetism-driven quantum critical point in the BaFe_(2)(As_(1-x)P_(x))_(2) system.

关键词： quantum critical resistivity

Long-term Variation of the solar Polar Magnetic Fields at Different Latitudes

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Research in Astronomy and Astrophysics 2024年第7期24卷 193-200页

作者： Shuhong Yang Jie Jiang Zifan Wang Yijun Hou Chunlan Jin Qiao Song Yukun Luo Ting Li Jun Zhang Yuzong Zhang Guiping Zhou Yuanyong Deng Jingxiu Wang National Astronomical Observatories Chinese Academy of Sciences School of Astronomy and space science University of Chinese Academy of Sciences State key laboratory of solar Activity and space Weather National Space Science CenterChinese Academy of Sciences School of space and Environment Beihang University key laboratory of space Weather National Satellite Meteorological Center (National Center for Space Weather) Innovation Center for FengYun Meteorological Satellite (FYSIC) School of physics and Materials science Anhui University

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 *** 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.

关键词： dynamo Sun: magnetic fields Sun: photosphere

Scientific objectives and payload configuration of the Chang'E-7 mission

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National science Review 2024年第2期11卷 285-300页

作者： Chi Wang Yingzhuo Jia Changbin Xue Yangting Lin Jianzhong Liu Xiaohui Fu Lin Xu Yun Huang Yufen Zhao Yigang Xu Rui Gao Yong Wei Yuhua Tang Dengyun Yu Yongliao Zou China Aerospace science and Technology Corporation State key laboratory of space Weather National Space Science Center Chinese Academy of Sciences National space science Center Chinese Academy of Sciences Institute of Geology and Geophysics Chinese Academy of Sciences Institute of Geochemistry Chinese Academy of Sciences Shandong Provincial key laboratory of Optical Astronomy and solar-Terrestrial Environment School of Space Science and Physics Institute of Space SciencesShandong University Institute of Drug Discovery Technology Ningbo University State key laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences School of Earth science and Engineering Sun Yat-sen University Lunar Exploration and space Engineering Center

As the cornerstone mission of the fourth phase of the Chinese Lunar Exploration Program, Chang'E-7(CE-7) was officially approved, and implementation started in 2022, including a main probe and a communication relay satellite. The main probe, consisting of an orbiter, a lander, a rover and a mini-flying probe, is scheduled to be launched in 2026. The lander will land on Shackleton crater's illuminated rim near the lunar south pole, along with the rover and mini-flying probe. The relay satellite(named Queqiao-2) will be launched in February 2024 as an independent mission to support relay communication during scientific exploration undertaken by Chang'E-4, the upcoming Chang'E-6 in 2024 and subsequent lunar *** CE-7 mission is mainly aimed at scientific and resource exploration of the lunar south pole. We present CE-7's scientific objectives, the scientific payloads configuration and the main functions for each scientific payload with its key technical specifications.

关键词： Chang’ E-7 scientific objectives scientific payloads