logo

SCIENCE CHINA Technological Sciences, Volume 63 , Issue 9 : 1656-1674(2020) https://doi.org/10.1007/s11431-019-1463-6

Research progress based on observations of the New Vacuum Solar Telescope

More info
  • ReceivedJun 14, 2019
  • AcceptedOct 14, 2019
  • PublishedApr 24, 2020

Abstract

The purpose of this paper is to introduce the main scientific results made by the one-meter New Vacuum Solar Telescope (NVST), which was put into commission on 2010. NVST is one of the large aperture solar telescopes in the world, located on the shore of Fuxian lake of Yunnan province in China, aiming at serving solar physicists by providing them with high resolution photospheric and chromospheric observational data. Based on the data from NVST and complementary observations from space (e.g., Hinode, SDO and IRIS, etc), dozens of scientific papers have been published with a wide range of topics concentrating mainly on dynamics and activities of fine-scale magnetic structures and their roles in the eruptions of active-region filaments and flares. The achievements include dynamic characteristics of photospheric bright points, umbral dots, penumbral waves, and sunspot/light bridge oscillation, observational evidence of small-scale magnetic reconnection, and fine-scale dynamic structure of prominences. All these new results will shed light on the better understanding of solar eruptive activities. Data release, observation proposals, and future research subjects are introduced and discussed.


Acknowledgment

We would like to thank the NVST, SDO/AIA, SDO/HMI teams for high-cadence data support. This work was supported by the National Natural Science Foundation of China (Grant Nos. 11873087, 11633008), the Youth Innovation Promotion Association CAS (Grant No. 2011056), the Yunnan Talent Science Foundation of China (Grant No. 2018FA001), the Project Supported by the Specialized Research Fund for State Key Laboratories, and the grant associated with project of the Group for Innovation of Yunnan Province.


References

[1] Liu Z, Xu J, Gu B Z. New vacuum solar telescope and observations with high resolution. Res Astron Astrophys, 2014, 14: 705-718 CrossRef ADS Google Scholar

[2] Xu Z , Jin Z Y , Xu F Y , et al. Primary observations of solar filaments using the multi-channel imaging system of the New Vacuum Solar Telescope. Proceedings of the International Astronomical Union, 2014, 8: 117-120. Google Scholar

[3] Wang R, Xu Z, Jin Z Y. The first observation and data reduction of the Multi-wavelength Spectrometer on the New Vacuum Solar Telescope. Res Astron Astrophys, 2013, 13: 1240-1254 CrossRef ADS Google Scholar

[4] Cai Y F, Xu Z, Chen Y C. Method of composing two-dimensional scanned spectra observed by the New Vacuum Solar Telescope. Res Astron Astrophys, 2018, 18: 042-52 CrossRef ADS arXiv Google Scholar

[5] Xiang Y Y , Liu Z , Jin Z Y . High resolution reconstruction of solar prominence images observed by the New Vacuum Solar Telescope. New Astronomy, 2016, 49: 8-12. Google Scholar

[6] Weigelt G P. Modified astronomical speckle interferometry 'speckle masking'. Optics Commun, 1977, 21: 55-59 CrossRef ADS Google Scholar

[7] Liu Z , Qui Y , Ke L , et al. New progress in the high resolution speckle imaging at Yunnan Observatory. Acta Astronomica Sinica, 1998, 39: 217-224. Google Scholar

[8] Zhu X, Wang H, Du Z. Astrophys J, 2016, 826: 51-58 CrossRef ADS arXiv Google Scholar

[9] Cai Y, Xu Z, Li Z. Precise Reduction of Solar Spectra Observed by the One-Meter New Vacuum Solar Telescope. Sol Phys, 2017, 292: 150-163 CrossRef ADS arXiv Google Scholar

[10] Ji K F , Xiong J P , Xiang Y Y , et al. Investigation of intergranular bright points from the New Vacuum Solar Telescope. Research In Astronomy And Astrophysics, 2016, 16: 69-80. Google Scholar

[11] Feng S, Deng L, Yang Y. Statistical study of photospheric bright points in an active region and quiet Sun. Astrophys Space Sci, 2013, 348: 17-24 CrossRef ADS Google Scholar

[12] Liu Y, Xiang Y, Erdélyi R. Studies of Isolated and Non-isolated Photospheric Bright Points in an Active Region Observed by the New Vacuum Solar Telescope. Astrophys J, 2018, 856: 17 CrossRef ADS Google Scholar

[13] Yang Y F, Lin J B, Feng S. Evolution of isolated G-band bright points: size, intensity and velocity. Res Astron Astrophys, 2014, 14: 741-752 CrossRef ADS Google Scholar

[14] Ji H, Cao W, Goode P R. Observation of Ultrafine Channels of Solar Corona Heating. Astrophys J, 2012, 750: L25 CrossRef ADS Google Scholar

[15] Ji K, Jiang X, Feng S. Investigation of Umbral Dots with the New Vacuum Solar Telescope. Sol Phys, 2016, 291: 357-369 CrossRef ADS arXiv Google Scholar

[16] Feng S, Xu Z, Wang F. Automated Detection of Low-Contrast Solar Features Using the Phase-Congruency Algorithm. Sol Phys, 2014, 289: 3985-3994 CrossRef ADS Google Scholar

[17] Su J T, Ji K F, Cao W. Observations of Oppositely Directed Umbral Wavefronts Rotating in Sunspots Obtained from the New Solar Telescope of BBSO. Astrophys J, 2016, 817: 117-133 CrossRef ADS Google Scholar

[18] Just O, Obergaulinger M, Janka H T. Neutron-star Merger Ejecta as Obstacles to Neutrino-powered Jets of Gamma-Ray Bursts. Astrophys J, 2016, 816: L30-41 CrossRef ADS arXiv Google Scholar

[19] Wang F, Deng H, Li B. High-frequency Oscillations in the Atmosphere above a Sunspot Umbra. Astrophys J, 2018, 856: L16 CrossRef ADS arXiv Google Scholar

[20] Zhou X, Liang H. The relationship between the 5-min oscillation and 3-min oscillations at the umbral/penumbral sunspot boundary. Astrophys Space Sci, 2017, 362: 46-56 CrossRef ADS Google Scholar

[21] Zhou X, Liang H F, Li Q H. Statistical research of the umbral and penumbral oscillations. New Astron, 2017, 51: 86-95 CrossRef ADS Google Scholar

[22] Yang S, Zhang J, Jiang F. Oscillating Light Wall Above a Sunspot Light Bridge. Astrophys J, 2015, 804: L27 CrossRef ADS arXiv Google Scholar

[23] Hou Y J , Li T , Yang S H , et al. Light Walls Around Sunspots Observed by the Interface Region Imaging Spectrograph. Astronomy & Astrophysics, 2016, 589: L7-L11. Google Scholar

[24] Tian H, Yurchyshyn V, Peter H. Frequently Occurring Reconnection Jets from Sunspot Light Bridges. Astrophys J, 2018, 854: 92-105 CrossRef ADS arXiv Google Scholar

[25] Forbes T G. A review on the genesis of coronal mass ejections. J Geophys Res, 2000, 105: 23153-23165 CrossRef ADS Google Scholar

[26] Martin S F. Conditions for the Formation and Maintenance of Filaments (Invited Review). Sol Phys, 1998, 182: 107-137 CrossRef ADS Google Scholar

[27] Yan X L, Xue Z K, Xiang Y Y. Fine-scale structures and material flows of quiescent filaments observed by the New Vacuum Solar Telescope. Res Astron Astrophys, 2015, 15: 1725-1734 CrossRef ADS arXiv Google Scholar

[28] Li H, Liu Y, Tam K V. Piecewise mass flows within a solar prominence observed by the New Vacuum Solar Telescope. Astrophys Space Sci, 2018, 363: 118-123 CrossRef ADS Google Scholar

[29] Shen Y, Liu Y, Liu Y D. Fine Magnetic Structure and Origin of Counter-streaming Mass Flows in a Quiescent Solar Prominence. Astrophys J, 2015, 814: L17 CrossRef ADS arXiv Google Scholar

[30] Yang H, Xu Z, Lim E K. Observation of the Kelvin-Helmholtz Instability in a Solar Prominence. Astrophys J, 2018, 857: 115-124 CrossRef ADS Google Scholar

[31] Li D, Shen Y, Ning Z. Two Kinds of Dynamic Behavior in a Quiescent Prominence Observed by the NVST. Astrophys J, 2018, 863: 192-203 CrossRef ADS arXiv Google Scholar

[32] Yan X L, Xue Z K, Pan G M. The Formation and Magnetic Structures of Active-region Filaments Observed by NVST, SDO, and Hinode. Astrophys J Suppl Ser, 2015, 219: 17-36 CrossRef ADS Google Scholar

[33] Yan X L, Priest E R, Guo Q L. The Formation of an Inverse S-shaped Active-region Filament Driven by Sunspot Motion and Magnetic Reconnection. Astrophys J, 2016, 832: 23-35 CrossRef ADS arXiv Google Scholar

[34] Guo Y, Cheng X, Ding M D. Origin and structures of solar eruptions II: Magnetic modeling. Sci China Earth Sci, 2017, 60: 1408-1439 CrossRef ADS arXiv Google Scholar

[35] Xue Z, Yan X, Yang L. Observing Formation of Flux Rope by Tether-cutting Reconnection in the Sun. Astrophys J, 2017, 840: L23 CrossRef ADS Google Scholar

[36] Wang H, Liu C. Signatures of Magnetic Flux Ropes in the Low Solar Atmosphere Observed in High Resolution. Front Astron Space Sci, 2019, 6: 00018 CrossRef ADS Google Scholar

[37] Yang B , Jiang Y , Yang J , et al. The Rapid Formation Of A Filament Caused By Magnetic Reconnection Between Two Sets Of Dark Threadlike Structures. The Astrophysical Journal, 2016, 816: 41-50. Google Scholar

[38] Rodríguez-Kamenetzky A, Carrasco-González C, Araudo A. Investigating Particle Acceleration in Protostellar Jets: The Triple Radio Continuum Source in Serpens. Astrophys J, 2016, 818: 27-34 CrossRef ADS arXiv Google Scholar

[39] Antiochos S K, Dahlburg R B, Klimchuk J A. The magnetic field of solar prominences. Astrophys J, 1994, 420: L41-L44 CrossRef ADS Google Scholar

[40] DeVore C R, Antiochos S K. Dynamical Formation and Stability of Helical Prominence Magnetic Fields. Astrophys J, 2000, 539: 954-963 CrossRef ADS Google Scholar

[41] Demoulin P , Priest E R . A twisted flux model for solar prominences. II - Formation of a dip in a magnetic structure before the formation of a solar prominence. Astronomy and Astrophysics, 1989, 214: 360-368. Google Scholar

[42] Amari T, Luciani J F, Mikic Z. A Twisted Flux Rope Model for Coronal Mass Ejections and Two-Ribbon Flares. Astrophys J, 2000, 529: L49-L52 CrossRef ADS Google Scholar

[43] Jiang C, Wu S T, Feng X. Nonlinear Force-free Field Extrapolation of a Coronal Magnetic Flux Rope Supporting a Large-scale Solar Filament from a Photospheric Vector Magnetogram. Astrophys J, 2014, 786: L16 CrossRef ADS arXiv Google Scholar

[44] Su Y , van Ballegooijen A, McCauley P, et al. Magnetic Structure and Dynamics of the Erupting Solar Polar Crown Prominence on 2012 March 12.The Astrophysical Journal, 2015, 807: 144-161. Google Scholar

[45] Yang S, Zhang J, Liu Z. New Vacuum Solar Telescope Observations of a Flux Rope Tracked by a Filament Activation. Astrophys J, 2014, 784: L36 CrossRef ADS arXiv Google Scholar

[46] Egusa F, Usui F, Murata K. Revised calibration for near- and mid-infrared images from ~4000 pointed observations with AKARI/IRC. Publ Astron Soc Jpn, 2016, 68: 19 CrossRef ADS arXiv Google Scholar

[47] Chen H, Zheng R, Li L. Untwisting and Disintegration of a Solar Filament Associated with Photospheric Flux Cancellation. Astrophys J, 2019, 871: 229-240 CrossRef ADS arXiv Google Scholar

[48] Awasthi A K, Liu R, Wang Y. Double-decker Filament Configuration Revealed by Mass Motions. Astrophys J, 2019, 872: 109-120 CrossRef ADS arXiv Google Scholar

[49] Hood A W, Priest E R. Kink instability of solar coronal loops as the cause of solar flares. Sol Phys, 1979, 64: 303-321 CrossRef ADS Google Scholar

[50] T?r?k T, Kliem B. Confined and Ejective Eruptions of Kink-unstable Flux Ropes. Astrophys J, 2005, 630: L97-L100 CrossRef ADS Google Scholar

[51] Kliem B, T?r?k T. Torus Instability. Phys Rev Lett, 2006, 96: 255002 CrossRef PubMed ADS Google Scholar

[52] Antiochos S K, DeVore C R, Klimchuk J A. A Model for Solar Coronal Mass Ejections. Astrophys J, 1999, 510: 485-493 CrossRef ADS Google Scholar

[53] Moore R L, Sterling A C, Hudson H S. Onset of the Magnetic Explosion in Solar Flares and Coronal Mass Ejections. Astrophys J, 2001, 552: 833-848 CrossRef ADS Google Scholar

[54] Forbes T G, Isenberg P A. A catastrophe mechanism for coronal mass ejections. Astrophys J, 1991, 373: 294-307 CrossRef ADS Google Scholar

[55] Lin J, Forbes T G. Effects of reconnection on the coronal mass ejection process. J Geophys Res, 2000, 105: 2375-2392 CrossRef ADS Google Scholar

[56] Wang J C, Yan X L, Qu Z Q , et al. The Evolution of the Electric Current during the Formation and Eruption of Active-region Filaments The Astrophysical Journal, 2016, 817: 156-166. Google Scholar

[57] Bi Y, Jiang Y, Yang J. Partial Eruption of a Filament with Twisting Non-uniform Fields. Astrophys J, 2015, 805: 48-56 CrossRef ADS arXiv Google Scholar

[58] Cheng X, Kliem B, Ding M D. Unambiguous Evidence of Filament Splitting-induced Partial Eruptions. Astrophys J, 2018, 856: 48-63 CrossRef ADS arXiv Google Scholar

[59] Li S, Su Y, Zhou T. High-resolution Observations of Sympathetic Filament Eruptions by NVST. Astrophys J, 2017, 844: 70-83 CrossRef ADS arXiv Google Scholar

[60] Zhou G P, Zhang J, Wang J X. A Study of External Magnetic Reconnection that Triggers a Solar Eruption. Astrophys J, 2017, 851: L1 CrossRef ADS Google Scholar

[61] Yang B, Chen H. Filament Eruption and Its Reformation Caused by Emerging Magnetic Flux. Astrophys J, 2019, 874: 96-110 CrossRef ADS arXiv Google Scholar

[62] Zhang J, Yang S, Li T. Magnetic Reconnection: From “Open” Extreme-ultraviolet Loops to Closed Post-flare Ones Observed by SDO. Astrophys J, 2013, 776: 57-66 CrossRef ADS Google Scholar

[63] Su Y, Veronig A M, Holman G D. Imaging coronal magnetic-field reconnection in a solar flare. Nat Phys, 2013, 9: 489-493 CrossRef ADS arXiv Google Scholar

[64] Tian H, Li G, Reeves K K. Imaging and Spectroscopic Observations of Magnetic Reconnection and Chromospheric Evaporation in a Solar Flare. Astrophys J, 2014, 797: L14 CrossRef ADS arXiv Google Scholar

[65] Xue Z, Yan X, Cheng X. Observing the release of twist by magnetic reconnection in a solar filament eruption. Nat Commun, 2016, 7: 11837 CrossRef PubMed ADS Google Scholar

[66] Li L, Zhang J, Peter H. Magnetic reconnection between a solar filament and nearby coronal loops. Nat Phys, 2016, 12: 847-851 CrossRef ADS arXiv Google Scholar

[67] Yang S, Zhang J, Xiang Y. Magnetic reconnection between small-scale loops observed with the New Vacuum Solar Telescope.The Astrophysical Journal Letters, 2015, 798: L11-L17. Google Scholar

[68] Yang S, Xiang Y. Oscillation of Newly Formed Loops after Magnetic Reconnection in the Solar Chromosphere. Astrophys J, 2016, 819: L24 CrossRef ADS arXiv Google Scholar

[69] Crooker N U , Gosling J T , Kahler S W . Reducing heliospheric magnetic flux from coronal mass ejections without disconnection. Journal of Geophysical Research (Space Physics), 2002, 107: 1028-1033. Google Scholar

[70] Wang Y M, Sheeley, Jr. N R, Walters J H. Origin of Streamer Material in the Outer Corona. Astrophys J, 1998, 498: L165-L168 CrossRef ADS Google Scholar

[71] Fisk L A , Schwadron N A , Zurbuchen T H . Acceleration of the fast solar wind by the emergence of new magnetic flux. Journal of Geophysical Research, 1999, 104: 19765-19772. Google Scholar

[72] Kong D F, Pan G M, Yan X L. Observational Evidence of Interchange Reconnection between a Solar Coronal Hole and a Small Emerging Active Region. Astrophys J, 2018, 863: L22 CrossRef ADS Google Scholar

[73] Yu Y W, Zhu J P, Li S Z. A Statistical Study of Superluminous Supernovae Using the Magnetar Engine Model and Implications for Their Connection with Gamma-Ray Bursts and Hypernovae. Astrophys J, 2017, 840: 12 CrossRef ADS arXiv Google Scholar

[74] Huang Z, Mou C, Fu H. A Magnetic Reconnection Event in the Solar Atmosphere Driven by Relaxation of a Twisted Arch Filament System. Astrophys J, 2018, 853: L26 CrossRef ADS arXiv Google Scholar

[75] Yang L, Yan X, Li T. Interaction of Two Active Region Filaments Observed by NVST and SDO. Astrophys J, 2017, 838: 131-139 CrossRef ADS arXiv Google Scholar

[76] Xue Z, Yan X, Jin C. A Small-scale Oscillatory Reconnection and the Associated Formation and Disappearance of a Solar Flux Rope. Astrophys J, 2019, 874: L27 CrossRef ADS Google Scholar

[77] Mei Z X, Keppens R, Roussev I I. Parametric study on kink instabilities of twisted magnetic flux ropes in the solar atmosphere. Astron Astrophys, 2018, 609: A2 CrossRef ADS Google Scholar

[78] Ni L, Kliem B, Lin J. Fast Magnetic Reconnection in the Solar Chromosphere Mediated by the Plasmoid Instability. Astrophys J, 2015, 799: 79-95 CrossRef ADS arXiv Google Scholar

[79] Mei Z X, Keppens R, Roussev I I. Magnetic reconnection during eruptive magnetic flux ropes. Astron Astrophys, 2017, 604: L7 CrossRef ADS Google Scholar

[80] Ye J , Lin J , Raymond J C , et al. Numerical Study of the Cascading Energy Conversion of the Reconnecting Current Sheet in Solar Eruptions.Monthly Notices of the Royal Astronomical Society, 2017, 482: 588-605. Google Scholar

[81] Ellerman F. Solar Hydrogen “bombs”. Astrophys J, 1917, 46: 298-302 CrossRef ADS Google Scholar

[82] De Pontieu B, Title A M, Lemen J R. The Interface Region Imaging Spectrograph (IRIS). Sol Phys, 2014, 289: 2733-2779 CrossRef ADS arXiv Google Scholar

[83] Peter H, Tian H, Curdt W. Hot explosions in the cool atmosphere of the Sun. Science, 2014, 346: 1255726-1255726 CrossRef PubMed ADS arXiv Google Scholar

[84] Tian H, Xu Z, He J. Are IRIS Bombs Connected to Ellerman Bombs?. Astrophys J, 2016, 824: 96-110 CrossRef ADS arXiv Google Scholar

[85] Chen Y, Tian H, Xu Z. Ellerman bombs observed with the new vacuum solar telescope and the atmospheric imaging assembly onboard the solar dynamics observatory. Geosci Lett, 2017, 4: 30-35 CrossRef ADS Google Scholar

[86] Ni L, Lin J, Roussev I I. Heating Mechanisms in the Low Solar Atmosphere through Magnetic Reconnection in Current Sheets. Astrophys J, 2016, 832: 195-206 CrossRef ADS arXiv Google Scholar

[87] Fang C, Hao Q, Ding M D. Can the temperature of Ellerman Bombs be more than 10 000 K?. Res Astron Astrophys, 2017, 17: 031-37 CrossRef ADS arXiv Google Scholar

[88] Hong J, Jiang Y, Yang J. Minifilament Eruption as the Source of a Blowout Jet, C-class Flare, and Type-III Radio Burst. Astrophys J, 2017, 835: 35-46 CrossRef ADS Google Scholar

[89] Tian Z, Liu Y, Shen Y. Successive Two-sided Loop Jets Caused by Magnetic Reconnection between Two Adjacent Filamentary Threads. Astrophys J, 2017, 845: 94-102 CrossRef ADS arXiv Google Scholar

[90] Shen Y, Liu Y D, Su J. On a Solar Blowout Jet: Driving Mechanism and the Formation of Cool and Hot Components. Astrophys J, 2017, 851: 67-80 CrossRef ADS arXiv Google Scholar

[91] Zheng R, Chen Y, Huang Z. Two-sided-loop Jets Associated with Magnetic Reconnection between Emerging Loops and Twisted Filament Threads. Astrophys J, 2018, 861: 108-119 CrossRef ADS arXiv Google Scholar

[92] Li H, Yang J. A Fan Spine Jet: Nonradial Filament Eruption and the Plasmoid Formation. Astrophys J, 2019, 872: 87-96 CrossRef ADS Google Scholar

[93] Svestka Z , Jackson B V , Machado M E . Eruptive Solar Flares. Lecture Notes in Physics, 1992, 399: 1. Google Scholar

[94] Yang S, Zhang J, Xiang Y. Fine Structures and Overlying Loops of Confined Solar Flares. Astrophys J, 2014, 793: L28 CrossRef ADS arXiv Google Scholar

[95] Liu S, Zhang H Q, Choudhary D P. Superpenumbral chromospheric flare. Res Astron Astrophys, 2018, 18: 130-140 CrossRef ADS arXiv Google Scholar

[96] Xu Z, Yang J, Ji K. Magnetic Field Rearrangement in the Photosphere Driven by an M5.0 Solar Flare. Astrophys J, 2019, 874: 134-143 CrossRef ADS Google Scholar

[97] Li H, Yang J, Jiang Y. The surge-like eruption of a miniature filament associated with circular flare ribbon. Astrophys Space Sci, 2018, 363: 26-31 CrossRef ADS Google Scholar

[98] Xu Z, Yang K, Guo Y. Homologous Circular-ribbon Flares Driven by Twisted Flux Emergence. Astrophys J, 2017, 851: 30-41 CrossRef ADS Google Scholar

[99] Song Y, Tian H. Investigation of White-light Emission in Circular-ribbon Flares. Astrophys J, 2018, 867: 159-172 CrossRef ADS arXiv Google Scholar

[100] Song, Y. L., Guo, Y., Tian, H., Zhu, X. S., Zhang, M., Zhu, Y. J. Observations of a White-light Flare Associated with a Filament Eruption. The Astrophysical Journal, 2018, 854, 64-86. Google Scholar

[101] Yan X L, Qu Z Q, Kong D F. Relationship between rotating sunspots and flare productivity. Mon Not R Astron Soc, 2008, 391: 1887-1892 CrossRef ADS Google Scholar

[102] Yan X L, Wang J C, Pan G M. Successive X-class Flares and Coronal Mass Ejections Driven by Shearing Motion and Sunspot Rotation in Active Region NOAA 12673. Astrophys J, 2018, 856: 79-93 CrossRef ADS arXiv Google Scholar

[103] Yang Y, Li Q, Ji K. On the Relationship Between G-Band Bright Point Dynamics and Their Magnetic Field Strengths. Sol Phys, 2016, 291: 1089-1105 CrossRef ADS arXiv Google Scholar

[104] Mackay D H, Karpen J T, Ballester J L. Physics of Solar Prominences: IIMagnetic Structure and Dynamics. Space Sci Rev, 2010, 151: 333-399 CrossRef ADS arXiv Google Scholar

[105] Yan X L, Qu Z Q. Rapid rotation of a sunspot associated with flares. Astronomy & Astrophysics, 2007, 468: 1083-1088. Google Scholar

[106] Yan X L, Qu Z Q, Xu C L. The causality between the rapid rotation of a sunspot and an X3.4 flare. Res Astron Astrophys, 2009, 9: 596-602 CrossRef ADS arXiv Google Scholar

[107] Su Y , Golub L , Van Ballegooijen A , et al. Evolution of the Sheared Magnetic Fields of Two X-Class Flares Observed by Hinode/XRT. Publications of the Astronomical Society of Japan, 2007, 5: S785-S791. Google Scholar

  • Figure 1

    (Color online) High resolution observation of photosphere and chromosphere. (a) A complex active-region NOAA 12673 in TiO image observed by the NVST at 03:45:18 UT on September 5, 2017. This active-region includes several sunspots and pores. The large sunspots are hosting light bridge. (b) Fine structure of a quiescent filament observed at H$\alpha$ line center by the NVST at 05:31:01 UT on July 23, 2018.

  • Figure 2

    (Color online) Two different bright points observed by the NVST. (a)–(e) Evolution of the isolated bright points (BPs); (f)–(j) evolution of the non-isolated BPs. Image reproduced with permission from Liu et al. (2018), copyright by AAS.

  • Figure 3

    (Color online) High-resolution H$\alpha$ image of the quiescent filament observed by NVST at 05:53:07 UT on November 2, 2012. The lines in (b) and (d) mark the areas that have material flows with the same di- rection and the lines in (c) denote material flows in opposite directions. The lines in (a) marked by the numbers indicate the positions of the time slices shown in Figure 5(b)–(d). Image reproduced from Yan et al. (2015), copyright by RAA.

  • Figure 4

    (Color online) A limb prominence and the counter-streaming. (a) A quiescent prominence observed by the NVST; (b)–(e) the time-distance diagrams showing the mass dynamical motion along the slit A1, A2, B1, and B2. Image reproduced with permission from Shen et al. (2015), copyright by AAS.

  • Figure 5

    (Color online) Evolution of a quiescent prominence observed by the NVST in off-band H$\alpha$ image. (a)–(c) H$\alpha$ +0.3 Å images; (d) line-of-sight velocity. The curved arrows indicate the vortex flow in the quiescent prominence. Image reproduced with permission from Li et al. (2018), copyright by AAS.

  • Figure 6

    (Color online) The formation of the active-region filaments observed by the NVST and its magnetic structure. (a), (b) H$\alpha$ images observed at 02:00:05 UT on October 31, 2013 and at 08:00:07 UT on November 1 by NVST superimposed on the corresponding line-of-sight magnetogram observed by the SDO/HMI. The contours indicate the positive and negative polarities. The contour levels are $\pm$500 G and $\pm$1000 G. The arrows indicate the small sunspot and the active-region filament. (c) The vector magnetogram observed by SDO/HMI at 19:36:00 UT on November 1. (d) The extrapolation of the filament structure and the surrounding magnetic fields of the filament superimposed on the longitudinal magnetic fields. Image reproduced from Yan et al. (2015), copyright by AAS.

  • Figure 7

    (Color online) Formation of an active-region filament observed by the NVST and the extrapolation magnetic fields by using NLFFF model. (a1–a3) H$\alpha$ images observed by the NVST; (b1–b3) the extrapolations based on the vector magnetograms observed by SDO/HMI. Image reproduced from Yan et al. (2016), copyright by AAS.

  • Figure 8

    (Color online) Formation of an active-region filament observed by the NVST. L1 and L2 indicate the left and the right part of the chromospheric fibrils marked by curved lines in (a). The curved line in (b) indicates the newly formed filament. Image reproduced with permission from Xue et al. (2017), copyright by AAS.

  • Figure 9

    (Color online) Vector magnetograms and electric currents along the axis of the filaments. (a), (b) Vector magnetograms observed by the SDO/HMI; (c), (d) the electric currents along the axis of the filaments derived from the extrapolated 3-D magnetic fields by using NLFFF model. The lines indicate the positions of the cross-section of the electric currents perpendicular to the filaments. Image reproduced with permission from Wang et al. (2016), copyright by AAS.

  • Figure 10

    (Color online) A small-scale magnetic reconnection observed by the NVST. L1 and L2 indicate the two groups of the chromospheric fibrils before the magnetic reconnection. L3 and L4 indicate the newly formed chromospheric fibrils after the magnetic reconnection. The box indicates the reconnection region. Image reproduced with permission from Yang et al. (2014), copyright by AAS.

  • Figure 11

    (Color online) The reconnection process of an active-region filament and the chromospheric fibrils observed by the NVST. The filament threads and chromospheric fibrils are indicated by arrows respectively in panels (a) and (b). The current sheet forming in magnetic reconnection is marked by the arrows in panels (c)–(f). The results of a data-constrained magnetohydrodynamic simulation reproducing the magnetic reconnection during the filament eruption are presented in panels (g)–(i). Image reproduced with permission from Xue et al. (2016), copyright by NPG.

  • Figure 12

    (Color online) Interaction between two active-region filaments observed by the NVST. F1 and F2 indicate the two active-region filaments. The dashed lines in (b), (c) outline the newly formed filament threads and the red arrows indicate the brightening caused by the interaction of the two filaments. Image reproduced with permission from Yang et al. (2017), copyright by AAS.

  • Figure 13

    (Color online) IRIS bomb and EB bomb observed by the NVST and IRIS. IRIS/SJI 1400 Å image, and NVST H$\alpha$ core and wing (–1 Å and +1 Å) images taken around 03:05:38 UT. The dark filamentary structures in the H$\alpha$ wings, especially in the blue wing, are chromospheric spicules which could affect the detection of EBs. (e)–(h) Images of the Si IV 1393.755 Å intensity, Mg II k core and wing (sum of –1.33 Å and +1.33 Å), and Si IV 1393.755 Å line width. The locations of the IBs are marked by overplotting contours of the Si IV 1393.755 Å peak intensity. The white line in each panel indicates the slit location at 03:07:28 UT. Image reproduced with permission from Tian et al. (2016), copyright by AAS.

  • Figure 14

    (Color online) Two blowout jets observed by the NVST. (a)–(d) Evolution of the first ejection stage of the blowout jet; (e)–(h) evolution of the second ejection stage of the blowout jet. Image reproduced with permission from Shen et al. (2018), copyright by AAS.

  • Figure 15

    (Color online) Process of a confined flare observed by the NVST. The dashed lines display the loops identified from H$\alpha$ images. Image reproduced with permission from Yang et al. (2014), copyright by AAS.

  • Figure 16

    (Color online) Active-region NOAA 12673 in the continuum intensity image, line-of-sigh magnetogram, and TiO images. (a) The continuum intensity image; (b) line-of-sigh magnetogram; (c)–(d) TiO images. Image reproduced from Yan et al. (2018), copyright by AAS.

  • Figure 17

    (Color online) A part of the sunspot groups in active-region NOAA 12673. (a) Vector magnetogram; (b) velocity field derived from vector magnetogram by using DAVE method; (c) a flux rope. Note that the field lines are the selected field lines extrapolated by using NLFFF method. Image reproduced from Yan et al. (2018), copyright by AAS.

  • Table 1  

    Table 1Main properties of the multi-wavelength optical-band spectrograph

    Item Parameter
    Grating size 156 mm$\times$220 mm
    Grooves per mm 1200 g/mm
    Blazed angle ($^{\circ}$) 36.8 (1st order, blazed wavelength 10000 Å
    Present slit width (microns) 100 (0.45 arcsec)
    Linear dispersion (mm/Å 0.75 @ H$\alpha$, 0.82 @ Ca II 8542, 2 @ Fe I 5324
    Raw spectra frame size (pixels) 2672$\times$4008
    Pixel size (microns) 9$\times$9
    Spectral sample (mÅ/pixel) 12 @ H$\alpha$, 11 @ Ca II 8542, 4.5 @ Fe I 5324
    Spatial sample (arcsec /pixel) 0.041
  • Table 2  

    Table 2Properties of the BPs of the six data sets. Table reproduced from Ji et al. (2016) [10], copyright by RAA

    Data set 1 2 3 4 5 6
    Area coverage 0.20%0.99% 1.55% 1.53% 1.75% 1.99%
    Equivalent diameter ($\rm~km$) 181$\pm$22 168$\pm$29 178$\pm$29 195$\pm$36 184$\pm$38 194$\pm$36
    [{min,max}] [{111,~245}] [{103,~402}] [{109,~440}] [{106,~445}] [{122,~447}] [{112,~473}]
    Intensity contrast 0.99$\pm$0.04 1.01$\pm$0.04 1.03$\pm$0.04 1.05$\pm$0.06 1.05$\pm$0.04 1.06$\pm$0.05
    [{min,max}] [{0.91,~1.12}] [{0.90,~1.19}] [{0.90,~1.31}] [{0.92,~1.30}] [{0.92,~1.24}] [{0.89,~1.28}]
    Lifetime ($\rm~s$) 104$\pm$104 133$\pm$133 114$\pm$114 141$\pm$141 121$\pm$121 124$\pm$124
    [{min,max}] [{103,~582}] [{102,~826}] [{120,~723}] [{119,~735}] [{120,~572}] [{114,~580}]
    Velocity ($\rm~km$ $\rm~s^{-1}$) 1.35$\pm$0.71 1.23$\pm$0.64 1.06$\pm$0.55 1.04$\pm$0.54 1.06$\pm$0.55 1.05$\pm$0.55
    [{min,max}] [{0.01,~5.27}] [{0,~6.80}] [{0.08,~5.43}] [{0.02,~5.32}] [{0.06,~5.21}] [{0.03,~5.75}]
    Diffusion index 1.31$\pm$0.65 1.21$\pm$0.78 0.91$\pm$0.43 1.05$\pm$0.67 0.86$\pm$0.49 0.93$\pm$0.77
    [{min,max}] [{--3.64,~3.93}] [{--4.91,~5.39}] [{--4.17,~4.28}] [{--5.21,~6.51}] [{--7.00,~4.21}] [{--5.70,~4.43}]
    Ratio of motion range 1.30$\pm$0.80 1.18$\pm$0.76 1.11$\pm$0.77 1.02$\pm$0.62 0.96$\pm$0.67 1.03$\pm$0.69
    [{min,max}] [{0.31,~5.06}] [{0.15,~6.39}] [{0.04,~6.28}] [{0.17,~5.42}] [{0.13,~4.73}] [{0.13,~4.79}]
    Motion type 0.69$\pm$0.69 0.69$\pm$0.69 0.58$\pm$0.58 0.59$\pm$0.59 0.59$\pm$0.59 0.62$\pm$0.62
    [{min,max}] [{0.08,~0.99}] [{0.04,~1.00}] [{0.23,~0.99}] [{0.03,~0.99}] [{0,~1.00}] [{0.04,~0.98}]

Copyright 2020  CHINA SCIENCE PUBLISHING & MEDIA LTD.  中国科技出版传媒股份有限公司  版权所有

京ICP备14028887号-23       京公网安备11010102003388号