More info
  • ReceivedFeb 25, 2020
  • AcceptedApr 14, 2020
  • PublishedMay 13, 2020


The concept of the Solar Ring mission was gradually formed from L5/L4 mission concept, and the proposal of its pre-phasestudy was funded by the National Natural Science Foundation of China in November 2018 and then by theStrategic Priority Program of Chinese Academy of Sciences in space sciences in May 2019. Solar Ring mission will be thefirst attempt to routinely monitor and study the Sun and inner heliosphere from a full $360$-degreeperspective in the ecliptic plane. The current preliminary design of the Solar Ring mission is to deploy six spacecraft, grouped in threepairs, on a sub-AU orbit around the Sun. The two spacecraft in each groupare separated by about $30^\circ$ and every two groups by about $120^\circ$. This configuration with necessaryscience payloads will allow us toestablish three unprecedented capabilities: (1) determine the photospheric vector magneticfield with unambiguity, (2) provide $360$-degree maps of the Sun and the inner heliosphere routinely, and (3) resolve the solar wind structuresat multiple scales and multiple longitudes. With these capabilities, the Solar Ring mission aims to addressthe origin of solar cycle, the origin of solar eruptions, the origin ofsolar wind structures and the origin of severe space weather events. The successful accomplishment of the missionwill advance our understanding of the star and the space environment that hold our life and enhance our capability ofexpanding the next new territory of human.


This work was supported by the Strategic Priority Program of CAS (Grant Nos. XDB41000000 and XDA15017300), the National Natural Science Foundation of China (NSFC) (Grant No. 41842037). WANG YuMing, SHEN ChengLong, GUO JingNan, ZHANG QuanHao, LIU Kai, LI XiaoLei, LIU Rui and WANG Shui are also supported by the CAS Key Research Program of Frontier Sciences (Grant No. QYZDB-SSW-DQC015), and the NSFC (Grant Nos. 41774178, 41761134088, 41750110481 and 11925302), JI HaiSheng by the NSFC (Grant No. 11790302), and Xia LiDong and Huang ZhengHua by the NSFC (Grant No. 41627806). We thank Dr. J. Zhao from Stanford University for reading the manuscript and providing suggestions.


[1] Hudson H S, Bougeret J L, Burkepile J. Coronal Mass Ejections: Overview of Observations. Space Sci Rev, 2006, 123: 13-30 CrossRef ADS Google Scholar

[2] Yashiro S. A catalog of white light coronal mass ejections observed by the SOHO spacecraft. J Geophys Res, 2004, 109: A07105 CrossRef ADS Google Scholar

[3] Dikpati M, Charbonneau P. A Babcock-Leighton Flux Transport Dynamo with Solar-like Differential Rotation. Astrophys J, 1999, 518: 508-520 CrossRef ADS Google Scholar

[4] Reid G C. Solar variability and its implications for the human environment. J Atmos Sol-Terrestrial Phys, 1999, 61: 3-14 CrossRef Google Scholar

[5] Lean J, Rind D. Evaluating sun?Cclimate relationships since the Little Ice Age. J Atmos Sol-Terrestrial Phys, 1999, 61: 25-36 CrossRef Google Scholar

[6] Nandy D, Mu?oz-Jaramillo A, Martens P C H. The unusual minimum of sunspot cycle 23 caused by meridional plasma flow variations. Nature, 2011, 471: 80-82 CrossRef PubMed ADS arXiv Google Scholar

[7] Schrijver C J, Livingston W C, Woods T N. The minimal solar activity in 2008-2009 and its implications for long-term climate modeling. Geophys Res Lett, 2011, 38: L06701 CrossRef ADS Google Scholar

[8] McComas D J, Angold N, Elliott H A. Weakest Solar Wind of the Space Age and the Current “Mini” Solar Maximum. Astrophys J, 2013, 779: 2 CrossRef ADS Google Scholar

[9] Feulner G, Rahmstorf S. On the effect of a new grand minimum of solar activity on the future climate on Earth. Geophys Res Lett, 2010, 37: L05707 CrossRef ADS Google Scholar

[10] Domingo V, Fleck B, Poland A I. SOHO: The Solar and Heliospheric Observatory. Space Sci Rev, 1995, 72: 81-84 CrossRef ADS Google Scholar

[11] Handy B N, Acton L W, Kankelborg C C. Sol Phys, 1999, 187: 229-260 CrossRef Google Scholar

[12] Ogawara Y, Takano T, Kato T. The SOLAR-A Mission - An Overview. Sol Phys, 1991, 136: 1-16 CrossRef ADS Google Scholar

[13] Pesnell W D, Thompson B J, Chamberlin P C. The Solar Dynamics Observatory (SDO). Sol Phys, 2012, 275: 3-15 CrossRef ADS Google Scholar

[14] Kosugi T, Matsuzaki K, Sakao T. The Hinode (Solar-B) Mission: An Overview. Sol Phys, 2007, 243: 3-17 CrossRef ADS Google Scholar

[15] Kaiser M L, Kucera T A, Davila J M. The STEREO Mission: An Introduction. Space Sci Rev, 2008, 136: 5-16 CrossRef ADS Google Scholar

[16] Müller D, Marsden R G, St. Cyr O C. Solar Orbiter . Exploring the Sun-Heliosphere Connection. Sol Phys, 2013, 285: 25-70 CrossRef ADS arXiv Google Scholar

[17] Ogilvie K W, Parks G K. First results from WIND spacecraft: An introduction. Geophys Res Lett, 1996, 23: 1179-1181 CrossRef ADS Google Scholar

[18] Stone R G, Frandsen A M, Mewaldt R A, et al. The advanced composition explorer. Space Sci Rev 1998, 86: 1--22. Google Scholar

[19] NOAA. Dscovr: Deep space climate observatory. https://www.nesdis.noaa.gov/content/dscovr-deep-space-climate-observatory 2015. Google Scholar

[20] Winkler W. HELIOS assessment and mission results. Acta Astronaut, 1976, 3: 435-447 CrossRef Google Scholar

[21] Wenzel K P, Marsden R G, Page D E, et al. The Ulysses mission. Astron Astrophys Suppl 1992, 92: 207. Google Scholar

[22] Fox N J, Velli M C, Bale S D. The Solar Probe Plus Mission: Humanity's First Visit to Our Star. Space Sci Rev, 2016, 204: 7-48 CrossRef ADS Google Scholar

[23] Solomon S C, McNutt Jr. R L, Gold R E. MESSENGER Mission Overview. Space Sci Rev, 2007, 131: 3-39 CrossRef ADS Google Scholar

[24] Svedhem H, Titov D V, McCoy D. Venus ExpressThe first European mission to Venus. Planet Space Sci, 2007, 55: 1636-1652 CrossRef ADS Google Scholar

[25] Schmidt R. Mars ExpressESA's first mission to planet Mars. Acta Astronaut, 2003, 52: 197-202 CrossRef Google Scholar

[26] Jakosky B M, Lin R P, Grebowsky J M. The Mars Atmosphere and Volatile Evolution ( MAVEN) Mission. Space Sci Rev, 2015, 195: 3-48 CrossRef ADS Google Scholar

[27] Yamin Wang, Xin Chen, Pengcheng Wang, Chengbo Qiu, Yuming Wang, and Yonghe Zhang. Concept of the solar ring mission: Preliminary design and mission profile. Sci. China Tech. Sci. submitted, 2020. Google Scholar

[28] Allen Gary G, Hagyard M J. Transformation of vector magnetograms and the problems associated with the effects of perspective and the azimuthal ambiguity. Sol Phys, 1990, 126: 21-36 CrossRef Google Scholar

[29] Schou J, Scherrer P H, Bush R I. Design and Ground Calibration of the Helioseismic and Magnetic Imager (HMI) Instrument on the Solar Dynamics Observatory (SDO). Sol Phys, 2012, 275: 229-259 CrossRef ADS Google Scholar

[30] Liu L, Wang Y, Wang J. Why is a Flare-rich Active Region CME-poor?. Astrophys J, 2016, 826: 119 CrossRef ADS arXiv Google Scholar

[31] Jin C L, Wang J X, Xie Z X. Solar Intranetwork Magnetic Elements: Intrinsically Weak or Strong?. Sol Phys, 2012, 280: 51-67 CrossRef ADS Google Scholar

[32] Wiegelmann T, Sakurai T. Solar Force-free Magnetic Fields. Living Rev Sol Phys, 2012, 9: 5 CrossRef ADS arXiv Google Scholar

[33] Wiegelmann T. Nonlinear force-free modeling of the solar coronal magnetic field. J Geophys Res, 2008, 113: A03S02 CrossRef ADS arXiv Google Scholar

[34] Ya Wang, Yingna Su, Yuming Wang, Yuanyong Deng, Rui Liu, Jianping Li, and Haisheng Ji. Mapping global vector magnetic field of the Sun's photosphere without 180-degree ambiguity. Sci. China Phys. Mech. & Astron. in preparatoin, 2020. Google Scholar

[35] Schrijver C J, Title A M. Long-range magnetic couplings between solar flares and coronal mass ejections observed by SDO and STEREO. J Geophys Res, 2011, 116: A04108 CrossRef ADS Google Scholar

[36] Christensen-Dalsgaard J, Dappen W, Ajukov S V. The Current State of Solar Modeling. Science, 1996, 272: 1286-1292 CrossRef PubMed ADS Google Scholar

[37] Scherrer P H, Bogart R S, Bush R I. The Solar Oscillations Investigation - Michelson Doppler Imager. Sol Phys, 1995, 162: 129-188 CrossRef ADS Google Scholar

[38] Harvey J W, Hill F, Hubbard R P. The Global Oscillation Network Group (GONG) Project. Science, 1996, 272: 1284-1286 CrossRef PubMed ADS Google Scholar

[39] Thompson M J, Toomre J, Anderson E R. Differential Rotation and Dynamics of the Solar Interior. Science, 1996, 272: 1300-1305 CrossRef PubMed ADS Google Scholar

[40] Howe R, Christensen-Dalsgaard J, Hill F. Deeply Penetrating Banded Zonal Flows in the Solar Convection Zone. Astrophys J, 2000, 533: L163-L166 CrossRef PubMed ADS arXiv Google Scholar

[41] Zhao J, Bogart R S, Kosovichev A G. Detection of Equatorward Meridional Flow and Evidence of Double-cell Meridional Circulation inside the Sun. Astrophys J, 2013, 774: L29 CrossRef ADS arXiv Google Scholar

[42] Miesch M S, Brown B P. Convective Babcock-Leighton Dynamo Models. Astrophys J, 2012, 746: L26 CrossRef ADS arXiv Google Scholar

[43] G. M. Simnett and H. S. Hudson. The evolution of a rapidly-expanding active region loop into a trans-equatorial coronal mass ejection. In: Prcoceedings of the Correlated Phenomena at the Sun, in the Heliosphere and in Geospace Proc. 31st ESLAB Symp. (ESA SP-415). Netherlands, 1997. 437--441. Google Scholar

[44] Moon Y J, Choe G S, Wang H. Sympathetic Coronal Mass Ejections. Astrophys J, 2003, 588: 1176-1182 CrossRef ADS Google Scholar

[45] Zhou G, Wang J, Wang Y. Quasi-Simultaneous Flux Emergence in the Events of October November 2003. Sol Phys, 2007, 244: 13-24 CrossRef ADS Google Scholar

[46] Zhang Y, Wang J, Attrill G D R. Coronal Magnetic Connectivity and EUV Dimmings. Sol Phys, 2007, 241: 329-349 CrossRef ADS Google Scholar

[47] Pevtsov A A. Transequatorial Loops in the Solar Corona. Astrophys J, 2000, 531: 553-560 CrossRef ADS Google Scholar

[48] Heinemann S G, Temmer M, Hofmeister S J. Three-phase Evolution of a Coronal Hole. I. 360 Remote Sensing and In Situ Observations. Astrophys J, 2018, 861: 151 CrossRef ADS arXiv Google Scholar

[49] Liu Y, Hoeksema J T, Scherrer P H. Comparison of Line-of-Sight Magnetograms Taken by the Solar Dynamics Observatory/Helioseismic and Magnetic Imager and Solar and Heliospheric Observatory/Michelson Doppler Imager. Sol Phys, 2012, 279: 295-316 CrossRef ADS Google Scholar

[50] Xiaolei Li, Yuming Wang, Rui Liu, Chenglong Shen, Quanhao Zhang, Shaoyu Lv, Bin Zhuang, Fang Shen, Jiajia Liu, and Yutian Chi. Reconstructing solar wind inhomogeneous structures from stereoscopic observations in white-light: Solar wind transients in 3d. J. Geophys. Res.: Space Phys. submitted, 2020. Google Scholar

[51] Aschwanden M J, Wülser J P, Nitta N V. First Three-Dimensional Reconstructions of Coronal Loops with the STEREO A and B Spacecraft. I. Geometry. Astrophys J, 2008, 679: 827-842 CrossRef ADS Google Scholar

[52] Liu J J, Wang Y M, Liu R, et al. When and how does a prominence-like jet gain kinetic energy? Astrophys J 2014, 782: 94. Google Scholar

[53] Kwon R Y, Chae J, Zhang J. Stereoscopic Determination of Heights of Extreme Ultraviolet Bright Points Using Data Taken by SECCHI/EUVI Aboard STEREO. Astrophys J, 2010, 714: 130-137 CrossRef ADS Google Scholar

[54] Robbrecht E, Patsourakos S, Vourlidas A. No Trace Left Behind: STEREO Observation of a Coronal Mass Ejection Without Low Coronal Signatures. Astrophys J, 2009, 701: 283-291 CrossRef ADS arXiv Google Scholar

[55] Wang Y, Chen C, Gui B. Statistical study of coronal mass ejection source locations: Understanding CMEs viewed in coronagraphs. J Geophys Res, 2011, 116: A04104 CrossRef ADS arXiv Google Scholar

[56] Thernisien A F R, Howard R A, Vourlidas A. Modeling of Flux Rope Coronal Mass Ejections. Astrophys J, 2006, 652: 763-773 CrossRef ADS Google Scholar

[57] Sheeley N R, Lee D D H, Casto K P. The Structure of Streamer Blobs. Astrophys J, 2009, 694: 1471-1480 CrossRef ADS Google Scholar

[58] Lugaz N, Vourlidas A, Roussev I I. Deriving the radial distances of wide coronal mass ejections from elongation measurements in the heliosphere - application to CME-CME interaction. Ann Geophys, 2009, 27: 3479-3488 CrossRef ADS arXiv Google Scholar

[59] Feng L, Inhester B, Mierla M. Comparisons of CME Morphological Characteristics Derived from Five 3D Reconstruction Methods. Sol Phys, 2013, 282: 221-238 CrossRef ADS arXiv Google Scholar

[60] Xiaolei Li, Yuming Wang, Rui Liu, Chenglong Shen, Quanhao Zhang, Bin Zhuang, Jiajia Liu, and Yutian Chi. Reconstructing solar wind inhomogeneous structures from stereoscopic observations in white-light: Small transients along the Sun-Earth line. J. Geophys. Res.: Space Phys. 2018, 123: 7257--7270. Google Scholar

[61] Wang Y, Zhang Q, Liu J. On the propagation of a geoeffective coronal mass ejection during 15-17 March 2015. J Geophys Res Space Phys, 2016, 121: 7423-7434 CrossRef ADS arXiv Google Scholar

[62] Shaoyu Lyu, Xiaolei Li, and Yuming Wang. Optimal stereoscopic angle for reconstructing solar wind inhomogeneous structures. Sci. China Phys. Mech. & Astron. submitted, 2020. Google Scholar

[63] Wang Y, Shen C, Wang S. Deflection of coronal mass ejection in the interplanetary medium. Sol Phys, 2004, 222: 329-343 CrossRef Google Scholar

[64] Riley P, Crooker N U. Kinematic Treatment of Coronal Mass Ejection Evolution in the Solar Wind. Astrophys J, 2004, 600: 1035-1042 CrossRef ADS Google Scholar

[65] Manchester IV W, Gombosi T, DeZeeuw D. Eruption of a Buoyantly Emerging Magnetic Flux Rope. Astrophys J, 2004, 610: 588-596 CrossRef ADS Google Scholar

[66] Wang Y, Wang B, Shen C. Deflected propagation of a coronal mass ejection from the corona to interplanetary space. J Geophys Res Space Phys, 2014, 119: 5117-5132 CrossRef ADS arXiv Google Scholar

[67] Kay C, Opher M. The Heliocentric Distance where the Deflections and Rotations of Solar Coronal Mass Ejections Occur. Astrophys J, 2015, 811: L36 CrossRef ADS arXiv Google Scholar

[68] Gopalswamy N, Lara A, Lepping R P. Interplanetary acceleration of coronal mass ejections. Geophys Res Lett, 2000, 27: 145-148 CrossRef ADS Google Scholar

[69] Vr?nak B, Vrbanec D, ?alogovi? J. Dynamics of coronal mass ejections. Astron Astrophys, 2008, 490: 811-815 CrossRef Google Scholar

[70] Vr?nak B, ?ic T, Vrbanec D. Propagation of Interplanetary Coronal Mass Ejections: The Drag-Based Model. Sol Phys, 2013, 285: 295-315 CrossRef ADS Google Scholar

[71] Chenglong Shen, Yuming Wang, Zonghao Pan, Bin Miao, Pinzhong Ye, and S. Wang. Full-halo coronal mass ejections: Arrival at the Earth J. Geophys. Res.: Space Phys. 2014, 119: 5107--5116. Google Scholar

[72] Dasso S, Mandrini C H, Démoulin P. A new model-independent method to compute magnetic helicity in magnetic clouds. Astron Astrophys, 2006, 455: 349-359 CrossRef Google Scholar

[73] Ruffenach A, Lavraud B, Farrugia C J. Statistical study of magnetic cloud erosion by magnetic reconnection. J Geophys Res Space Phys, 2015, 120: 43-60 CrossRef ADS Google Scholar

[74] Yuming Wang, Chenglong Shen, Rui Liu, Mengjiao Xu, Qiang Hu, Jiajia Liu, Jingnan Guo, Xiaolei Li, , and Tielong Zhang. Understanding the twist distribution inside magnetic flux ropes by anatomizing an interplanetary magnetic cloud. J. Geophys. Res.: Space Phys. 2018, 123: 3238 -3261. Google Scholar

[75] Shen C, Wang Y, Wang S. Super-elastic collision of large-scale magnetized plasmoids in the heliosphere. Nat Phys, 2012, 8: 923-928 CrossRef ADS arXiv Google Scholar

[76] N. Lugaz, C. J. Farrugia, J. A. Davies, C. Mostl, C. J. Davis, I. I. Roussev, and M. Temmer. The deflection of the two interacting coronal mass ejections of 2010 may 23-24 as revealed by combined in site measurements and heliospheric imaging. Astrophys J 2012, 759: 68. Google Scholar

[77] Manuela Temmer, A. M. Veronig, V. Peinhart, and Bojan Vršnak. Asymmetry in the CME-CME interaction process for the events from 2011 February 14--15. Astrophys J 2014, 785: 85. Google Scholar

[78] Mishra W, Wang Y, Srivastava N. Assessing the Nature of Collisions of Coronal Mass Ejections in the Inner Heliosphere. Astrophys J Suppl Ser, 2017, 232: 5 CrossRef ADS arXiv Google Scholar

[79] D. E. Larson, R. P. Lin, J. M. McTiernan, J. P. McFadden, R. E. Ergun, M. McCarthy, H. Rème, T. R. Sanderson, M. Kaiser, R. P. Lepping, and J. Mazur. Tracing the topology of the october 18-20, 1995, magnetic cloud with $\sim0.1-10^2$ kev electrons. Geophys. Res. Lett. 1997, 24: 1911--1914. Google Scholar

[80] Wang Y, Zhou Z, Shen C. Investigating plasma motion of magnetic clouds at 1 AU through a velocity-modified cylindrical force-free flux rope model. J Geophys Res Space Phys, 2015, 120: 1543-1565 CrossRef ADS arXiv Google Scholar

[81] Hassler D M, Zeitlin C, Wimmer-Schweingruber R F. The Radiation Assessment Detector (RAD) Investigation. Space Sci Rev, 2012, 170: 503-558 CrossRef ADS Google Scholar

[82] Jingnan Guo, Mateja Dumbović, Robert F. Wimmer-Schweingruber, Manuela Temmer, Henning Lohf, Yuming Wang, Astrid Veronig, Donald M. Hassler, Leila M. Mays, Cary Zeitlin, Bent Ehresmann, Olivier Witasse, Johan L. Freiherr von Forstner Bernd Heber, Mats Holmström, and Arik Posner. Modeling the evolution and propagation of 10 September 2017 CMEs and SEPs arriving at Mars constrained by remote sensing and in situ measurement. Space Weather 2018, 16: 1156--1169. Google Scholar

[83] Wang Y, Zhuang B, Hu Q. On the twists of interplanetary magnetic flux ropes observed at 1 AU. J Geophys Res Space Phys, 2016, 121: 9316-9339 CrossRef ADS arXiv Google Scholar

[84] Démoulin P, Janvier M, Dasso S. Magnetic Flux and Helicity of Magnetic Clouds. Sol Phys, 2016, 291: 531-557 CrossRef ADS arXiv Google Scholar

[85] Owens M J. Do the Legs of Magnetic Clouds Contain Twisted Flux-rope Magnetic Fields?. Astrophys J, 2016, 818: 197 CrossRef ADS Google Scholar

[86] Zhao A, Wang Y, Chi Y. Main Cause of the Poloidal Plasma Motion Inside a Magnetic Cloud Inferred from Multiple-Spacecraft Observations. Sol Phys, 2017, 292: 58 CrossRef ADS Google Scholar

[87] Owens M J, Lockwood M, Barnard L A. Coronal mass ejections are not coherent magnetohydrodynamic structures. Sci Rep, 2017, 7: 4152 CrossRef PubMed ADS Google Scholar

[88] Desai M, Giacalone J. Large gradual solar energetic particle events. Living Rev Sol Phys, 2016, 13: 3 CrossRef ADS Google Scholar

[89] Cane H V, Reames D V, von Rosenvinge T T. The role of interplanetary shocks in the longitude distribution of solar energetic particles. J Geophys Res, 1988, 93: 9555-9567 CrossRef ADS Google Scholar

[90] Wang Y, Zhang J, Shen C. An analytical model probing the internal state of coronal mass ejections based on observations of their expansions and propagations. J Geophys Res, 2009, 114: A10104 CrossRef ADS arXiv Google Scholar

[91] Mishra W, Wang Y. Modeling the Thermodynamic Evolution of Coronal Mass Ejections Using Their Kinematics. Astrophys J, 2018, 865: 50 CrossRef ADS arXiv Google Scholar

[92] Wang Y, Cao H, Chen J. Solar Limb Prominence Catcher and Tracker (SLIPCAT): An Automated System and its Preliminary Statistical Results. Astrophys J, 2010, 717: 973-986 CrossRef ADS arXiv Google Scholar

[93] Gosling J T. Magnetic Reconnection in the Solar Wind. Space Sci Rev, 2012, 172: 187-200 CrossRef ADS Google Scholar

[94] Shen F, Shen C, Wang Y. Could the collision of CMEs in the heliosphere be super-elastic? Validation through three-dimensional simulations. Geophys Res Lett, 2013, 40: 1457-1461 CrossRef ADS arXiv Google Scholar

[95] Reiner M J, Stone R G. A New Method for Reconstructing Type-Iii Trajectories. Sol Phys, 1986, 106: 397-401 CrossRef ADS Google Scholar

[96] Krupar V, Maksimovic M, Santolik O. Statistical Survey of Type III Radio Bursts at Long Wavelengths Observed by the Solar TErrestrial RElations Observatory (STEREO)/ Waves Instruments: Goniopolarimetric Properties and Radio Source Locations. Sol Phys, 2014, 289: 4633-4652 CrossRef ADS arXiv Google Scholar

[97] J. Magdalenić C. Marqué V. Krupar, M. Mierla, A. N. Zhukov, L. Rodriguez, M. Maksimović and B. Cecconi. Tracking the CME-driven shock wave on 2012 March 5 and radio triangulation of associated radio emission. Astrophys J 2014, 791: 115. Google Scholar

[98] Zhang P, Wang C, Ye L. Forward Modeling of the Type III Radio Burst Exciter. Sol Phys, 2019, 294: 62 CrossRef ADS arXiv Google Scholar

[99] Cecconi B, Bonnin X, Hoang S. STEREO/Waves Goniopolarimetry. Space Sci Rev, 2008, 136: 549-563 CrossRef ADS Google Scholar

[100] Robert J. Leamon, Charles W. Smith, Norman F. Ness, William H. Matthaeus, and Hung K. Wong. Observational constraints on the dynamics of the interplanetary magnetic field dissipation range. 103 1998, 103: 4775--4788. Google Scholar

[101] Hu R X, Shan X, Yuan G Y. A low-energy ion spectrometer with half-space entrance for three-axis stabilized spacecraft. Sci China Technol Sci, 2019, 62: 1015-1027 CrossRef ADS Google Scholar

[102] Malandraki O E, Lario D, Lanzerotti L J. October/November 2003 interplanetary coronal mass ejections: ACE/EPAM solar energetic particle observations. J Geophys Res, 2005, 110: A09S06 CrossRef ADS Google Scholar

[103] Wu W, Chen M, Zhang Z. Overview of deep space laser communication. Sci China Inf Sci, 2018, 61: 040301 CrossRef Google Scholar

  • Figure 1

    (a) Schematic diagram of the Solar Ring mission. The six pink dots roughly denote the positions of the six spacecraft, which run on a sub-AU orbit. (b)A sketch map illustrates the stereoscopic angles of the spacecraft and their coverage in the longitude.

  • Figure 2

    (a)The HMI vector magnetogram of the active region NOAA 12192. The gray color scales the longitudinal component of the magnetic field, and the red/blue arrows denote the transversal component. (b), (c)Scatter plots of the longitudinal and transversal components of the magnetic field in the central region marked by the cyan box in (a). (d), (e) The same scatter plots, but in the region near the edge marked by the yellow box in (a). The horizontal axes in (b)–(e) mark the serial numbers of the data points in the data set, having no physical meaning. The magnetic field within the active region is highly structured, but that in the quiescent region is more close to noise. The horizontal pink lines denote the 90-percentile of the magnetic field strength, suggesting the noise level.

  • Figure 3

    A cartoon of the local photospheric region, illustrating some issues affecting the accuracy of the inversion of magnetic field from dual perspectives. The black arrows $a$ and $b$ indicate the observational paths. The photosphere is a non-uniform layer with different optical depths.

  • Figure 4

    (a)Three-color composite EUV image combined from SDO/AIA 211 Å, 193 Å, and 171 Å channels on 1 August 2010. Coronal magnetic field lines extrapolated using a potential field source surface (PFSS) model are superimposed, showing the magnetic connections among different regions. Letters denote the locations of the eruptive events during 1–2 August 2010. (b)GOES 1–8 Å light curve with the same denoted letters. Adapted from ref. [34].

  • Figure 5

    (a) The running-difference images of the heliosphere taken by HI-1 cameras on board the STEREO A and B spacecraft at 21:29 UT on 3 April 2010. A CME was captured. (b) The correlation coefficient (cc) map of the heliosphere at the same time, inferred from the HI-1 images through CORAR method. The CME is reconstructed in the high cc region. The yellow, cyan, orange and blue balls denote the Sun, Mercury, Venus and Earth. Adapted from the paper [59].

  • Figure 6

    A cartoon showing the large-scale magnetic flux rope, or called magnetic cloud, in the heliosphere. The magnetic field lines are twisted in the magnetic cloud as indicated by the color-coded lines. The reconnection site implies the erosion process. A shock exists if the magnetic cloud propagates fast. Adapted from ref. [72].

  • Figure 7

    The fluxes of energetic particles recorded by (a GOES at Earth, (b Radiation Assessment Detector (RAD [80]) at Mars and (c STEREO A during 10–16 September 2017. The pink region indicates the shock (and CME) arrival, and the cyan region the stream interaction region. The positions of the Earth, Mars and STEREO A on 10 September 2017 are plotted too. A complex solar eruption caused the enhancement of the fluxes in a wide range. Adapted from ref. [81].

  • Figure 8

    The elliptical orbits (cyan, light green and pink) of the three groups of the spacecraft with the perihelion of $0.75$ AU and the aphelion of $1$ AU. In this scheme, the separation angle among the three groups oscillates around $120^\circ$ and the angle between the spacecraft in each group oscillates around $30^\circ$.

  • Figure 9

    The data transmission rate as a function of the distance between the spacecraft and Earth. Different lines show the rate for the telescope with different size and different power.

  • Table 1   Science objectives and required measurements
    magnetic Solar White- Solar Solar
    Science Scientific questions Strategy field & EUV light Radio wind wind Energetic
    objectives global images images emissions magnetic plasma particles
    Doppler field
    Originof solarcycle How does the global magnetic flux emerge, transport and dissipate? Trace the global magnetic fluxes at multiple scales. $\surd$
    What is the solar internal structure? Analyze the global oscillation modes. $\surd$
    Originof solareruptions How is the energy accumulated and released, and how is an eruption triggered? Trace the evolution of source region and combine measured magnetic field, radio emissions and energetic particles to estimate some key parameters, e.g., the magnetic energy and helicity, and key processes. $\surd$ $\surd$ $\surd$ $\surd$
    How are the coronal structures reconstructed, and what kind of structures are formed and ejected into heliosphere? Extrapolate coronal field and compare with observed coronal plasma structures in EUV, compare erupted signatures in EUV and white-light images. $\surd$ $\surd$ $\surd$
    Origin of solar wind structures Where does an solar wind structure come from? What's its topology and magnetic connection with the Sun? How does a solar wind structure evolve in the heliosphere in terms of its propagation direction, velocity, topology, etc? Use white-light images from multiple perspectives to recognize and reconstruct solar wind structures in interplanetary space and trace their evolution. Associate the imaging data of solar wind structures to em in-situ data at 1 AU to confirm their properties, and trace back to the Sun to obtain the properties of their sources. $\surd$ $\surd$ $\surd$ $\surd$ $\surd$ $\surd$ $\surd$
    Origin of severe space weather events What are the primary factors causing major geomagnetic storms and/or solar energetic particle events? Investigate em in-situ data, including magnetic field, solar wind plasma and energetic particles, at different longitudes to assess the effects of various factors on the space weather. $\surd$ $\surd$ $\surd$ $\surd$
    What are the properties of the source regions of the drivers of severe space weather? How can we make an accurate forecast of the space weather effects of solar eruptions? Use imaging data of the heliosphere and the Sun to identify the source regions of the space-weather-effecting solar wind structures and to study the relationship between the solar eruptions and space weather events. $\surd$ $\surd$ $\surd$ $\surd$ $\surd$ $\surd$ $\surd$
  • Table 2   Main tasks and preliminary technical specifications of payloads (to be continued)
    Payloads Main tasks Preliminary technical specifications
    Spectral imager for magnetic field and Measure photospheric vector magnetic field Mass: $\leq30$ kg
    helioseismology (SIMS) to learn the global transportation of magnetic Power consumption: $\leq40$ W
    flux; measure global Doppler velocity to Data rate: $\leq30$ Mbps (@peak time)
    learn the global oscillations. Field of view: $32'\times32'$ (@1 AU)
    Effective pixels: no less than $4096\times4096$
    Spectral resolution: better than $0.04~\AA$
    Temporal resolution of longitudinal component: $1$ min, $1$ h
    Temporal resolution of transversal component: $2$ min, $1$ h
    Multi-band imager for EUV emissions Obtain the global EUV images of solar Mass: $\leq30$ kg
    (MIE) disk at three wavelength bands, Power consumption: $\leq60$ W
    corresponding to relatively cool, warm Data rate: $\leq21$ Mbps (@peak time)
    and hot temperatures, respectively, to Field of view: $42'\times42'$ (@1 AU)
    learn the morphology, topology, Effective pixels: no less than $4096\times4096$
    connectivity and emission measure of Wavelength bands: $304~\AA$, $171~\AA$, $131~\AA$
    various plasma structures. Temporal resolution: $10$ s, $1$ min, $1$ h
    Wide-angle coronagraph (WAC) Obtain white-light images of the solar Mass: $\leq25$ kg
    wind structures traveling through the Power consumption: $\leq40$ W
    outer corona and inner heliosphere to Data rate: $<1$ Mbps (@peak time)
    learn their kinematic properties; get Field of view: $\pm12^\circ$
    total brightness and the variations to Occulting disk: $\pm2^\circ$
    learn the density distribution in 3D. Effective pixels: no less than $4096\times4096$
    Temporal resolution: $1$ min, $1$ h
    Radio investigator (WAVES) Measure the electric field intensity Mass: $\leq15$ kg
    induced by the radio emissions from Power consumption: $\leq16$ W
    the Sun to recognize the radio bursts Data rate: $0.5$ kbps
    and get the location of the driving Frequency range: $5$ kHz–$30$ MHz
    source and its kinematic properties. Frequency channels: no less than 160
    Temporal resolution: better than $30$ s
    GP mode: $0.2$ s for each channel/antenna configuration
    Flux-gate magnetometer (FGM) Measure the em in-situ magnetic field at 1 Mass: $\leq2$ kg
    AU to learn the variations during solar Power consumption: $\leq3$ W
    wind structures and the distribution in Data rate: $\leq8$ kbps
    longitude. Maximum measuring range: $\pm65000$ nT
    Dynamic measurement range: $2000$ nT
    Resolution: better than $0.01$ nT
    Noise level: better than $0.01$ nT/$\sqrt{\text{Hz}}$
    Zero drift: better than $0.01$ nT/$^\circ~C$
    Sampling rate: $0.1$ Hz, $128$ Hz
    Solar wind plasma analyzer (SPA) Measure the em in-situ solar wind plasma Mass: $\leq7$ kg
    at 1 AU; obtain the velocity, density, Power consumption: $\leq~20$ W
    temperature and composition of the Data rate: $\leq50$ kbps
    solar wind to learn the variations Field of view: $180^\circ$ (azimuthal angle) $\times$ $\pm45^\circ$ (polar angle)
    during solar wind structures and the Angular resolution: better than $12^\circ$ (azimuthal) $\times$ $15^\circ$ (polar)
    distribution in longitude. Temporal resolution: 4–64 s (adjustable)
    $\bullet$ Energy range: 0.1–25 keV
    $\bullet$ Energy resolution: better than 12%
    $\bullet$ Energy channels: no less than 64
    $\bullet$ Mass range: 0–60 amu
    $\bullet$ Mass resolution: better than 18%
    $\bullet$ Energy range: 0.05–10 keV
    $\bullet$ Energy resolution: better than 12%
    $\bullet$ Energy channels: no less than 64
    High-energy particle detector (HiPD) Measure energetic particles in multiple Mass: $\leq1$ kg
    energies to obtain the intensity and Power consumption: $\leq~1$ W
    spectrum of a solar energetic particle Data rate: $\leq1$ kbps
    event and to learn its driver and the Field of view: $55^\circ$ cone
    distribution in longitude. Mass range: 0–60 amu, electrons
    Energy range of
    $\bullet$ Electrons: 0.5–20 MeV
    $\bullet$ Protons: 10–100 MeV
    $\bullet$ Heavy ions: 20–200 MeV/nuc
    Total Mass: $\leq110$ kg, power: $\leq180$ W, data rate: $\leq52.06$ Mbps

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