Иркутск, Россия
Иркутск, Россия
Иркутск, Россия
Иркутск, Россия
We analyze the presence of a microwave neutral-line-associated source (NLS) in a super-active region NOAA 12673, which produced a number of geo-effective events in September 2017. To estimate the NLS position, we use data from the Siberian Radioheliograph in a range 4–8 GHz and from the Nobeyama Radioheliograph at 17 GHz. Calculation of the coronal magnetic field in a non-linear force-free approximation has revealed an extended structure consisting of interconnected magnetic flux ropes, located practically along the entire length of the main polarity separation line of the photospheric magnetic field. NLS is projected into the region of the strongest horizontal magnetic field, where the main energy of this structure is concentrated. During each X-class flare, the active region lost magnetic helicity and became a CME source.
solar active regions, magnetic fields, microwave emission, solar flare forecast
1. Abramov-Maximov V.E., Borovik V.N., Opeikina L.V., Tlatov A.G. Dynamics of microwave sources associated with the neutral line and the magnetic-field parameters of sunspots as a factor in predicting large flares. Solar Phys. 2015, vol. 290, iss. 1, pp. 53-77. DOI:https://doi.org/10.1007/s11207-014-0605-8.
2. Abramov-Maximov V.E., Borovik V.N., Opeikina L.V., Tlatov A.G. Evolution of solar active region 12673 by RATAN-600 and SDO data. Trudy XXII Vserossiiskoi ezhegodnoi konferentsii po fizike Solntsa “Solnechnaya i solnechno-zemnaya fizika” [Proc. XXII All-Russian Annual Conference on Solar Physics “Solar and Solar-Terrestrial Physics”]. Russia, St. Petersburg, 2018, pp. 15-18. DOI:https://doi.org/10.31725/0552-5829-2018-15-18. (In Russian).
3. Akhmedov S.B., Borovik V.N., Gelfreikh G.B., Bogod V.M., Korzhavin A.N., Petrov Z.E., Dikij V.N., Lang K.R., Willson R.F. Structure of a solar active region from RATAN 600 and Very Large Array observations. Astrophys. J. 1986, vol. 301, pp. 460-464.
4. Altyntsev A.T., Lesovoi S.V., Globa M.V., Gubin A.V., Kochanov A.A., Grechnev V.V., Ivanov E.F., Kobets V.S., Meshalkina N.S., Muratov A.A., Prosovetsky D.V., Myshyakov I.I., Uralov A.M., Fedotova A.Yu. Multiwave Siberian Radioheliograph. Solar-Terr. Phys. 2020, vol. 6, iss. 2, pp. 30-40. DOI:https://doi.org/10.12737/stp-62202003.
5. Anfinogentov S.A., Stupishin A.G., Mysh’yakov I.I., Fleishman G.D. Record-breaking coronal magnetic field in solar active region 12673. Astrophys. J. Lett. 2019, vol. 880, iss. 2, L29, 5 p. DOI:https://doi.org/10.3847/2041-8213/ab3042.
6. Bakunina I.A., Abramov-Maximov V.E., Osharin A.M. Evolution of the compact microwave inter-sunspot source before strong flare. J. Physics: Conf. Series. 2017, vol. 798, iss. 1, 012041. DOI:https://doi.org/10.1088/1742-6596/798/1/012041.
7. Bogod V.M., Kaltman T.I., Yasnov L.V. On properties of microwave sources located above the neutral line of radial magnetic field. Astrophys. Bull. 2012, vol. 67, iss. 4, pp. 42-437. DOI:https://doi.org/10.1134/S1990341312040062.
8. Borovik V.N., Vatrushin S.M., Korzhavin A.N. Radio characteristics of the active region connected with the proton flare of April 24, 1985 based on observations with RATAN-600. Bull. Spec. Astrophys. Obs. 1989, vol. 28, pp. 123-131.
9. Borovik V.N., Abramov-Maximov V.E., Tlatov A.G., Opeikina L.V., Shramko A.D., Yasnov L.V. Signs of preparing powerful solar flares in September 2017 in microwave emission and magnetic field structure of active region from RATAN-600 and SDO/HMI data. Izуestiya Krymskoi astrofiz. obs. [Bull. of the Crimean Astrophys. Observatory]. 2018. vol. 114, no. 1. pp. 8994. (In Russian).
10. Chiuderi Drago F., Alissandrakis C.E., Hagyard M. Microwave emission above steady and moving sunspots. Solar Phys. 1987, vol. 112, pp. 89-105. DOI:https://doi.org/10.1007/BF00148490.
11. Gelfreikh G.B. The problem of search for current sheets in the solar atmosphere with radio astronomical methods. Fizika solnechnykh vspyshek [The physics of the solar flares]. Moscow. Nauka Publ., 1985, pр. 111117. (In Russian).
12. Grechnev V.V., Lesovoi S.V., Smolkov G.Ya., Krissinel B.B., Zandanov V.G., Altyntsev A.T., et al. The Siberian Solar Radio Telescope: the current state of the instrument, observations, and data. Solar Phys. 2003, vol. 216, iss. 1-2, pp. 239-272. DOI:https://doi.org/10.1023/A:1026153410061.
13. Grechnev V.V., Uralov A.M., Zandanov V.G., Baranov N.Y., Shibasaki K. Observations of prominence eruptions with two radioheliographs, SSRT and NoRH. Publ. Astron. Soc. Japan. 2006, vol. 58, pp. 69-84. DOI:https://doi.org/10.1093/pasj/58.1.69.
14. Hou Y.J., Zhang J., Li T.,Yang S.H., Li X.H. Eruption of a multi-flux-rope system in solar active region 12673 leading to the two largest flares in solar cycle 24. Astron. Astrophys. 2018, vol. 619, A100. DOI:https://doi.org/10.1051/0004-6361/201732530.
15. Inoue S., Shiota D., Bamba Y., Park S.-H. Magnetohydrodynamic modeling of a solar eruption associated with an X9.3 flare observed in the active region 12673. Astrophys. J. 2018, vol. 867, iss. 1, 83. DOI:https://doi.org/10.3847/1538-4357/aae079.
16. Kundu M.R., Alissandrakis C.E. Structure and polarization of active region microwave emission. Solar Phys. 1984, vol. 94, iss. 2, pp. 249-283. DOI:https://doi.org/10.1007/BF00151317.
17. Kundu M.R., Velusamy T. Observation with the VLA of a stationary loop structure on the Sun at 6 centimeter wavelength. Astrophys. J. Lett. 1980, vol. 240, pp. L63-L67. DOI:https://doi.org/10.1086/183324.
18. Kundu M.R., Alissandrakis C.E., Bregman J.D., Hin A.C. 6 centimeter observations of solar active regions with 6" resolution. Astrophys. J. 1977, vol. 213, pp. 278-295. DOI:https://doi.org/10.1086/155155.
19. Kundu M.R., Schmahl E.J., Rao A.P. VLA observations of solar active regions at 6 cm wavelength. Astron. Astrophys. 1981, vol. 94, no. 1, pp. 72-79.
20. Kuznetsov A.A., Keppens R., Xia C. Synthetic radio views of simulated solar flux ropes. Solar Phys. 2016, vol. 291, iss. 3, pp. 823-845. DOI:https://doi.org/10.1007/s11207-016-0865-6.
21. Lee J., White S.M., Gopalswamy N., Kundu M.R. Signatures of coronal currents in microwave images. Solar Phys. 1997, vol. 174, iss. 1/2, pp. 175-190. DOI:https://doi.org/10.1023/A:1004956422669.
22. Lesovoi S.V., Altyntsev A.T., Kochanov A.A., Grechnev V.V., Gubin А.V., Zhdanov D.A., et al. Siberian Radioheliograph: First results. Solar-Terr. Phys. 2017, vol. 3, iss. 1, pp. 3-18. DOI:https://doi.org/10.12737/article_58f96ec60fec52.86165286.
23. Nakajima H., Nishio M., Enome S., Shibasaki K., Takano T., Hanaoka Y., et al. The Nobeyama radioheliograph. Proc. IEEE. 1994, vol. 82, iss. 5, pp. 705-713.
24. Quiñones J.A., Korzhavin A.N., Peterova N.G., Santos J. Observations of the solar eclipse on March 7, 1970 with the polarimeter of the Havana Radio Astronomical Station at 4.5 cm. Solnechnye Dannye [Solar Data]. 1975, no. 3, pp. 87-96. (In Russian).
25. Rudenko I.G., Rudenko G.V., Uralov A.M. Radio source above neutral line in active regions generating long-lasted X-flares. Trudy Vserossiiskoi konferentsii “Mnogovolnovye issledovaniya Solntsa i sovremennye problemy solnechnoi aktivnosti” [Proc. All-Russian Conference “Multiwavelength Investigations of the Sun and Modern Problems of Solar Activity”]. Russia, N. Arkhyz, St. Petersburg, 2007, pp. 462-474. (In Russian).
26. Rudenko G.V., Myshyakov I.I. Analysis of reconstruction methods for nonlinear force-free fields. Solar Phys. 2009, vol. 257, iss. 2, pp. 287-304. DOI:https://doi.org/10.1007/s11207-009-9389-7.
27. Scherrer P.H., Schou J., Bush R.I., Kosovichev A.G., Bogart R.S., Hoeksema J.T., Liu Y., Duvall T.L., Zhao J., Title A.M., et al. The Helioseismic and Magnetic Imager (HMI) investigation for the Solar Dynamics Observatory (SDO). Solar Phys. 2012, vol. 275, pp. 207-227. DOI:https://doi.org/10.1007/s11207-011-9834-2.
28. Smolkov G.Ya., Pistolkors A.A., Treskov T.A., Krissinel B.B., Putilov V.A., Potapov N.N. The Siberian Solar Radio Telescope: Parameters and principle of operation, objectives and results of first observations of spatio-temporal properties of development of active regions and flares. Astrophys. Space Sci. 1986, vol. 119, iss. 1, pp. 1-4. DOI:https://doi.org/10.1007/BF00648801.
29. Strong K.T., Alissandrakis C.E., Kundu M.R. Interpretation of microwave active region structures using SMM soft X-ray observations. Astrophys. J. 1984, vol. 277, pp. 865-873. DOI:https://doi.org/10.1086/161757.
30. Sych R.A., Uralov A.M., Korzhavin A.N. Radio observations of compact solar sources located between sunspots. Solar Phys. 1993, vol. 144, iss. 1, pp. 59-68. DOI:https://doi.org/10.1007/BF00667982.
31. Uralov A.M., Sych R.A., Lubyshev B.I., Nefedyev V.P., Golovko A.A., Korobova Z.B., Alissandrakis C.E., Smartt R.N., Zhang Hongqi. Microwave source above neutral line as a factor of prediction of powerfull X-ray flares. Issledovaniya po geomagnetizmu, aeronomii i fizike Solntsa [Res. on Geomagnetism, Aeronomy and Solar Physics]. Novosibirsk, Nauka Publ., 1996, iss. 104, pp. 23-48. (In Russian).
32. Uralov A.M., Sych R.A., Shchepkina V.L., Zubkova G.N., Smolkov G.Ya. Weakly polarized microwave sources in active regions prior to large X-flares. Solar Phys. 1998, vol. 183, iss. 2, pp. 359-368. DOI:https://doi.org/10.1023/A:1005041324807.
33. Uralov A.M., Nakajima H., Zandanov V.G., Grechnev V.V. Current-sheet-associated radio sources and development of the magnetosphere of an active region revealed from 17 GHz and Yohkoh data. Solar Phys. 2000, vol. 197, iss. 2, pp. 275-312. DOI:https://doi.org/10.1023/A:1026582416968.
34. Uralov A.M., Lesovoi S.V., Zandanov V.G., Grechnev V.V. Dual-filament initiation of a coronal mass ejection: Observations and model. Solar Phys. 2002, vol. 208, iss. 1, pp. 69-90. DOI:https://doi.org/10.1023/A:1019610614255.
35. Uralov A.M., Rudenko G.V., Rudenko I.G. Microwave neutral line associated sources: birth, relation to flares, and projection effect. Bull. Russian Academy of Sciences: Physics. 2006, vol. 70, no. 10, pp. 1688-1691.
36. Uralov A.M., Rudenko G.V., Rudenko I.G. 17 GHz neutral line associated sources: birth, motion, and projection effect. Publ. Astron. Soc. Japan. 2006, vol. 58, p. 21. DOI:https://doi.org/10.1093/pasj/58.1.21.
37. Uralov A.M., Rudenko G.V., Grechnev V.V., Rudenko I.G., Nakajima H., Shibasaki K. Microwave source above neutral line as a source below current sheet. Trudy Vserossiiskoi konferentsii “Mnogovolnovye issledovaniya Solntsa i sovremennye problemy solnechnoi aktivnosti” [Proc. All-Russian Conference “Multiwavelength Investigations of the Sun and Modern Problems of Solar Activity”]. Russia, N. Arkhyz, St. Petersburg, 2007, pp. 484-513. (In Russian).
38. Uralov A.M., Grechnev V.V., Rudenko G.V., Rudenko I.G., Nakajima H. Microwave neutral line associated source and a current sheet. Solar Phys. 2008, vol. 249, pp. 315-335. DOI:https://doi.org/10.1007/s11207-008-9183-y.
39. van Tend W., Kuperus M. The development of coronal electric current systems in active regions and their relation to filaments and flares. Solar Phys. 1978, vol. 59, iss. 1, pp. 115-127. DOI:https://doi.org/10.1007/BF00154935.
40. Vatrushin S.M., Korzhavin A.N. Fizika solnechnoi plazmy [The physics of the solar plasma]. Moscow, Nauka Publ., 1989, p. 100.
41. Verma M. The origin of two X-class flares in active region NOAA 12673. Shear flows and head-on collision of new and preexisting flux. Astron. Astrophys. 2018, vol. 612, A101, 7 p. DOI:https://doi.org/10.1051/0004-6361/201732214.
42. Wang H., Yurchyshyn V., Liu C., Ahn K., Toriumi S., Cao W. Strong transverse photosphere magnetic fields and twist in light bridge dividing delta sunspot of active region 12673. Res. Notes American Astron. Soc. 2018, vol. 2, iss. 1, article id. 8. DOI:https://doi.org/10.3847/2515-5172/aaa670.
43. Wheatland M.S., Sturrock P.A., Roumeliotis G. An optimization approach to reconstructing force-free fields. Astrophys. J. 2000, vol. 540, iss. 2, pp. 1150-1155. DOI:https://doi.org/10.1086/309355.
44. Yang Sh., Zhang J., Zhu X., Song Q. Block-induced complex structures building the flare-productive solar active region 12673. Astrophys. J. Lett. 2017, vol. 849, iss. 2, L21, 7 p. DOI:https://doi.org/10.3847/2041-8213/aa9476.
45. Yasnov L.V. On the nature of neutral-line-associated radio sources. Solar Phys. 2014, vol. 289, pp. 1215-1225. DOI:https://doi.org/10.1007/s11207-013-0396-3.
46. Zaitsev V.V. Gyrosynchrotron model of microwave sources associated with the magnetic field neutral line. Geomagnetism and Aeronomy. 2019, vol. 59, pp. 898-903. DOI:https://doi.org/10.1134/S0016793219070284.
47. URL: Zou P., Jiang Ch., Feng X., Zuo P., Wang Y. A two-step magnetic reconnection in a confined X-class flare in solar active region 12673. Astrophys. J. 2019, vol. 870, iss. 2, 97, 8 p. DOI:https://doi.org/10.3847/1538-4357/aaf3b7.
48. Zou P., Jiang Ch., Fengsi W., Feng X., Zuo P., Wang Y. Continuous null-point magnetic reconnection builds up a torus unstable magnetic flux rope triggering the X9.3 flare in solar AR 12673. Astrophys. J. 2020, vol. 890, iss. 1, 10, 8 p. DOI:https://doi.org/10.3847/1538-4357/ab6aa8.
49. URL: https://cdaw.gsfc.nasa.gov/CME_list (accessed September 25, 2020).
50. URL: ckp-rf.ru/usu/73606 (accessed September 25, 2020).
