Abstract
A gradual microwave darkening during several days of the preflare phase in the active region (AR) NOAA 9077, before the powerful proton event on 14 July 2000 was detected. The associated change of the circular polarization structure in the form of narrow-band double inversion of the sign was marked. The effects were revealed in a wide range of radio observations at the RATAN-600 radiotelescope and were confirmed by data from the Nobeyama Radio Heliograph (NRH) at 17 GHz and the Siberian Solar Radio Telescope (SSRT, Irkutsk) at 5.8 GHz. We propose an interpretation of the observed effects as an indication of gradual formation of a filament in the vertical structure of the AR. Destabilization of this filament apparently caused the major flare with a coronal mass ejection (CME).
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Akhmedov, Sh. B., Borovik, V. N., Gelfreikh, G. B., Bogod, V. M., Korzhavin, A. N., Petrov, Z. E., Dikij, V. N., Lang, K. R., and Willson, R. F.: 1986, Astrophys. J. 301, 460.
Bogod, V. M., Garaimov, V. I., Komar, N. P., and Korzhavin, A. N.: 1999a, in Magnetic Fields and Solar Processes, ESA SP-448, p. 1253.
Bogod, V., Grebinskij, A., Garaimov, V., Urpo, S., Fu, Q. J., and Zhang, H.: 1999b, Bull. Spec. Astrophys. Obs. 48, 17.
Chiuderi-Drago, F., Alissandrakis, C. E., Bastian, T., Bocchialini, K., and Harrison, R. A.: 2001, Solar Phys. 199, 115.
Covington, A. E.: 1973, Solar Phys. 33, 439.
Gelfreikh, G. B.: 1998, ASP Series 155, 110.
Gelfreikh, G. B., Bogod, V. M., Abramov-Maximov, V. E., and Tsvetkov, S. V.: 1993, ASP Conf. Ser. 46, 271.
Gopalswamy, N., Yashiro, S., Kaiser, M. L., Thompson, B. J., and Plunkett, S.: 1999, in T. S. Bastian, N. Gopalswamy, and K. Shibasaki (eds), Solar Physics with Radio Observations. Proceedings of the Nobeyama Symposium, NRO Report 479, 207.
Fujiki, K. and Nakajima, H: 2000, Adv. Space Res. 26, 477.
Hanaoka Y.: 1997, Solar Phys. 173, 319.
Heinzel, P., Schmieder, B., and Tziotziou, K.: 2001, Astrophys. J. 561, 223.
Heyvaerts, J., Priest, E. R., and Rust, D. M.: 1977, Astrophys. J. 216, 123.
Hudson, H.: 1999, Solar Phys. 190, 91.
Korol'kov, D. V. and Parijskij, Yu. N.: 1979, Sky Telesc. 57, 329.
Kundu, M., Melozzi, M., and Shevgaonkar, R.: 1986, Astrophys. J. 167, 166.
Lang, K. R., Willson, R. F., Kile, J. N., Jemen, J., Strong, K. T., Bogod, V. M., Gelfreikh, G. B., Ryabov, B. I., Hafizov, S. R., Abramov, V. E., and Svetkov, S. V.: 1993, Astrophys. J. 419, 398.
Liu, Y. and Zhang, H.: 2001, Astron. Astrophys. 372, 1019.
Schmahl, E. J., Bobrowsky, M., and Kundu, M. R.: 1981, Solar Phys. 71, 311.
Shibata, K.: 1999, in T. S. Bastian, N. Gopalswamy, and K. Shibasaki (eds.), Solar Physics with Radio Observations. Proceedings of the Nobeyama Symposium, NRO Report 479, 381.
Tanaka, H. and Énomé, S.: 1975, Solar Phys. 40, 123.
White, S. M., Kundu, M. R., and Gopalswamy, N.: 1992, Astrophys. J. Suppl. Ser. 78, 599.
Yan, Y., Deng, Y., Karlický, M., Fu, Q., Wang, S., and Liu, Y.: 2001, Astrophys. J. 551, 115.
Zheleznyakov, V. V.: 1970, Radio Emission of the Sun and the Planets, Pergamon Press Ltd., Oxford.
Zlotnik, E. Ya.: 2001, Radiophys. Quant. Electronics 44, 53.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Tokhchukova, S., Bogod, V. Detection of the Long-Term Microwave `Darkening' Before the 14 July 2000 Flare. Sol Phys 212, 99–109 (2003). https://doi.org/10.1023/A:1022967619993
Issue Date:
DOI: https://doi.org/10.1023/A:1022967619993