Skip to main content
SpringerLink
Log in

On Detecting the Fourth Gyrofrequency Harmonic in Microwave Emission Spectra above Sunspots

  • Published:
Cosmic Research Aims and scope Submit manuscript

Abstract

Spectral polarization observations of radio sources above sunspots are regularly carried out with the RATAN-600 radio telescope (RATAN is a Russian acronym for the Radio Astronomical Telescope of the Academy of Sciences). The in-depth studies of the spectra reveal new effects. In this paper, we analyze the manifestation of radio emission of the fourth gyrofrequency harmonic in microwave spectra obtained with 1-percent frequency resolution in a range of 3–18 GHz. Registration of the extraordinary mode in the short-wavelength range of the spectrum is compared to the model calculations of the second-to-fifth gyrofrequency harmonics against a background of the thermal bremsstrahlung emission of flocculi, surrounding the spot structure of an active region. The brightening of the extraordinary mode in the short-wavelength spectral range and the kinks in the intensity spectra of emission are analyzed. The interpretation of the RATAN-600 observational data with probable diagnostics of the emission of the fourth gyrofrequency harmonic is considered as examples.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Fig. 7.
Fig. 8.

Similar content being viewed by others

REFERENCES

  1. Lin, H., Kuhn, J.R., and Coulter, R., Coronal magnetic field measurements, Astrophys. J. Lett., 2004, vol. 613, no. 2, pp. L177–L180.

    Article  ADS  Google Scholar 

  2. Tomczyk, S., Zhang, J., Bastian, T., and Leibacher, J.W., Preface, Sol. Phys., 2013, vol. 288, no. 2, pp. 463–465.

    Article  ADS  Google Scholar 

  3. Aschwanden, M.J., Outstanding problems in solar physics, J. Astrophys. Astron., 2008, vol. 29, nos. 1–2, pp. 3–16.

    Article  ADS  Google Scholar 

  4. Bogod, V. and Gelfreikh, G., Measurements of the magnetic field and the gradient of temperature in the solar atmosphere above a flocculus using radio observations, Sol. Phys., 1980, vol. 67, pp. 29–46.

    Article  ADS  Google Scholar 

  5. Akhmedov, S.B., Gelfreikh, G.B., Bogod, V.M., and Korzhavin, A.N., The measurement of magnetic fields in the solar atmosphere above sunspots using gyroresonance emission, Sol. Phys., 1982, vol. 79, no. 1, pp. 41–58.

    Article  ADS  Google Scholar 

  6. Alissandrakis, C.E. and Kundu, M.R., Center-to-limb variation of a sunspot-associated microwave source, Astron. Astrophys., 1984, vol. 139, no. 2, pp. 271–284.

    ADS  Google Scholar 

  7. Gelfreikh, G.B., Pilyeva, N.A., and Ryabov, B.I., On the gradient of coronal magnetic fields from radio observations, Sol. Phys., 1997, vol. 170, no. 2, pp. 253–264.

    Article  ADS  Google Scholar 

  8. Grebinskij, A., Bogod, V., Gelfreikh, G., Urpo, S., Pohjolainen, S., and Shibasaki, K., Microwave tomography of solar magnetic fields, Astron. Astrophys. Suppl. Ser., 2000, vol. 144, no. 1, pp. 169–180.

    Article  ADS  Google Scholar 

  9. White, S.M., Radio measurements of coronal magnetic fields, in Proceedings of the International Scientific Conference on Chromospheric and Coronal Magnetic Fields (ESA SP-596), Innes, D.E., Lagg, A., and Solanki, S.K., Eds., 2005, CD-ROM, id 10.1.

  10. Kakinuma, T. and Swarup, G., Model for the sources of the slowly varying component of microwave solar radiation, Astrophys. J., 1962, vol. 136, pp. 975–994.

    Article  ADS  Google Scholar 

  11. Zheleznyakov, V.V., Radio Emission of the Sun and Planets, Oxford: Pergamon, 1970.

    Google Scholar 

  12. Gelfreikh, G.B., Microwave diagnostics of solar magnetic fields, in The Dynamics of Current Sheets and the Physics of Solar Activity, Riga: Zinante, 1982, pp. 116–124.

    Google Scholar 

  13. Alissandrakis, C. E., Kundu, M. R., and Lantos, P., A model for sunspot associated emission at 6 CM wavelength, Astron. Astrophys., 1980, vol. 82, nos. 1–2, pp. 30–40.

    ADS  Google Scholar 

  14. Hurford, G.J., Gary, D.E, Bastian, T.S., and White, S.M., FASR—A frequency-agile solar radiotelescope, in The 194th American Astronomical Society Meeting, Bull. Am. Astron. Soc., 1995, vol. 31, p. 956.

    ADS  Google Scholar 

  15. Bastian, T.S., Gary, D.E., White, S., et al., Radio coronal magnetography of a large active region, in Joint American Astronomical Society/American Geophysical Union Triennial Earth–Sun Summit Meeting no. 1, AMS, 2015, id 113.01.

  16. Alissandrakis, C.E., Gelfreikh, G.B., Borovik, V.N., Korzhavin, A.N., Bogod, V.M., Nindos, A., and Kundu, M.R., Spectral observations of active region sources with RATAN-600 and WSRT, Astron. Astrophys., 1993, vol. 270, nos. 1–2, pp. 509–515.

    ADS  Google Scholar 

  17. Alissandrakis, C.E., Borgioli, F., Chiuderi, D.F., et al., Coronal magnetic fields from microwave polarization observations, Sol. Phys., 1996, vol. 167, nos. 1–2, pp. 167–179.

    Article  ADS  Google Scholar 

  18. Casini, R., White, S.M., and Judge, P.G., Magnetic diagnostics of the solar corona: Synthesizing optical and radio techniques, Space Sci. Rev., 2017, vol. 210, nos. 1–4, pp. 145–181.

    Article  ADS  Google Scholar 

  19. Bogod, V.M., RATAN-600 radio telescope in the 24th solar-activity cycle. I. New opportunities and tasks, Astrophys. Bull., 2011, vol. 66, no. 2, pp. 190–204.

    Article  ADS  Google Scholar 

  20. Tokhchukova, S.Kh., Korzhavin, A.N., Bogod, V.M., et al., Computation of the horizontal size of the RATAN-600 beam pattern for the “Southern Sector with a Flat Reflector” mode with allowance for the parameters of primary feeds, Astrophys. Bull., 2014, vol. 69, no. 3, pp. 356–367.

    Article  ADS  Google Scholar 

  21. Bogod, V.M., Stupishin, A.G., and Yasnov, L.V., On magnetic fields of active regions at coronal heights, Sol. Phys., 2012, vol. 276, nos. 1–2, pp. 61–73.

    Article  ADS  Google Scholar 

  22. Bogod, V.M. and Yasnov, L.V., On the comparison of radio-astronomical measurements of the height structure of magnetic field with results of model approximations, Astrophys. Bull., 2009, vol. 64, no. 4, pp. 372–384.

    Article  ADS  Google Scholar 

  23. Bogod, V.M. and Yasnov, L.V., Determination of the structure of the coronal magnetic field using microwave polarization measurements, Sol. Phys., 2016, vol. 291, no. 11, pp. 3317–3328.

    Article  ADS  Google Scholar 

  24. Kaltman, T.I., Bogod, V.M., Stupishin, A.G., and Yasnov, L.V., The altitude structure of the coronal magnetic field of AR 10933, Astron. Rep., 2012, no. 10, pp. 790–799.

  25. Nita, G.M., Fleishman, G.D., Jing, J., et al., Three-dimensional structure of microwave source from solar rotation stereoscopy versus magnetic extrapolations, Astrophys. J., 2011, vol. 737, no. 2, id 82.

  26. Bogod, V.M., Alesin, A.M., and Pervakov, A.A., RATAN-600 radio telescope in the 24th solar-activity cycle. II. Multi-octave spectral and polarization high-resolution solar research system, Astrophys. Bull., 2011, vol. 66, no. 2, id 205.

  27. Peterova, N.G., Opeikina, L.V., and Topchilo, N.A., “Halo” type sources from microwave observations with high angular resolution, Geomagn. Aeron. (Engl. Transl.), 2014, vol. 54, no. 8, pp. 1053–1057.

  28. Selhorst, C.L., Silva-Válio, A., and Costa, J.E.R., Solar atmospheric model over a highly polarized 17 GHz active region, Astron. Astrophys., 2008, vol. 488, no. 3, pp. 1079–1084.

    Article  ADS  Google Scholar 

  29. Stupishin, A.G., Kaltman, T.I., Bogod, V.M., and Yasnov, L.V., Modeling of solar atmosphere parameters above sunspots using RATAN-600 microwave observations, Sol. Phys., 2018, vol. 293, no. 1, id 13.

Download references

ACKNOWLEDGMENTS

The study was performed according to the Government Contract no. АААА-А17-117011810013-4 and supported in part by the Russian Foundation for Basic Research (project no. 18-02-00045) and Program 28 of the Presidium of the Russian Academy of Sciences (Cosmos: Studies of Fundamental Processes and Their Interrelations, project 1D).

Author information

Authors and Affiliations

  1. Special Astrophysical Observatory, St. Petersburg Branch, Russian Academy of Sciences, 196140, St. Petersburg, Russia

    T. I. Kaltman & V. M. Bogod

  2. ITMO University, 197101, St. Petersburg, Russia

    V. M. Bogod

Authors
  1. T. I. Kaltman
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. V. M. Bogod
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to T. I. Kaltman.

Additional information

Translated by E. Petrova

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Kaltman, T.I., Bogod, V.M. On Detecting the Fourth Gyrofrequency Harmonic in Microwave Emission Spectra above Sunspots. Cosmic Res 57, 1–9 (2019). https://doi.org/10.1134/S0010952519010040

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1134/S0010952519010040

Search

Navigation