Anticorrelation of Variations of the Magnetic Field of a Sunspot and the Brightness of Its Umbra in Long-Period Sunspot Oscillations

Abstract

Changes in the umbra brightness and in the magnetic field over time should occur on long-period sunspot oscillations in accordance with Birman’s idea of inhibition of circulation (overturning) convection by a strong vertical magnetic field in antiphase mode.When the sunspot as a whole shifts upward, its power flux tube expands with a fixed magnetic flux, the magnetic field decreases, and the umbra brightness should increase. Vice versa, when the magnetic flux tube of the sunspot is lowered, it is compressed, the field grows, and the umbra brightness should decrease. Until now, this oscillatory process, which is described by the theoretical model of a shallow sunspot, has remained unexplored. This paper attempts to prove the Birman effect (Biermann, 1941) on the example of long-period oscillations of the sunspot 2010/12/07-13 (NOAA 11 133), for which there are available data from both the Solar and Heliospheric Observatory (SOHO) and Solar Dynamics Observatory (SDO).

This is a preview of subscription content, access via your institution.

Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.

REFERENCES

  1. 1

    Biermann, L.V., Der gegenwärtige Stand der Theorie konvektiver Sonnenmodelle, Viertel jahresschr. Astron. Ges., 1941, vol. 76, pp. 194–200.

    Google Scholar 

  2. 2

    Bray, R.J. and Loughead, R.E., Sunspots, London: Chapman and Hall,1964.

    Google Scholar 

  3. 3

    Efremov, V.I., Parfinenko, L.D., and Solov’ev, A.A., Investigation of long-period oscillations of sunspots with ground-based (Pulkovo) and SOHO/MDI data, Sol. Phys., 2010, vol. 267, pp. 279–293.

    Article  Google Scholar 

  4. 4

    Efremov, V.I., Parfinenko, L.D., and Solov’ev, A.A., Sunspot oscillations as derived from the SOHO/MDI magnetograms, Cosmic Res., 2012, vol. 50, no. 1, pp. 44–55. https://doi.org/10.1134/S0010952511060025

    Article  Google Scholar 

  5. 5

    Efremov, V.I., Parfinenko, L.D., Solov’ev, A.A., and Kirichek, E., long-period oscillations of sunspots observed by SOHO/MDI, Sol. Phys., 2014, vol. 289, pp. 1983–1998. https://doi.org/10.1007/s11207-013-0451-0

    Article  Google Scholar 

  6. 6

    Efremov, V.I., Parfinenko, L.D., Solov’ev, A.A., and Riehokainen, A., Long-term oscillations of sunspot magnetic field by simultaneous observations of GONG and MDI/SOHO, Geomagn. Aeron. (Engl. Transl.), 2016, vol. 56, no. 7, pp. 897–902. https://doi.org/10.1134/S0016793216070057

  7. 7

    Efremov, V.I., Parfinenko, L.D., and Solov’ev, A.A., Analysis of 12-hour orbital artifact in the SDO/HMI data and Low-frequency oscillations of sunspots magnetic field, Geomagn. Aeron. (Engl. Transl.), 2017, vol. 57, no. 8, pp. 1045–1055. https://doi.org/10.1134/S0016793217080072

  8. 8

    Efremov, V.I., Solov’ev, A.A., Parfinenko, L.D., et al., Long-term oscillations of sunspot magnetic field and a special class of artifacts in SOHO/MDI and SDO/HMI data, Astrophys. Space Sci., 2018, vol. 363, no. 3, pp. 1–14. https://doi.org/10.1007/s10509-018-3284-3

    Article  Google Scholar 

  9. 9

    Golyandina, N., Nekrutkin, V., and Zhigljavsky, A., Analysis of Time Series Structure: SSA and Related Techniques, London: Chapman and Hall/CRC, 2001.

    Book  Google Scholar 

  10. 10

    Gurman, J.B. and House, L.L., Vector magnetic fields in sunspots. Part 1. Weak-line observations, Sol. Phys., 1981, vol. 71, no. 1, pp. 5–20.

    Article  Google Scholar 

  11. 11

    Korolkova, O.A. and Efremov, V.I., Y-P2P effect according to SDO data and anti-correlation of oscillations of sunspots magnetic field and umbra area, Geomagn. Aeron. (Engl. Transl.), 2019, vol. 59, no. 7, pp. 827–831.https://doi.org/10.1134/S0016793219070181

  12. 12

    Makarov, V.I., The size and form of sunspots in some segments of the continuous spectrum, Izv. Gl. Astron. Obs. Pulkove, 1968, no. 184, pp. 58–65.

  13. 13

    Sitnik, G.F., On the problem of the nature of sunspots, Publ. Gos. Astron. Inst. im. Shternberga, 1939, vol. 11, pp. 5–41.

    Google Scholar 

  14. 14

    Rempel, M., Numerical sunspot models: Robustness of photospheric velocity and magnetic field structure, Astrophys. J., 2012, vol. 750, no. 1, id. 62. https://doi.org/10.1088/0004-637X/750/1/62

  15. 15

    Solov’ev, A.A. and Kirichek, E.A., Basic properties of sunspots: equilibrium, stability and eigen oscillations, Astrophys. Space Sci., 2014, vol. 352, no. 1, pp. 23–42. https://doi.org/10.1007/s10509-014-1881-3

    Article  Google Scholar 

  16. 16

    Solov’ev, A.A. and Kirichek, E.A., Analytical model of an asymmetric sunspot with a steady plasma flow in its penumbra, Sol. Phys., 2016, vol. 291, no. 6, pp. 1647–1663. https://doi.org/10.1007/s11207-016-0922-1

    Article  Google Scholar 

  17. 17

    Solov’ev, A.A., Parfinenko, L.D., Efremov, V.I., et al., Structure of photosphere under high resolution: Granules, faculae, micropores, intergranular lanes, Astrophys. Space Sci., 2019, vol. 364, no. 12, pp. 222–234. https://doi.org/10.1007/s10509-019-3710-1

    Article  Google Scholar 

  18. 18

    Zwaan, C., Sunspot models: A study of sunspot spectra, Rech. Astron. Obs. Utrecht, 1965, vol. 17, no. 4.

Download references

ACKNOWLEDGMENTS

The authors are grateful to the SOHO and SDO teams for the opportunity to use the observational data.

Funding

This work was supported by the Russian Foundation for Basic Research (project no. 18-02-00168).

Author information

Affiliations

Authors

Corresponding author

Correspondence to A. A. Solov’ev.

Ethics declarations

The authors declare that they have no conflict of interest.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Efremov, V.I., Solov’ev, A.A., Parfinenko, L.D. et al. Anticorrelation of Variations of the Magnetic Field of a Sunspot and the Brightness of Its Umbra in Long-Period Sunspot Oscillations. Geomagn. Aeron. 60, 1023–1027 (2020). https://doi.org/10.1134/S0016793220080071

Download citation