The solar polar magnetic field has attracted the attention of researchers since the polar magnetic field reversal was revealed in the middle of the last century (Babcock and Livingston, 1958). The polar magnetic field has regularly reversed because the magnetic flux is transported from the sunspot formation zone owing to differential rotation, meridional circulation, and turbulent diffusion. However, modeling of these processes leads to ambiguous conclusions, as a result of which it is sometimes unclear whether a transport model is actual. Thus, according to the last Hinode data, the problem of a standard transport model (Shiota et al., 2012) consists in that a decrease in the polar magnetic flux in the Southern Hemisphere lags behind such a decrease in the flux in the Northern Hemisphere (from 2008 to June 2012). On the other hand, Svalgaard and Kamide (2012) consider that the asymmetry in the sign reversal simply results from the asymmetry in the emerging flux in the sunspot formation region. A detailed study of the polar magnetic flux evolution according to the Solar Dynamics Observatory (SDO) data for May 2010–December 2012 is illustrated in the present work. Helioseismic & Magnetic Imager (HMI) magnetic data in the form of a magnetic field component along the line of sight (the time resolution is 720 s) are used here. The magnetic fluxes in sunspot formation regions and at high latitudes have been compared.
KeywordsMagnetic Flux Solar Cycle Solar Magnetic Field Carrington Rotation Solar Dynamics Observatory
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- Jiang, J., Cameron, R.H., Schmitt, D., and Schüssler, M., Can surface flux transport account for the weak polar field in cycle 23?, Space Sci. Rev., 2011.Google Scholar
- Pucci, S., Poletto, G., Sterling, A.C., and Romoli, M., Solar polar X-ray jets and multiple bright points: Evidence for sympathetic activity, Astrophys. J. Lett., vol. 745, no. 2, p. L31.Google Scholar
- Savcheva, A. and Cirtain, J.E., Deluca, E.E., Lundquis, L.L., Golub, L., Weber, M., Shimojo, M. Shibasaki, K., Sakao, T., and Narukage, N., Study of polar jet parameters based on Hinode XRT observations, Obs. Publ. Astron. Soc. Japan, 2007, vol. 59, pp. S771–S778.Google Scholar
- Scherrer, P.H., Schou, J., Bush, R.I., Kosovichev, A.G., Bogard, R.S., Hoeksema, J.T., Liu, Y., Duvall, Jr.T.L., Zhao, J., Title, A.M., Schrijver, C.J., Tarbell, T.D., and Tomczyk, S., The Helioseismic and 7 Magnetic Imager (HMI) Investigation for the Solar Dynamics Observatory (SDO) Sol. Phys., 2012, vol. 275, pp. 207–227.CrossRefGoogle Scholar
- Severnyi, A.B., The nature of solar magnetic fields (The fine structure of the field), Sov. Astron. Lett., 1965, no. 9, pp. 171–182.Google Scholar
- Svalgaard, L. Cliver, E.W., and Kamide, Y., Sunspot cycle 24: Smallest cycle in 100 years? ASP Conf. Ser., 2005, vol. 346, p. 401.Google Scholar
- Svalgaard, L. and Kamide, Y., Asymmetric solar polar field reversals, Astrophys. J. Lett., 2012, vol. 763, p. 6.Google Scholar