Pulsed nature of solar cycle 24
Solar cycle 24 is characterized by relatively weak sunspot activity and is developing according to the smallest cycle scenario (Svalgaard, Cliver, and Kamide, 2005). Using the Solar Dynamics Observatory (SDO) data for May 2010–September 2014, we present the results of a study of solar cycle 24 in the photosphere and corona during the ascending and maximum epochs. These data have been prepared in the form of synoptic maps (one map corresponds to one solar rotation) as functions of latitude and longitude for Carrington rotations CR2097–CR2154. To study the axisymmetric structure of the cycle, the maps have been averaged over longitude. Solar activity pulses, which are visible in an axisymmetric midlatitude magnetic flux, correspond to coronal brightening events in the extreme ultraviolet in the 193 Å band. Solar cycle 24 is characterized by weak magnetic polar activity, weakly pronounced high-latitude waves of coronal activity, and north–south asymmetry in the sign change of the polar solar magnetic field, which is directly connected with the asymmetry in an emerging magnetic flux in the region of sunspot activity and, hence, solar activity pulses. Thus, the north polar field became mainly positive in the latitude zone from 75.01° to 79.73° in 2013, while the south field started changing sign in September 2014.
KeywordsSolar Activity Magnetic Flux Solar Cycle Sunspot Number Carrington Rotation
Unable to display preview. Download preview PDF.
- Antalova, A. and Gnevyshev, M.N., Latitudinal distribution of sunspot areas during the period 1874–1976, Astron. Inst. Czech. Bul., 1985, vol. 36, p. 61.Google Scholar
- Benevolenskaya, E.E., A topological model of the solar magnetic field reversals, The Sun and Cool Stars, Tuominen, I., Moss, D., and Rudiger, G., Eds., Springer, 1991, vol. 380, pp. 234–236.Google Scholar
- Eigenson, M.S., Gnevyshev, M.N., Ol’, A.I., and Rubashev, B.M., Solnechnaya aktivnost' i ee zemnye proyavleniya (Solar Activity and its Manifestations at the Earth), Moscow: Izdatel’stvo Tekhniko-Teoreticheskoi Literatury, 1948.Google Scholar
- Makarov, V.I. and Fat’yanov, M.P., About dynamics of ripple belts, Solnechnye Dannye, 1980, no. 10, p. 96.Google Scholar
- Scherrer, P.H., Schou, J., Bush, R.I., Kosovichev, A.G., Bogard, R.S., Hoeksema, J.T., Liu, Y., Duvall, T.L., Jr., Zhao, J., Title, A.M., Schrijver, C.J., Tarbell, T.D., and Tomczyk, S., The helioseismic and magnetic imager (HMI) investigation for the solar dynamics observatory (SDO), Sol. Phys., 2012, vol. 275, pp. 207–227.CrossRefGoogle Scholar
- Svalgaard, L., Cliver, E.W., and Kamide, Y., Sunspot cycle 24: Smallest cycle in 100 years?, Astrophys. J. ASP Conf. Ser., 2005, vol. 346, pp. 401–408.Google Scholar