Faculty of Physics
M.V.Lomonosov Moscow State University
Menu
Regular Article

The cyclic activity of the sun from observations of the activity indices at different time scales

E.A. Druevich, G.V. Yakunina

Moscow University Physics Bulletin 2015. 70. N 4. P. 282

  • Article
Annotation

With the time–frequency analysis of the series of observations of one of the global indices of solar activity, viz., the radio flux F$_{10.7}$ at a wavelength of 10.7 cm (2.8 GHz), the most probable value of the main cycle period has been determined. This value is 10.2 yr, which is consistent with the generally accepted estimates. Simultaneously with the main cycle of activity, several lowamplitude cycles with cyclicity periods from 1.3 to 100 yr were identified. With the method of continuous wavelet transform with Morlet mother wavelets, we analyzed the other solar indices that are associated with the radiation at different heights in the solar atmosphere: the relative number of sunspots, SSN, the chromospheric index, $\textit{Mg II}$, at 280 nm, the fluxes in the coronal line at 530.3 nm, F$_{530}$, the $\textit{Flare Index}$, and the index of a total number of flares, $\textit{Counts of flares}$. The obtained time–frequency characteristics turned out to be generally similar. Differences in the results for the solar indices occur during the strengthening of stochastic processes in the maxima and minima of the main cycle.

Received: 2015 April 3
Approved: 2015 August 28
PACS:
90.00.00 GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS
96.00.00 Solar system; planetology
96.60.-j Solar physics
96.60.Q- Solar activity
Authors
E.A. Druevich, G.V. Yakunina
Sternberg Astronomical Institute, Moscow State University, Universitetskii pr. 13, Moscow, 119991 Russia
Issue 4, 2015

Moscow University Physics Bulletin

Science News of the Faculty of Physics, Lomonosov Moscow State University

This new information publication, which is intended to convey to the staff, students and graduate students, faculty colleagues and partners of the main achievements of scientists and scientific information on the events in the life of university physicists.