Related papers: Multicomponent Activity Cycles using Hilbert-Huang…
The application of the Wavelet analysis and Fourier analysis to the dataset of variations of radiation fluxes of solar-like stars and the Sun is examined. In case of the Sun the wavelet-analysis helped us to see a set of values of periods…
We analyse the relation between the activity cycle length and the Rossby number and collected a sample of 44 main sequence stars with well-known activity cycle periods and rotation periods. We find a linear behaviour in the…
Studies on the periodic variation and the phase relationship between different solar activity indicators are useful for understanding the long-term evolution of solar activity cycle. Here we report the statistical analysis of grouped solar…
Relative variations in the number of sunspots and sunspot groups in activity cycles have been analyzed based on data from the Kislovodsk Mountain Astronomical Station and international indices. The following regularities have been…
The 11-year cycle of solar activity follows Hale's law by reversing the magnetic polarity of leading and following sunspots in bipolar regions during the minima of activity. In the 1996-97 solar minimum, most solar activity emerged in…
Context. The variations of solar activity over long time intervals using a solar activity reconstruction based on the cosmogenic radionuclide 10Be measured in polar ice cores are studied. Methods. By applying methods of nonlinear dynamics,…
Quasi-biennial oscillations (QBOs) are considered as a fundamental mode of solar magnetic activity at low latitudes ($\leq50^\circ$). However, the evolutionary aspect and the hemispheric distribution of solar QBOs at high latitudes…
The extension of the sunspot number series backward in time is of considerable interest for dynamo theory, solar, stellar, and climate research. We have used records of the Be-10 concentration in polar ice to reconstruct the average sunspot…
We studied new simultaneous observations of the flux variations of the photospheric and chromospheric emissions of 33 solar-type stars and Sun during the HK-project that were conducted over the past 20 years. In addition to the known cyclic…
By combining ground-based spectrographic observations of variability in the chromospheric emission from Sun-like stars with the variability seen in their eigenmode frequencies, it is possible to relate the changes observed at the surfaces…
We study a sample of 21 young and active solar-type stars with spectral types ranging from late F to mid K and characterize the behaviour of their activity. We apply the continuous period search (CPS) time series analysis method on 16 to 27…
Long-running measurements of the solar radio flux density at 810 MHz were processed. Based on the least-squares method and using modified periodograms and an iterative technique of fitting and subtracting sinusoids in the time domain,…
We use archival daily spot coverage measurements from Howard et al. (1984) to study the rotational modulation of the Sun as though it were a distant star. A quasi-periodic Gaussian process measures the solar rotation period $P_\mathrm{rot}…
The level of solar magnetic activity, as exemplified by the number of sunspots and by energetic events in the corona, varies on a wide range of time scales. Most prominent is the 11-year solar cycle, which is significantly modulated on…
Solar activity affects the whole heliosphere and near-Earth space environment. It has been reported in the literature that the mechanism responsible for the solar activity modulation behaves like a low-dimensional chaotic system. Studying…
The success of helioseismology is due to its capability to accurately measure the p-mode parameters of the solar eigenmode spectrum, which allow us to infer unique information about the internal structure and dynamics of the Sun. It also…
One obvious feature of the solar cycle is its variation from one cycle to another. In this article, we review the dynamo models for the long-term variations of the solar cycle. By long-term variations, we mean the cycle modulations beyond…
Solar cycle is modeled as a forced and damped harmonic oscillator and the amplitudes, frequencies, phases and decay factors of such a harmonic oscillator are estimated by non-linear fitting the equation of sinusoidal and transient parts to…
The evolution of the solar activity comprises, apart from the well-known 11-year cycle, various temporal scales ranging from months up to the secondary cycles known as mid-term oscillations. Its nature deserves a physical explanation. In…
A phenomenological model is presented for the quantitative description of individual solar cycles' features, such as onset, intensity, evolution, in terms of the number of M and X-class solar flares. The main elements of the model are the…