Related papers: Transitional dynamics of the solar convection zone
Context. The relation between solar surface rotation and sunspot activity still remains open. Sunspot activity has dramatically reduced in solar cycle 24 and several solar activity indices and flux measurements experienced unprecedentedly…
We examine the evolution of the zonal flow pattern in the upper solar convection zone during the current extended solar minimum, and compare it with that during the previous minimum. The results suggest that a configuration matching that at…
Differences between observed and theoretical eigenfrequencies of the Sun have characteristics which identify them as arising predominantly from properties of the oscillations in the vicinity of the solar surface: in the super-adiabatic,…
The solar cycle is a complex phenomenon. To comprehensively understand it, we have to study various tracers. The most important component of this complex is the solar dynamo, which is understood as self-excitation of the solar magnetic…
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…
We analyze spectral properties of solar convection in the range of depths from 0 to 19~Mm using subsurface flow maps obtained by the time-distance heiioseismology analysis of solar-oscillation data from the Helioseismic and Magnetic Imager…
Understanding solar turbulent convection and its influence on differential rotation has been a challenge over the past two decades. Current models often overestimate giant convection cells amplitude, leading to an effective Rossby number…
The sunspot activity is the end result of the cyclic destruction and regeneration of magnetic fields by the dynamo action. We propose a new method to analyze the daily sunspot areas data recorded since 1874. By computing the power spectral…
The temporal variations of the rotation rate in the solar interior are studied using frequency splittings from Global Oscillations Network Group (GONG) data obtained during the period 1995-99. We find alternating latitudinal bands of faster…
The connection between nuclear fusion in the Sun's core and solar irradiance is obscured among other things by uncertainty over the mechanism of coronal heating. Data for solar wind density and velocity, sunspot number, and EUV flux suggest…
The dynamic activity of stars such as the Sun influences (exo)planetary space environments through modulation of stellar radiation, plasma wind, particle and magnetic fluxes. Energetic stellar phenomena such as flares and coronal mass…
The Sun is the main energy source to Earth, and understanding its variability is of direct relevance to climate studies. Measurements of total solar irradiance exist since 1978, but this is too short compared to climate-relevant time…
The sunspot position from Greenwich Photoheliographic Results (GPR), US Air Force Solar Optical Observing Network and National Oceanic and Atmospheric Administration (USAF/NOAA), and Debrecen Photoheliographic Data (DPD) data bases in the…
The use of the spotless days to predict the future solar activity is here revised based on the new version of the sunspot number index with a 24-month filter. Data from Solar Cycle (SC) 10 are considered because from this solar cycle the…
Our knowledge of the long-term evolution of solar activity and of its primary modulation, the 11-year cycle, largely depends on a single direct observational record: the visual sunspot counts that retrace the last 4 centuries, since the…
The heliophysics catalogues published by the Ebro Observatory during 1910--1937 have been converted into a digital format in order to provide the data for computational processing. This has allowed us to study in detail the North-South…
We have measured the meridional motions of the magnetic elements in the Sun's surface layers since 1996 and find systematic and substantial variations. In general the meridional flow speed is fast at cycle minima and slow at cycle maxima.…
We use subsurface-flow velocity maps inferred by time--distance helioseismology from Doppler measurements with the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO) to investigate variations of large-scale…
In solar-like oscillators, acoustic waves are excited by turbulent motion in the convective envelope and propagate inward, generating a variety of standing pressure modes. When combining together the power of several solar acoustic modes,…
Duration of the extended solar cycles is taken into the consideration. The beginning of cycles is counted from the moment of polarity reversal of large-scale magnetic field in high latitudes, occurring in the sunspot cycle n till the…