Conveners
Poster Session 2.1
- Manolis Georgoulis (RCAAM of the Academy of Athens)
Measurements of the magnetic field’s twist play an important role in constraining dynamo theory, models of flux emergence and the prediction of flares. We aim to characterize methods of measuring twist directly from SDO/HMI vector magnetograms by generating Monte-Carlo synthetic data sets. By studying several example sunspots we found that the temporal fluctuations in the HMI vector...
We study the sunspot activity in relation to spotless days (SLDs) during the descending phase of solar cycle 11–24 to predict the amplitude of sunspot cycle 25. For this purpose, in addition to SLD, we also use the geomagnetic activity (aa index) during the descending phase of a given cycle. A very strong correlation of the SLD (R=0.68) and aa index(R=0.86) during the descending phase of a...
On a global scale chromospheric magnetic activity is represented by plages and enhanced chromospheric network. These phenomena significantly contribute to the variation of the solar UV radiation and the enhancement in chromospheric emission in the two strong resonance Ca II H & K lines. We present a set of excess brightness and area indices based on disk-resolved UV 1600Å images of the...
Far-side helioseismology is a technique used to detect activity signatures in the far hemisphere of the Sun, based on near-side wave field interpretation. We evaluated the performance of a new neural network approach, developed to improve the sensitivity of the seismic maps to the presence of far-side active regions, and thoroughly compared it with the standard method commonly applied to...
It is still an open question if the quiet Sun small-scale magnetic field mainly originates of a turbulent cascade acting on fields produced by a global-scale dynamo, or if it is mainly generated locally by a small-scale turbulent dynamo. Consequently, a number of numerical studies focusing on turbulent dynamos was carried out in the recent past. Despite of these works providing extremely...
This contribution describes the procedure by which we found relationship between the rotational velocity of the solar corona and the level of the solar activity (phase of the solar cycle) in the period of 2011 - 2020. The deviation of the speed from the mean value is ± 0.0239 °/day, which corresponds on the solar surface near the equator to ± 3.16 m/s, with a mean value of about 14.1 °/day...
Late-type stars often display multiple and variable levels of periodic magnetic activity. It is well established that our nearest stellar source, the Sun, manifests similar levels of magnetic activity, including the 11-year sunspot cycle discovered two centuries ago. This solar cycle dominates the properties of large-scale phenomena, such as flares and sunspots. However, little is known about...
