The Latest Developments in Solar Dynamo: a key to solar/stellar magnetic activity and variability

Author: Rosaria Simoniello

Affiliation: Geneva University, Chemin des Maillettes 51, 1290 Sauverny, Switzerland

The multitude of activity phenomena on the solar surface are related to magnetic fields
believed to be driven by a dynamo mechanism acting in the tachocline. This global
dynamo involves the generation and evolution of the largest features of the sun, such as
sunspots, the overall magnetic polarity of the sun, and the short and long-term amplitude
variations in solar activity cycles.
Recent findings from helioseismic and surface magnetic field observations have rapidly
changed our picture of the principles driving solar dynamo while, the analysis of 10 000
year reconstructed past solar activity from 10Be ice cores and 14C in tree rings data, has
shed light on the origin of the observed amplitude fluctuations in solar cycle.
Stellar data have achieved a richness comparable to that of solar data thanks to a wealth
of new spectro-polarimetric information at increasing temporal and spatial resolution
and the new era of statistical studies of unprecedentedly huge samples of stars observed
by space-borne telescopes like KEPLER and COROT. These data are essential for the
understanding of the effect of stellar mass on the resulting magnetic activity through a
dynamo mechanism. How dynamo efficiency goes with stellar evolution, is the key for
understanding the influences of solar/stellar magnetic activity in favoring life on Earth
and planets.
In this talk, therefore, I will review the latest developments in solar dynamo bringing
together the results coming from the solar and stellar community. With the discovery of
literally thousands of planets beyond our solar system, the Sun-Earth and Star-Planet
Connection is quickly emerging as a new area of investigation of the impacts of magnetic
activity on planets.