Title: Understanding the Internal Structure of the Sun
Author: Sabatino Sofia
Affil: Yale University
Email: sofia@astro.yale.edu
Authors: Linghuai Li
Abstract: To understand solar variability beyond that produced by active regions and network, it is necessary to understand the nature (and the variability) of the solar interior on the relevant timescales. For variations important to climate change (decades to centuries) the only process that affects the solar interior is the increase of the internal magnetic fields as a consequence of the solar dynamo, and its decrease when the fields float to the surface and appear as magnetic activity.
We have developed a structure and evolution numerical code that includes the magnetic fields (and turbulence) as components of pressure and internal energy, and as modifiers of energy transport. We can compute the behavior of all the global solar parameters throughout the activity cycle, and the oscillation variations resulting from the structural changes. We will describe the most current results, and their comparison with existing observations.
Title: Mechanisms for Solar Irradiance Variability
Author: J. R. Kuhn
Affil: IfA/UH
Email: Kuhn@ifa.hawaiii.edu
Authors: J. D. Armstrong
Abstract: Statistical accounts of the solar irradiance changes seem to suggest that sunspots and faculae can account for most of the apparent variability. This talk will show how these models fall short of a more detailed description of the solar irradiance variability, particularly on long timescales, and when a physical description of the solar convection zone is included in the model effort. We explore high precision solar photometry, numerical convection experiments, and helioseismology implications to derive physical constraints on the solar variability mechanisms. We find that faculae and sunspots do not account for the sun's variability.
Title: Effect of solar surface magnetic activity on irradiance changes
Author: Werner Schmutz
Affil: PMOD/WRC Davos
Authors: Sami Solanki
Affils: MPA Lindau
Abstract: We review work that aims at explaining the solar irradiance variability being due to changes in the magnetic field at the solar surface. We concentrate mainly on results produced by the Lindau/Zurich group, assuming that the results of others are presented in separate talks. Early work used proxies of the surface magnetic field to reconstruct the irradiance. More recently, detailed reconstructions using magnetograms have been carried out. These turn out to be successful in reproducing the variations of the total and spectral irradiance on times scales up to a solar cycle. For longer time scales methods for reconstructing of the Sun's magnetic field are currently being developed. We present the basis for a relationship between solar cycle length and the sun's open magnetic flux at activity minimum. This may indicate a relationship between cycle length and irradiance.