The Quiet Sun Dynamo: Shallow versus Deep

Michigan State University, East Lansing MI

Investigators

Abstract

The Principal Investigator (PI) will investigate the magnetodynamics of the solar surface and upper convection zone in both quiet and active regions of the Sun, in order to determine the origin of the 'quiet Sun' magnetic field. He will evaluate the relative contributions of shallow surface dynamo action and deep convection zone dynamo action, as well as establish the rate of magnetic flux emerging from these two processes, by comparing observations with calculations from dynamo and magnetoconvection simulations within a supergranule-scale portion of the solar surface. His simulations will include the distribution of vertical and horizontal magnetic field strengths, the spectrum of vertical and horizontal magnetic fields, and the variation of supergranule sizes with the solar cycle. The PI's simulations solve the non-linear, compressible, three-dimensional equations for conservation of mass, momentum, and internal energy, as well as the induction equation for the magnetic field. The PI's model uses a tabular equation-of-state to determine the Local Thermodynamic Equilibrium pressure, temperature, opacities, and source functions, as a function of log density and internal energy. The PI is motivated by the fact that the behavior of magnetic fields near the solar surface is the ultimate driver of Earth's space weather. The simulation results will be posted on multiple web sites where they will be widely available to the solar scientific community and to the general public. The PI will mentor a female collaborator at Michigan State University in the use and analysis of his simulations and observations. The simulation results from this effort will also be used to enhance a museum exhibit demonstrating how scientists use sophisticated models, now being constructed at the Lansing, Michigan "Impression 5 Science Center," which hosts over 100,000 people annually, both individually and in school groups.