Solar Field Mapping and Dynamo Behavior

Kenneth H Schatten

doi:10.1155/2012/923578

Abstract

We discuss the importance of the Sun’s large-scale magnetic field to the Sun-Planetary environment. This paper narrows its focus down to the motion and evolution of the photospheric large-scale magnetic field which affects many environments throughout this region. For this purpose we utilize a newly developed Netlogo cellular automata model. The domain of this algorithmic model is the Sun’s photosphere. Within this computational space are placed two types of entities or agents; one may refer to them as bluebirds and cardinals; the former carries outward magnetic flux and the latter carries out inward magnetic flux. One may simply call them blue and red agents. The agents provide a granularity with discrete changes not present in smooth MHD models; they undergo three processes: birth, motion, and death within the photospheric domain. We discuss these processes, as well as how we are able to develop a model that restricts its domain to the photosphere and allows the deeper layers to be considered only through boundary conditions. We show the model’s ability to mimic a number of photospheric magnetic phenomena: the solar cycle (11-year) oscillations, the Waldmeier effect, unipolar magnetic regions (e.g. sectors and coronal holes), Maunder minima, and the march/rush to the poles involving the geometry of magnetic field reversals. We also discuss why the Sun sometimes appears as a magnetic monopole, which of course requires no alteration of Maxwell’s equations.

Highlights

Magnetohydrodynamical (MHD) modeling within our SunPlanet system is fraught with difficulties due to the diversity of environments within the vast dynamical systems influenced by the Sun’s radiative and particulate emissions
We show the model’s ability to mimic a number of photospheric magnetic phenomena: the solar cycle (11-year) oscillations, the Waldmeier effect, unipolar magnetic regions, Maunder minima, and the march/rush to the poles involving the geometry of magnetic field reversals
In the current model we address the boundaries around the photosphere as follows: (1) we add active regions proportional to the Babcock-Leighton field, the North-South toroidal field they describe in their papers [4, 5], and (2) we consider the magnetic field tension from these magnetic fields to create long-range magnetic forces, which pull field entities towards the appropriate pole

Summary

Introduction

Magnetohydrodynamical (MHD) modeling within our SunPlanet system is fraught with difficulties due to the diversity of environments within the vast dynamical systems influenced by the Sun’s radiative and particulate emissions. The photospheric properties are the best observed within the Sun. Our model capitalizes on a number of the mainstays of solar physics; for example, new field entities are based upon Hale’s laws of sunspot polarities, and other features of active region fields such as Joy’s law, the Babcock-Leighton field, and so forth. We provide some sample runs with our model, thereby illustrating how our model mimics the following behaviors, as seen in the photosphere: Solar Cycle (∼11-year) Oscillations, the Waldmeier effect (large cycles are shorter than small cycles), Unipolar Magnetic Regions/Sectors/Coronal Holes (large-scale field patterns), Maunder Minima (extended periods of time where low field levels exist in the photosphere), the March/Rush to the Poles (details of polar field reversal at high latitudes), and how the Sun sometimes appears as a magnetic monopole (wherein the Sun sometimes appears to violate Maxwell’s divergence B requirement), which requires no alteration to Maxwell’s equations

Solar Field Mapping Model

Future Investigations Using This Model

Findings

Summary and Discussion