In this review, our present day understanding of global magnetic fields on the Sun and other stars has been discussed from both observational and theoretical viewpoints. For the Sun, we now have long-running data sets of global magnetic activity. For other stars, we are just beginning to learn of the wide variety of magnetic morphologies that exist. In terms of theoretical models, recent years have seen a significant advance in global modeling techniques. Global magnetic fields may be modeled under the nonlinear force-free approximation for long periods of time, or for short periods of time using highly detailed MHD models. A key feature of these models is that they have been validated through various comparisons with observations. While our understanding has significantly increased over the last decade, there are several immediate outstanding issues. Five of these are discussed below, where the list is not exhaustive and the order in no way reflects their importance.
These issues may be addressed with the current suite of ground and space-based observatories along with developing new theoretical techniques. A key element in achieving this goal is the increasing computing power available both for real-time data reduction and for theoretical modeling. Future revisions of the article will hopefully describe answers to some of these questions. Along with answering these questions, the scope of the review in future revisions will also be increased to include additional topics such as: the connection between the Sun and Heliosphere, observations of coronal and solar prominence magnetic fields, global eruptive models and a fuller discussion of the consequences of observational limitations on the models which directly employ observations.
Living Rev. Solar Phys. 9, (2012), 6
This work is licensed under a Creative Commons License.