Structure And Dynamics Of The Coronal Magnetic Field

The last few years have seen a marked increase in the sophistication of models of the solar corona. This has been brought about by a confluence of three key elements. First, the collection of high-resolution observations of the Sun, both in space and time, has grown tremendously. The SOHO (Solar Heliospheric Observatory) mission is providing additional correlated high-resolution magnetic, white-light and spectroscopic observations. Second, the power and availability of supercomputers has made two- and three-dimensional modeling routine. Third, the sophistication of the models themselves, both in their geometrical realism and in the detailed physics that has been included, has improved significantly. The support from our current Space Physics Theory grant has allowed us to exploit this confluence of capabilities. We have carried out direct comparisons between observations and models of the solar corona. The agreement between simulated coronal structure and observations has verified that the models are mature enough for detailed analysis, as we will describe. The development of this capability is especially timely, since observations obtained from three space missions that are underway (Ulysses, WIND and SOHO) offer an opportunity for significant advances in our understanding of the corona and heliosphere. Through this interplay of observations and theory we can improve our understanding of the Sun. Our achievements thus far include progress modeling the large-scale structure of the solar corona, three-dimensional models of active region fields, development of emerging flux and current, formation and evolution of coronal loops, and coronal heating by current filaments. VanHoven, Gerard and Schnack, Dalton D. Goddard Space Flight Center NAG5-2257...

Magnetism defines the complex and dynamic solar corona. It determines the magnetic loop structure that dominates images of the corona, and stores the energy necessary to drive coronal eruptive phenomena and flare explosions. At great heights the corona transitions into the ever-outflowing solar wind, whose speed and three-dimensional morphology are controlled by the global coronal magnetic field. Coronal magnetism is thus at the heart of any understanding of the nature of the corona, and essential for predictive capability of how the Sun affects the Earth. Coronal magnetometry is a subject that requires a concerted effort to draw together the different strands of research happening around the world. Each method provides some information about the field, but none of them can be used to determine the full 3D field structure in the full volume of the corona. Thus, we need to combine them to understand the full picture. The purpose of this Frontiers Research Topic on Coronal Magnetometry is to provide a forum for comparing and coordinating these research methods, and for discussing future opportunities.

These are the Proceedings of the Yohkoh 10th Anniversary Meeting, a COSPAR Colloquium held in Kona, Hawaii, USA, on January 20-24, 2002. The title of the meeting was Multi-Wavelength Observations of Coronal Structure and Dynamics. In these proceedings the many and varied advances of the dynamics solar atmosphere in the past ten years of observations by Yohkoh have been reviewed.

Magnetism defines the complex and dynamic solar corona. It determines the magnetic loop structure that dominates images of the corona, and stores the energy necessary to drive coronal eruptive phenomena and flare explosions. At great heights the corona transitions into the ever-outflowing solar wind, whose speed and three-dimensional morphology are controlled by the global coronal magnetic field. Coronal magnetism is thus at the heart of any understanding of the nature of the corona, and essential for predictive capability of how the Sun affects the Earth. Coronal magnetometry is a subject that requires a concerted effort to draw together the different strands of research happening around the world. Each method provides some information about the field, but none of them can be used to determine the full 3D field structure in the full volume of the corona. Thus, we need to combine them to understand the full picture. The purpose of this Frontiers Research Topic on Coronal Magnetometry is to provide a forum for comparing and coordinating these research methods, and for discussing future opportunities.

The book covers intimately all the topics necessary for the development of a robust magnetohydrodynamic (MHD) code within the framework of the cell-centered finite volume method (FVM) and its applications in space weather study. First, it presents a brief review of existing MHD models in studying solar corona and the heliosphere. Then it introduces the cell-centered FVM in three-dimensional computational domain. Finally, the book presents some applications of FVM to the MHD codes on spherical coordinates in various research fields of space weather, focusing on the development of the 3D Solar-InterPlanetary space-time Conservation Element and Solution Element (SIP-CESE) MHD model and its applications to space weather studies in various aspects. The book is written for senior undergraduates, graduate students, lecturers, engineers and researchers in solar-terrestrial physics, space weather theory, modeling, and prediction, computational fluid dynamics, and MHD simulations. It helps readers to fully understand and implement a robust and versatile MHD code based on the cell-centered FVM.