文档介绍：ic Relaxation in the Solar Corona h Miller 1, Bengt Fornberg 2, Natasha Flyer 3, & B. C. Low 4 May 1, 2008 ABSTRACT This is a mathematical study of the long-lived ic structures pro- duced in the tenuous solar corona by the turbulent, resistive relaxation of a ic ?eld under the condition of extremely high electrical conductivity. The relaxation theory of Taylor (1974), originally developed for a laboratory device, is extended to treat the open atmosphere where the relaxing ?eld must interact with its surrounding ?elds. A boundary-value problem is posed for a two dimensional model that idealizes the corona as the half Cartesian plane ?lled with a potential ?eld (i) that is anchored to a rigid, perfectly conducting base, and, (ii) that em- beds a force-free ic ?eld in the form of a ?ux rope oriented horizontally and perpendicular to the Cartesian plane. The ?ux rope has a free boundary which is an unknown in the construction of a solution for thisatmosphere. Pairs of ostatic solutions are constructed to represent the initial and ?nal states of a ?ux-rope relaxation that conserves both the total ic helicity and to- tal axial ic ?ux, using a numerical iterative method specially developed for this study. The collection of numerical solutions foundprovides an insight into the interplay among several ic propertiesin the formation of long-lived coronal structures. In particular, the study shows (i) that the outward spread of reconnection between a relaxing ?ux-rope and its external ?eld may be arrested at some outer ic ?ux-surface within which a constant-αforce-free ?eld emerges as the minimum-energy state, and, (ii) that this outward spread plicated by an inward, partial collapse of the relaxing ?ux-rope produced by a loss of internal ic pressure. Subject headings:MHD —Sun: ic ?elds —Sun: corona 1Department of Mathematics and Statistics, Wichita State University 2Department of Applied Mathematics, University of Colorado 3Institute for Mathematics Applied to the Geoscien