I study the expansion process of emerging flux tubes in the solar atmosphere (Figure 6). The aim of this study is to investigate the physical mechanism of those solar phenomena related to emerging flux tubes, such as tiny bipoles, arch filament systems, sunspots, filaments, X-ray brightenings, coronal mass ejections, and the sigmoid strucuture of coronal arcades. The following two animations are based on a 2.5-dimensional MHD simulation (Magara 2001).
Magara, T. 2001 ApJ, 549, 608
Evolution of an emerging flux tube
Emergence of magnetic field lines
Color map: normal component of magnetic field on the surface