The topological behaviour of stable magnetic separators

It is important to understand the complex topology of the magnetic field in the solar corona in order to be able to comprehend the mechanisms which gi ve rise to phenomena such as coronal loop structures and x-ray bright point s. A key feature of the magnetic topology is a separator. A magnetic separa tor is a field line which connects two magnetic null points, places where t he magnetic field becomes zero. A stable magnetic separator is important as it is the intersection of two separatrix surfaces. These surfaces divide t he magnetic field lines into regions of different connectivity, so a separa tor usually borders four regions of field-line connectivity. This work exam ines the topological behaviour of separators that appear in a magnetic fiel d produced by a system of magnetic sources lying in a plane (the photospher e). The questions of how separators arise and are destroyed, the topologica l conditions for which they exist, how they interact and their relevance to the coronal magnetic field are addressed.