Illustration of the initial configuration of two magnetic topologies potentially linked to hot loops. Panel a: a magnetic feature (blue patch) of one polarity embedded in a predominantly unipolar magnetic environment of the opposite polarity (red patches) at one footpoint of the loop. The expected magnetic connectivity is indicated by black curves. The sphere indicates null point, the potential site of reconnection in this type of magnetic configuration. The long and short dotted curves are magnetic field lines that lie above and below the null point. The segment overlying the null point then represents a seemingly simple hot loop with two footpoints. Panel b: magnetic topology of a complex hot loop system is displayed. An emerging or cancelling magnetic bipole (smaller red and blue patches) reconnects with the overlying magnetic field and leads to the formation of a hot loop connecting two larger magnetic patches or footpoints. See Sect. 4.1 for discussion.