Left panel: vertical magnetic field strength at height z = 0 Mm for timestep t = 5000 s. The color bar range is [–1.5 kG, +1.5 kG]. A set of magnetic field lines connecting the main magnetic polarities is overplotted in yellow in the left panel. Field line apices and cork positions of corks with T = 10⁵ K are indicated by blue and red crosses. These field lines are further discussed in Sect. 4.4. Right panel: temperature distribution of the simulation grid points as a function of height for timestep t = 5000 s of the simulation. The average temperature at a given height is indicated by the gray line.