Size of the heating region as a function of time for three different threshold values. The highest heating rates take place in small and localised regions in the neighbourhood of the dislocation. Transverse sizes of 1–2 arcsec (making the area circular for simplicity) are heated. These heated regions propagate along the wave path, both because of phase speed and because of the increased thermal conductivity along field lines. In time, a thin and long region is heated, resembling bright coronal loops inside the large magnetic flux tube.