Evolution of Model L1. Left column: magnetic field lines; red and blue field lines are tied to opposite footpoints of the twisted loop; yellow lines denote ambient field. Middle column: temperature distribution; yellow patchy surface corresponds to 2 MK; orange and blue surfaces correspond to 3 and 4 MK, respectively. Right column: surfaces of j = j_crit, i.e. showing the locations with fast magnetic energy release. Times (after onset of the instability) are shown for each row on the left in units of characteristic Alfvén times t_A, which are 0.44 s for this model.