Maps of temperature (top row), and Si IV 1402 Å emissivity (bottom row) from our numerical simulation reveal very fast thermal evolution and accompanying increase in Si IV 1402 Å intensity along already existing spicules. The time interval between the snapshots is only 10 s. The dashed ovals highlight the increased Si IV emission that is associated with the propagation and dissipation of electrical currents and subsequent heating of threads in the spicule. These threads cause the almost vertical bright features (dashed white ovals) in Figure 2. The two animations show (a) the temporal evolution of the figure and (b) blinking the temperature and Si IV 1402 Å emissivity plots.

(Animations (a) and (b) of this figure are available.)

The video/animation of this figure is available in the online journal.