Schematic representation of the considered configuration. Three magnetic strands are shown. The cyan Gaussian pulses are excited at time t = 0 at z = z₀ on all strands simultaneously. On each strand, the pulses propagate at a different speed, first to the blue line and then the purple line. The resultant observed intensity, as integrated over the different strands, is given by the red line, which shows the multithermal apparent damping and broadening.