Model tracks of fiber busts on dynamic spectra. The basic model (black line in all plots) is for B₀ = 16 G, r = 120 Mm, f_w = 6 MHz, B_t = 2 G and a fourfold Newkirk density model. Left panel: effect of B₀, which is 8 G for the blue line and 24 G for the red line, middle panel: effect of the loop radius, which is 90 Mm (blue line) and 150 Mm (red line) and right panel effect of f_w, which is 3 MHz for the blue line and 8 MHz for the red. Thick lines denote the region for which 0.25 <  x <  0.5. Horizontal dashed lines mark the limits of the SAO frequency range.