Figure 4. Velocity selection in the bundle.

(a) Profiles of the functions $g(y)$ and $h(y)$, both of which go monotonically from 0 to 1 as $y$ goes from 0 to +∞. (b) Graphical illustration of the velocity selection condition Equation 4 as the intersection between two curves. The blue curve represents the left-hand side of Equation 4, and the black lines represent three possible parameter regimes for the right-hand side (here b = 0.27 and a = 0.1, 0.7 and 1.3 from left to right). Solid (open) circles represent stable (unstable) solutions. (c) Phase diagram presenting these three regimes as a function of parameters $a$ and $b$. (d) Values of the rescaled apparent filament velocity $u$ selected by the system, with colors indicating the stability of the solutions. The phase diagram of panel (c) is reproduced on the bottom face of the plot to facilitate comparisons.