Fig 5. Net (top) and mean speed (bottom) for different strengths of base substrate friction γ0 and length L.
Larger MPs possess both a higher net and mean speed. The net speed reaches a maximum for a medium base friction coefficient of γ0 = 6 × 10−6 kg/s while the mean speed increases with decreasing friction. There is a critical length of Lcr ≈ 120 μm in the model and L needs to be larger than Lcr to transition from global calcium oscillations to states with motion of the boundaries. This is in qualitative agreement with the linear stability analysis that predicts the transition to an oscillatory short-wavelength instability (green line, bottom) at 130 μm for γ0 = 6 × 10−6 kg/s. Parameters: B = 3.5, vslip = 2.5 μm/s, α = 0.15 and F = 12.3.