Fig. 5.

Mean speed versus ϵ for a Gaussian threshold distribution. c̅ as a function of ϵ for $h_0=0.3$. Solid curve: (24); circles: from averaging (21) over 1000 realisations per point. Equation (9) was truncated after 50 terms per sum. Other parameter values are $\kappa =5$, ${\sigma }^2=0.2$, $L=100$