Fig. 3

Instantaneous speed of a travelling front for a Gaussian threshold distribution. Measured front speed for a Gaussian threshold distribution, extracted from a simulation of (3) (blue); theoretical value from (21) (red); and the threshold (4) (green), for \(\kappa =5\) (top) and \(\kappa =30\) (bottom). Equation (9) was truncated after 50 terms per sum. Other parameter values are \(\sigma^{2}=1/\kappa\), \(h_{0}=0.3\), \(\epsilon =0.01\), \(L=100\)