Kinematic statistics of the 32 shock waves. Panels a and b are the same as panels a and b in Fig. 4, but instead for radial speed, V_R, and lateral speed, V_L. Panel c: A_R, max as a function of V_R, max for 25 shock waves (on 32) presenting a visible acceleration phase. Each point of colour represents a different event. The yellow line corresponds to the best fit obtained from these data.