Probability distribution of the location angle λ (left panels) and the corresponding axis shape (right panels) for the elliptical model of the flux rope axis (defined in Fig. 7). Since the model is symmetric, so that only the part λ > 0 is shown. The distributions are normalized so that the integral of is unity. Five cases with different values of the aspect ratio (b/a) of the ellipse are shown with solid curves, for two maximum extension ϕ_max of the angle ϕ (defined in Fig. 7). The dotted curve represents the distribution for a circular front and low ϕ_max values (cosinus function, see Sect. 3.3).