Behaviour of the function as defined in Eq. (68), for various values of the number of particles. The prefactor has been added so as to mask Poisson shot noise, allowing the initial values of to be independent of N. It illustrates the bifurcation between the initial Balescu-Lenard collisional evolution, for which low values of Σ₂ are expected and the collisionless Vlasov evolution for which the system is no more axisymmetric leading to larger values of Σ₂. As expected, the larger the number of particles, the later the transition.