  A new so-called `gravitational loss-cone instability' in stellar systems has
recently been investigated theoretically in the framework of linear
perturbation theory and proved to be potentially important in understanding the
physical processes in centres of galaxies, star clusters, and the Oort comet
cloud. Using N-body simulations, we confirm previous findings and go beyond the
linear theory. Unlike the well-known instabilities, the new one shows no
notable change in spherical geometry of the cluster, but it significantly
accelerates the speed of diffusion of particles in phase space leading to a
repopulation of the loss cone and early instability saturation.
