A revised flux vector for the collisional evolution of Keplerian orbits

In statistical Keplerian systems the disordered component of collisionally induced motion of matter introduces new terms into the flux vector. This contribution, which is calculated from a transport equation, tends to reduce the density gradient and causes the expansion which is observed in computer simulations of collisional systems. A quantitative comparison with Trulsen's (1972) simulations confirms the revised expression of the flux vector. (Auth.)