T.I.R.E.S. (Innovative Technologies for Signal Detection and Processing)–Università di Bari;

In this paper we describe the beam distribution in particle accelerators in the framework of a stochastic–hydrodynamic scheme. In this scheme the possible reproduction of the halo after its elimination is a consequence of the stationarity of the transverse distribution which plays the role of an attractor for every other distribution. The relaxation time toward the halo is estimated, and a few examples of controlled transitions toward a permanent halo elimination are discussed. 1