Fermi acceleration in rotating drums

Abstract

Consider hard balls in a bounded rotating drum. If there is no gravitation, then there is no Fermi acceleration, i.e., the energy of the balls remains bounded forever. If there is gravitation, Fermi acceleration may arise. A number of explicit formulas for the system without gravitation are given. Some of these are based on an explicit realization, which we derive, of the well-known microcanonical ensemble measure.

Billiard in a rotating half-plane: modeling and dynamics

“…Observe that the unboundedness of the rod is the reason for the ball to speed up infinitely. This is the principal difference of the current result and, for instance, that of the paper [3] where the velocities of particles are bounded. However, in some cases (see, for example, [26]), the billiard in a bounded domain with moving boundary may cause motions with exponentially increasing velocities.…”