Periodic compression of an adiabatic gas: Intermittency enhanced Fermi acceleration

A gas of noninteracting particles diffuses in a lattice of pulsating scatterers. In the finite horizon case with bounded distance between collisions and strongly chaotic dynamics, the velocity growth (Fermi acceleration) is well described by a master equation, leading to an asymptotic universal non-Maxwellian velocity distribution scaling as v ~ t. The infinite horizon case has intermittent dynamics which enhances the acceleration, leading to v ~ t ln t and a non-universal distribution.
Comment: 6 pages, 4 figures, to appear in EPL (http://epljournal.edpsciences.org/)