Fermi acceleration and its suppression in a time-dependent Lorentz gas

Some dynamical properties for a Lorentz gas were studied considering both static and time-dependent boundaries. For the static case, it was confirmed that the system has a chaotic component characterized with a positive Lyapunov exponent. For the time-dependent perturbation, the model was described...

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Veröffentlicht in:Physica. D 2011-02, Vol.240 (4), p.389-396
Hauptverfasser: Oliveira, Diego F.M., Vollmer, Jürgen, Leonel, Edson D.
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Sprache:eng
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Zusammenfassung:Some dynamical properties for a Lorentz gas were studied considering both static and time-dependent boundaries. For the static case, it was confirmed that the system has a chaotic component characterized with a positive Lyapunov exponent. For the time-dependent perturbation, the model was described using a four-dimensional nonlinear map. The behaviour of the average velocity is considered in two different situations: (i) non-dissipative and (ii) dissipative dynamics. Our results confirm that unlimited energy growth is observed for the non-dissipative case. However, and totally new for this model, when dissipation via inelastic collisions is introduced, the scenario changes and the unlimited energy growth is suppressed, thus leading to a phase transition from unlimited to limited energy growth. The behaviour of the average velocity is described using scaling arguments. ► Time dependent Lorentz Gaz where the boundary moves according to a periodic function. ► The phenomenon of Fermi Acceleration is present and the average velocity for an ensemble of particles grows as a power law. ► Suppression of Fermi acceleration when inelastic collisions are introduced. ► Scaling function with well defined critical exponents.
ISSN:0167-2789
1872-8022
DOI:10.1016/j.physd.2010.09.015