Departamento de Física, Universidade Federal do Paraná, 81531-980 Curitiba, PR, Brazil
Copyright © 2009 Cesar Manchein and Marcus W. Beims. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Ac-driven asymmetric pulses
can be used to control the Fermi
acceleration between three different
motions, : the accelerated mode, : the decelerated mode, and : the hyperaccelerated mode. In this paper we show that dissipation strongly affects the particles velocity, reducing the possibility for an accurate control of the dynamics. The saturation time, where the mean velocity starts to be constant due to dissipation, decays with a power law , where is the dissipation parameter and
is close to 1. The value of the saturated mean velocity also decays with a power law with exponent
0.6 for case , and 0.3 for case . In case this velocity is almost constant for small dissipations.