171 research outputs found
Diffusion and escape times in the open-leaky standard map
We study the connection between transport phenomenon and escape rate statistics in two-
dimensional standard map. For the purpose of having an open phase space, we let the momentum
co-ordinate vary freely and restrict only angle with periodic boundary condition. We also define
a pair of artificial holes placed symmetrically along the momentum axis where the particles might
leave the system. As a consequence of the leaks the diffusion can be analysed making use of only
the ensemble of survived particles. We present how the diffusion coefficient depends on the size and
position of the escape regions. Since the accelerator modes and, thus, the diffusion are strongly
related to the system’s control parameter, we also investigate effects of the perturbation strength.
Numerical simulations show that the short-time escape statistics does not follow the well-known
exponential decay especially for large values of perturbation parameters. The analysis of the escape
direction also supports this picture as a significant amount of particles skip the leaks and leave the
system just after a longtime excursion in the remote zones of the phase space
Szoftverfejlesztés Java környezetben
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