Big Entropy Fluctuations in Statistical Equilibrium: The Fluctuation Law

The structure of very complicated irregular "microscopic" (local) entropy fluctuations around a big separated "macroscopic" (global) fluctuation in the statistical equilibrium was studied in numerical experiments on a simple 2--freedom strongly chaotic Hamiltonian model described by the modified Arnold cat map. A comparison of transient nonequilibrium rise and relaxation process of the big fluctuation out of the statistical equilibrium with a nonequilibrium steady state in a model without statistical equilibrium is considered and discussed with respect to the so-called Fluctuation Law (or "theorem") introduced and intensively studied recently in the latter case. A new transient fluctuation law was found on the basis of a simple semiempirical theory developed. Preliminary results of numerical experiments on some fractal properties of the "microscopic" fluctuations are presented and briefly discussed.