ANOMALOUS LYAPUNOV SPECTRUM IN GLOBALLY COUPLED OSCILLATORS

Numerical experiments of a globally coupled oscillator system show tha t one type of collective chaos of high dimension has discrete and cont inuous parts in its Lyapunov spectrum. This occurs in a scattered stat e, i.e., a state in which no two oscillators behave identically. It is argued from a consideration of the phase space structure that the dis crete exponents are related to, in a sense, the macroscopic dynamics, while the continuous part reflects the microscopic dynamics. This type of high-dimensional chaos is compared to a second type possessing an apparently continuous part only. Preceding the appearance of the first type, we found a sequence of bifurcations of collective low-dimension al behavior in scattered states, and their investigation reveals the r oute to the first type of the high-dimensional chaos.