Chaotic synchronization of coupled electron-wave systems with backward   waves
  The chaotic synchronization of two electron-wave media with interacting backward waves and cubic phase nonlinearity is investigated in the paper. To detect the chaotic synchronization regime we use a new approach, the so-called time scale synchronization [Chaos, 14 (3) 603-610 (2004)]. This approach is based on the consideration of the infinite set of chaotic signals' phases introduced by means of continuous wavelet transform. The complex space-time dynamics of the active media and mechanisms of the time scale synchronization appearance are considered. 
Alexander E. Hramov, Alexey A. Koronovskii, Pavel V. Popov, and Irene   S. Rempen