CHAOS IN A RESONANTLY KICKED OSCILLATOR

We study, in detail, the structure of the stochastic layer of a resona ntly kicked oscillator. For the resonantly kicked case the stochastic layer has a crystalline or quasicrystalline structure depending on the parameter omega(0) tau = 2 pi n/m, where tau is the kicking period, 2 pi/omega(0) the natural period of the oscillator and n and m are inte gers. For this resonant case we obtain the underlying orbit structure and the exact mechanism responsible for the diffusion in phase space i s established. The diffusion of orbits in the stochastic layer is exam ined and a general universal form for the diffusion coefficient obtain ed.