Abstract
In our recent paper (Nuovo Cimento B, 114 (1999) 31), the linear stability of a family of periodic solutions was studied for the following model: (z) double over dot + omega(0)(2)(1 + epsilon sin(Omegat))z + epsilon z\z\(2) Sigma(n=-infinity)(infinity) cos(nt) = 0, epsilon much less than 1, z epsilon C. In this work we corroborate the found periodic orbits by means of a chaos control. Their existence may be in doubt because they emerged from a perturbative analysis which actually was performed up to first order in epsilon. For the examples considered, chaos control establishes the existence of the periodic orbits found over a comparatively large time interval, provided epsilon less than or equal to 0.001. Both linearly stable and unstable periodic orbits arising from the perturbative method are considered. In the latter case, we identify a chaotic regime from calculating the largest Lyapunov exponent and the power spectrum.