PERIODIC NONSINGULAR INVARIANT SERIES FOR PERIODIC PERTURBATIONS OF AUTONOMOUS ONE-DEGREE-OF-FREEDOM HAMILTONIANS

For periodic perturbations of autonomous 1D Hamiltonians, to all order s in powers of the perturbation parameter, non-singular invariant seri es periodic in the independent variable are constructed. In applicatio ns to magnetohydrodynamic equilibria, the non-singularity has allowed magnetic island structure to be represented within the framework of a perturbation treatment. (C) 1997 Elsevier Science B.V.