STOCHASTIC CHARACTRISTICS OF MAGNETIC FIELD LINE IN TOKAMAK
Tokamak中磁力线的随机特性

Under the cylindrical approximation, we apply nonlinear Hamiltonian oscilation theory to investigate the process of transition of perturbed equilibrium magnetic field to randomness. The results show that perturbed magnetic hamiltonian is only rela-ted to the radial perturbation of magnetic field, the magnetic field line takes the form of regular magnetic island under a single mode perturbation. The overla-pping criterion for magnetic field to enter the random state is given for the case of existence of two mode action, and the relation of points on the poincare section is reduced to a kind of standard mapping under special multimode perturbation.