Tokamak中磁力线的随机特性

在直柱近似下，运用哈密顿非线性振荡系统理论研究了平衡态磁场在磁扰动下进入随机状态的过程．结果表明：一阶扰动哈密顿量仅与径向扰动磁场有关；在单模扰动下，磁力线呈规则磁岛结构；在双模扰动下，给出了磁力线进入随机态的重叠判据；在特定多模优动下，将Ｐｏｉｎｃａｒé截面上点演化关系化为一类标准映象。 关键词：

STOCHASTIC CHARACTRISTICS OF MAGNETIC FIELD LINE IN TOKAMAK

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.