A class of topological magnetic island bifurcations that has not previously been observed in toroidal plasmas is described. Increasing an externally applied three-dimensional magnetic field in resistive magnetohydrodynamic simulations results in the asymmetric elongation of resonant island flux surfaces followed by a sequence of heteroclinic bifurcations. These bifurcations produce new sets of hyperbolic-elliptic fixed points as predicted by the Poincaré-Birkoff fixed point theorem. Field line calculations verify that the new fixed points do not connect to those of the prebifurcated islands as required for heteroclinic bifurcations on a torus with winding numbers composed of common integer factors.

中文翻译：

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等离子体对共振磁扰动的响应的磁流体动力学模拟中的非斜面分叉观测

描述了以前在环形等离子体中未观察到的一类拓扑磁岛分叉。在电阻磁流体动力学模拟中增加外部施加的三维磁场会导致共振岛磁通量表面的不对称伸长，随后是一系列的异斜分叉。正如Poincaré-Birkoff不动点定理所预测的那样，这些分歧产生了新的双曲椭圆不动点集。磁力线计算证实，新的不动点不与环上由常见整数因子组成的圆环上的异斜分叉所要求的预分叉岛相连接。