标题： 恒星内部环形磁场的稳定性 显示英文标题

标题： Stability of toroidal magnetic fields in stellar interiors

摘要： 我们进行了纯环形和环形-极向混合磁场配置的三维MHD模拟，以研究泰勒不稳定性的行为。 首次同时考虑了旋转和磁扩散的共同作用，并包含了极向场对不稳定环形磁场动态演化的影响。 在没有扩散的情况下，快速旋转（旋转速率与阿尔芬频率相比）能够在旋转轴和磁场轴对齐且径向场强梯度p < 1.5时抑制不稳定性。 当包含扩散时，该系统在扩散主导和临界扩散主导区域变得不稳定。 如果磁场轴和旋转轴相互垂直，科里奥利力引起的稳定效应是尺度相关的，并随着波数的增加而减小。 在径向场梯度大于p > 1.5的环形场中，快速旋转不能抑制不稳定性，而是引入一个阻尼因子到增长率中，这与分析预测一致。 对于混合极向-环形场，我们在非轴对称模态的稳定性阈值处发现了一个不稳定的轴对称模态，这是分析上未预测的；有人认为轴对称模态对于泰勒-斯普雷特发电机环的闭合是必要的。 显示英文摘要

摘要： We present 3D MHD simulations of purely toroidal and mixed poloidal-toroidal magnetic field configurations to study the behavior of the Tayler instability. For the first time the simultaneous action of rotation and magnetic diffusion are taken into account and the effects of a poloidal field on the dynamic evolution of unstable toroidal magnetic fields is included. In the absence of diffusion, fast rotation (rotation rate compared to Alfv\'en frequency) is able to suppress the instability when the rotation and magnetic axes are aligned and when the radial field strength gradient p < 1.5. When diffusion is included, this system turns unstable for diffusion dominated and marginally diffusive dominated regions. If the magnetic and rotation axes are perpendicular to each other the stabilizing effect induced by the Coriolis force is scale dependent and decreases with increasing wavenumber. In toroidal fields with radial field gradients bigger than p > 1.5, rapid rotation does not suppress the instability but instead introduces a damping factor to the growth rate in agreement with the analytic predictions. For the mixed poloidal-toroidal fields we find an unstable axisymmetric mode, not predicted analytically, right at the stability threshold for the non-axisymmetric modes; it has been argued that an axisymmetric mode is necessary for the closure of the Tayler-Spruit dynamo loop.