Magneto-elastic equilibrium of a neutron star crust
Magneto-elastic equilibrium of a neutron star crust
复制标题
DOI：
10.1093/mnras/stab1848
复制
发表时间：
2021-06
影响因子：
4.8
通讯作者：
Y. Kojima;S. Kisaka;K. Fujisawa
中科院分区：
文献类型：
--
作者：
Y. Kojima;S. Kisaka;K. Fujisawa
我们研究磁化中子星外壳的平衡。我们计算了轴对称模型，其中弹性力平衡由洛伦兹力驱动的螺线线运动。考虑弹性剪切变形，可以建立多种平衡模型；此外，也有环面磁场主导的模型。这些结果与正压流体恒星的结果明显不同。我们论证了一些磁能超过弹性能的模型。这种过剩来自于这样一个事实，即大量的磁能与磁力的非旋转部分有关，这与重力和压力是平衡的。对于平衡模型来说，用弱弹性力平衡小螺线管部分就足够了。我们发现地壳的弹性对磁场约束起着重要的作用。此外，我们给出了弹性极限剪应力的空间分布，从而可以识别地壳破裂的位置。这一结果对实际的地壳地震模型具有重要意义。
We examine the equilibrium of a magnetized neutron star crust. We calculate axially symmetric models in which an elastic force balances solenoidal motion driven by a Lorentz force. A large variety of equilibrium models are allowed by incorporating the elastic shear deformation; in addition, toroidal-magnetic-field-dominated models are available. These results remarkably differ from those in barotropic fluid stars. We demonstrate some models wherein the magnetic energy exceeds the elastic energy. The excess comes from the fact that a large amount of magnetic energy is associated with the irrotational part of the magnetic force, which is balanced with gravity and pressure. It is sufficient for equilibrium models that the minor solenoidal part is balanced by a weak elastic force. We find that the elasticity in the crust plays an important role on the magnetic field confinement. Further, we present the spatial distribution of the shear stress at the elastic limit, by which the crust-fracture location can be identified. The result has useful implications for realistic crust-quake models.