Magnetic field structure due to the global velocity field in spiral galaxies
Magnetic field structure due to the global velocity field in spiral galaxies
复制标题
螺旋星系中整体速度场引起的磁场结构
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
F. Stasyszyn
中科院分区：
文献类型：
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作者：
H. Kotarba;H. Lesch;K. Dolag;T. Naab;Peter H. Johansson;F. Stasyszyn
我们提出了一套全球性的，自洽的N体/光滑粒子流体动力学（SPH）模拟的动态演化的星系盘气体，包括磁场。我们在Vine代码的SPH部分中使用理想感应方程实现了一个描述来跟踪磁场的演变。场方程的直接实现的结果进行了比较，由欧拉势，这构成了一个无约束的描述，一个约束不满足直接实现的表示。将所有模拟与小工具代码中的磁场实现进行比较，该小工具代码还包括用于X·B的清洁方法。
从一个均匀的种子场，我们发现，通过微分旋转和螺旋结构的形成的磁盘的字段被放大了一个数量级内的五个旋转周期的磁盘。对于更高的数值分辨率，放大更强。此外，在我们的模拟中，我们发现磁场结构与星系的密度模式有着紧密的联系，磁场线与气体的发展螺旋模式对齐。我们的模拟清楚地表明了非轴对称的磁场演化的重要性。
We present a set of global, self-consistent N-body/smoothed particle hydrodynamic (SPH) simulations of the dynamic evolution of galactic discs with gas, including magnetic fields. We have implemented a description to follow the evolution of magnetic fields with the ideal induction equation in the SPH part of the vine code. Results from a direct implementation of the field equations are compared to a representation by Euler potentials, which pose a ∇·B-free description, a constraint not fulfilled for the direct implementation. All simulations are compared to an implementation of magnetic fields in the gadget code which also includes cleaning methods for ∇·B.
Starting with a homogeneous seed field, we find that by differential rotation and spiral structure formation of the disc the field is amplified by one order of magnitude within five rotation periods of the disc. The amplification is stronger for higher numerical resolution. Moreover, we find a tight connection of the magnetic field structure to the density pattern of the galaxy in our simulations, with the magnetic field lines being aligned with the developing spiral pattern of the gas. Our simulations clearly show the importance of non-axisymmetry for the evolution of the magnetic field.
影响因子：
1.3
作者：
R. Wielebinski
通讯作者：
R. Wielebinski