Magnetic Field Generation in Stars
Magnetic Field Generation in Stars
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DOI：
10.1007/s11214-015-0138-y
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发表时间：
2015-03
影响因子：
10.3
通讯作者：
L. Ferrario;A. Melatos;J. Zrake
中科院分区：
文献类型：
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作者：
L. Ferrario;A. Melatos;J. Zrake
从主序星（特别是MiMeS、MAGORI和BOB巡天）到致密天体，在观测恒星磁性方面已经取得了巨大进展。最近的数据使恒星磁场的起源这一棘手问题变得更加清晰，这是天体物理学中尚未解决的主要问题之一。在本章中，我们回顾了这一研究领域的最新工作。特别是，我们着眼于化石场假说，它将致密恒星的磁性与主序星和前主序星的磁性联系起来，我们考虑为什么它的可行性现在受到质疑，特别是在高磁性白矮星的背景下。我们还回顾了化石与发电机在中子星背景下的争论，以及浮力、螺旋度和超流体湍流等关键物理过程在中子星场的产生和稳定中所起的作用。关于中子星内部磁场的独立信息将来自未来的引力波探测。用激光干涉仪引力波天文台（LIGO）对蟹状脉冲星的相干搜索已经将其引力波光度限制在观测到的自旋向下光度的约2%，从而将内部场的极限设定为约1016G。从循环脉冲星推断出的间接自旋下降极限也产生了有趣的引力波相关约束。因此，我们可能正处于一个令人兴奋的新时代的黎明，在一个新的非电磁观测窗口的开启下，我们将发现致密恒星的磁性。我们还回顾了磁流体动力学湍流理论和计算的最新进展，因为它适用于恒星磁学和发电机理论。这些进展提供了对恒星发电机的作用以及控制恒星中扩散磁通量传输的过程的见解。
Enormous progress has been made on observing stellar magnetism in stars from the main sequence (particularly thanks to the MiMeS, MAGORI and BOB surveys) through to compact objects. Recent data have thrown into sharper relief the vexed question of the origin of stellar magnetic fields, which remains one of the main unanswered questions in astrophysics. In this chapter we review recent work in this area of research. In particular, we look at the fossil field hypothesis which links magnetism in compact stars to magnetism in main sequence and pre-main sequence stars and we consider why its feasibility has now been questioned particularly in the context of highly magnetic white dwarfs. We also review the fossil versus dynamo debate in the context of neutron stars and the roles played by key physical processes such as buoyancy, helicity, and superfluid turbulence, in the generation and stability of neutron star fields.Independent information on the internal magnetic field of neutron stars will come from future gravitational wave detections. Coherent searches for the Crab pulsar with the Laser Interferometer Gravitational Wave Observatory (LIGO) have already constrained its gravitational wave luminosity to be ≲2 % of the observed spin-down luminosity, thus placing a limit of ≲1016G on the internal field. Indirect spin-down limits inferred from recycled pulsars also yield interesting gravitational-wave-related constraints. Thus we may be at the dawn of a new era of exciting discoveries in compact star magnetism driven by the opening of a new, non-electromagnetic observational window.We also review recent advances in the theory and computation of magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo theory. These advances offer insight into the action of stellar dynamos as well as processes which control the diffusive magnetic flux transport in stars.