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arXiv 1208.6547astro-ph.COgr-qchep-phhep-th
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宇宙学欧姆定律与非最小电磁动力学

Cosmological Ohm's law and dynamics of non-minimal electromagnetism

Lukas Hollenstein, Rajeev Kumar Jain, Federico R. Urban

摘要:

宇宙结构和星系际介质中大尺度磁场的起源仍然知之甚少。我们探讨了非最小电磁耦合对电流和磁场宇宙演化的影响。在这种情况下,我们重新审视温和的非线性等离子体动力学周围的重组,已知产生弱磁场。我们使用协变的方法来获得一个完全通用的和非线性的等离子体电流的演化方程,并推导出一个广义欧姆定律有效的大尺度上,以及在存在非最小耦合宇宙(伪)标量场。由于相当大的等离子体的导电性和严格的观测界限,这样的耦合,我们得出结论,修改的标准(绝热)演变的磁场在这些情况下是非常有限的。即使在远远超过百万分之一秒的尺度上,任何偏离通量冻结行为的行为都受到抑制。

英文摘要:

The origin of large-scale magnetic fields in cosmic structures and the intergalactic medium is still poorly understood. We explore the effects of non-minimal couplings of electromagnetism on the cosmological evolution of currents and magnetic fields. In this context, we revisit the mildly non-linear plasma dynamics around recombination that are known to generate weak magnetic fields. We use the covariant approach to obtain a fully general and non-linear evolution equation for the plasma currents and derive a generalised Ohm law valid on large scales as well as in the presence of non-minimal couplings to cosmological (pseudo-)scalar fields. Due to the sizeable conductivity of the plasma and the stringent observational bounds on such couplings, we conclude that modifications of the standard (adiabatic) evolution of magnetic fields are severely limited in these scenarios. Even at scales well beyond a Mpc, any departure from flux freezing behaviour is inhibited.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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