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arXiv 2011.08245gr-qc
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梅尔文的“磁性宇宙”,磁张力的作用和对引力坍缩的影响

Melvin's "magnetic universe", the role of the magnetic tension and the implications for gravitational collapse

Christos G. Tsagas, Panagiotis Mavrogiannis

摘要:

电磁学似乎有可能改变相对论引力坍缩的命运。例如,库仑力原则上可以防止带电物质最终坍缩成奇点。同样,半个世纪前,梅尔·梅尔文注意到磁力不会在自己的引力下坍缩,不管后者有多强。相反,磁场似乎能够稳定自身,对抗重力自收缩。梅尔文对此很感兴趣,他想知道磁性是否也能抵抗带电物质的实际坍缩。在这里,我们通过两个互补的情景来回顾这些问题。第一个重新考虑梅尔文高度理想化的“磁宇宙”,并得出相同的结论,即磁场不自引力。第二种是真实的坍缩场景,就像磁化的大质量致密恒星那样。寻找梅尔文问题的答案,我们发现磁场确实显示出一种普遍的倾向,以支持反对相对论引力坍缩。这里讨论的磁效应涉及到宿主空间的曲率,随着坍缩的进行,它会变得更强,而触发因素是场的张力。换句话说,原因在于磁力线的弹性,以及它们对任何使它们偏离平衡的东西作出反应的内在倾向。在这种情况下,扭曲的媒介是坍缩的主空间不断增加的曲率。

英文摘要:

Electromagnetism appears to have the potential to alter the fate of relativistic gravitational implosion. Coulomb forces, for example, can in principle prevent the ultimate collapse of charged matter to a singularity. Also, half a century ago, Mael Melvin noted that magnetic forcelines do not collapse under their own gravity, no matter how strong the latter may be. Instead, magnetic fields seemed capable of stabilising themselves against gravitational self-contraction. Intrigued, Melvin wondered whether magnetism could also support against the realistic collapse of charged matter. Here, we look back into these issues by means of two complementary scenarios. The first reconsiders Melvin's highly idealised "magnetic universe" and reaches the same conclusion, namely that magnetic fields do not self-gravitate. The second is a realistic collapse scenario, like that of magnetised massive compact stars. Looking for answers to Melvin's question, we find that magnetic fields do show a generic tendency to support against relativistic gravitational implosion. The magnetic effect in question involves the curvature of the host space, it grows stronger as the collapse progresses and the triggering agent is the field's tension. In other words, the reason is the elasticity of the field lines and their inherent tendency to react against anything that distorts them from equilibrium. In this case, the distorting agent is the ever increasing curvature of the collapsing host space.

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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