Black hole in a uniform magnetic field
Black hole in a uniform magnetic field
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DOI：
10.1103/physrevd.10.1680
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发表时间：
1974-09
影响因子：
5
通讯作者：
R. Wald
中科院分区：
文献类型：
--
作者：
R. Wald
利用真空时空中的Killing矢量作为麦克斯韦测试场的矢量势这一事实，我们导出了当一个静止的轴对称黑洞被放置在一个沿黑洞对称轴沿着排列的均匀磁场中时所产生的电磁场的解。证明了磁场中的黑洞会选择性地吸积电荷，直到其电荷变为$Q=2{B}_{0}J$，其中${B}_{0}$为磁场强度，$J$为黑洞的角动量.作为这里给出的分析的一个副产品，我们证明了一个轻微带电的，静止的，轴对称的黑洞（不假设是克尔）的旋磁比必须有值$g=2$。
Using the fact that a Killing vector in a vacuum spacetime serves as a vector potential for a Maxwell test field, we derive the solution for the electromagnetic field occurring when a stationary, axisymmetric black hole is placed in an originally uniform magnetic field aligned along the symmetry axis of the black hole. It is shown that a black hole in a magnetic field will selectively accrete charges until its charge becomes $Q=2{\mathrm{Bb}}_{0}J$, where ${B}_{0}$ is the strength of the magnetic field and $J$ is the angular momentum of the black hole. As a by-product of the analysis given here, we prove that the gyromagnetic ratio of a slightly charged, stationary, axisymmetric black hole (not assumed to be Kerr) must have the value $g=2$.