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arXiv 1702.07322astro-ph.HE
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无力磁层极限下内Alfvén面位置对黑洞能量提取的影响

Effects of Inner Alfvén Surface Location on Black Hole Energy Extraction in the Limit of a Force-Free Magnetosphere

Kevin Thoelecke, Masaaki Takahashi, Sachiko Tsuruta

摘要:

一个能量提取的黑洞磁层可以通过其内部阿尔文表面的位置来定义,阿尔文表面决定了黑洞沿着给定磁场线提取能量的速率。我们研究了在无力极限下,内Alfvén面的位置如何改变能量提取黑洞磁层的结构。通过广义相对论扩展的牛顿磁摩擦方法,数值计算了数百个磁层的全范围的黑洞自旋和流动参数。我们发现,喷流状结构自然形成非常接近视界附近的阿尔文表面的边界的能层和能量被提取朝向赤道平面的阿尔文表面接近视界。这表明,可能存在两大类提取能量的黑洞磁层;那些将提取的能量直接传输给远处的观察者,以及那些将提取的能量传输给附近的吸积物质。应用于瞬态高能量现象,我们发现,它们也可能在时间尺度上不同的一个因素,20或更多。

英文摘要:

An energy extracting black hole magnetosphere can be defined by the location of its inner Alfvén surface, which determines the rate of black hole energy extraction along a given magnetic field line. We study how the location of the inner Alfvén surface can modify the structure of energy extracting black hole magnetospheres in the force-free limit. Hundreds of magnetospheres are numerically computed via a general relativistic extension of the Newtonian magnetofrictional method for a full range of black hole spins and flow parameters. We find that jet-like structures naturally form very close to the horizon for Alfvén surfaces near the boundary of the ergosphere and that energy is extracted towards the equatorial plane for Alfvén surfaces close to the horizon. This suggests that two broad classes of energy extracting black hole magnetospheres might exist; those that transmit extracted energy directly to distant observers, and those that transmit extracted energy to nearby accreting matter. Applied to transient high energy phenomena, we find that they might also differ in timescale by a factor of 20 or more.

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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