Effects of Inner Alfv��n Surface Location on Black Hole Energy Extraction in the Limit of a Force-Free Magnetosphere
| Autor: | Kevin Thoelecke, Masaaki Takahashi, Sachiko Tsuruta |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Physics
High Energy Astrophysical Phenomena (astro-ph.HE) Range (particle radiation) Spins 010308 nuclear & particles physics Plane (geometry) Astrophysics::High Energy Astrophysical Phenomena Magnetosphere FOS: Physical sciences Astrophysics 01 natural sciences Ergosphere Computational physics Magnetic field Black hole General Relativity and Quantum Cosmology 0103 physical sciences Extremal black hole Physics::Space Physics 010306 general physics Astrophysics - High Energy Astrophysical Phenomena |
| DOI: | 10.48550/arxiv.1702.07322 |
| Popis: | An energy extracting black hole magnetosphere can be defined by the location of its inner Alfv\'{e}n surface, which determines the rate of black hole energy extraction along a given magnetic field line. We study how the location of the inner Alfv\'{e}n 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 Alfv\'{e}n surfaces near the boundary of the ergosphere and that energy is extracted towards the equatorial plane for Alfv\'{e}n 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. Comment: 23 Pages, 9 Figures |
| Databáze: | OpenAIRE |
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