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| Paper: |
A Magnetohydrodynamical Model for the Formation of Episodic Jets |
| Volume: |
427, Accretion and Ejection in AGN: a Global View |
| Page: |
135 |
| Authors: |
Yuan, F.; Lin, J.; Wu, K.; Ho, L. C. |
| Abstract: |
Episodic ejection of plasma blobs have been observed in many black
hole systems. While steady, continuous jets are believed to be
associated with large-scale open magnetic fields, what causes the
episodic ejection of blobs remains unclear. By analogy with the
coronal mass ejection on the Sun, we propose a magnetohydrodynamical
model for episodic ejections from black holes associated with the
closed magnetic fields in an accretion flow. Shear and turbulence of
the accretion flow deform the field and result in the formation of a
flux rope in the disk corona. Energy and helicity are accumulated
and stored until a threshold is reached. The system then loses its
equilibrium and the flux rope is thrust outward by the magnetic
compression force in a catastrophic way. Our calculations show that
for parameters appropriate for the black hole in our Galactic
center, the plasmoid can attain relativistic speeds in about 35
minutes. |
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