Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetically Driven Accretion Flows in the Kerr Metric IV: Dynamical
  Properties of the Inner Disk   This paper continues the analysis of a set of general relativistic 3D MHD
simulations of accreting tori in the Kerr metric with different black hole
spins. We focus on bound matter inside the initial pressure maximum, where the
time-averaged motion of gas is inward and an accretion disk forms. We use the
flows of mass, angular momentum, and energy in order to understand dynamics in
this region. The sharp reduction in accretion rate with increasing black hole
spin reported in Paper I of this series is explained by a strongly
spin-dependent outward flux of angular momentum conveyed electromagnetically;
when a/M > 0.9, this flux can be comparable to the inward angular momentum flux
carried by the matter. In all cases, there is outward electromagnetic angular
momentum flux throughout the flow; in other words, contrary to the assertions
of traditional accretion disk theory, there is in general no "stress edge", no
surface within which the stress is zero. The retardation of accretion in the
inner disk by electromagnetic torques also alters the radial distribution of
surface density, an effect that may have consequences for observable properties
such as Compton reflection. The net accreted angular momentum is sufficiently
depressed by electromagnetic effects that in the most rapidly-spinning black
holes mass growth can lead to spindown. Spinning black holes also lose energy
by Poynting flux; this rate is also a strongly increasing function of black
hole spin, rising to 10% or more of the rest-mass accretion rate at very high
spin. As the black hole spins faster, the path of the Poynting flux changes
from being predominantly within the accretion disk to predominantly within the
funnel outflow.

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The categories of this paper are: q-fin
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
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The categories of this paper are: nlin
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The categories of this paper are: q-alg
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th