Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Shearing Box Simulations of the MRI in a Collisionless Plasma   We describe local shearing box simulations of turbulence driven by the
magnetorotational instability (MRI) in a collisionless plasma. Collisionless
effects may be important in radiatively inefficient accretion flows, such as
near the black hole in the Galactic Center. The MHD version of ZEUS is modified
to evolve an anisotropic pressure tensor. A fluid closure approximation is used
to calculate heat conduction along magnetic field lines. The anisotropic
pressure tensor provides a qualitatively new mechanism for transporting angular
momentum in accretion flows (in addition to the Maxwell and Reynolds stresses).
We estimate limits on the pressure anisotropy due to pitch angle scattering by
kinetic instabilities. Such instabilities provide an effective ``collision''
rate in a collisionless plasma and lead to more MHD-like dynamics. We find that
the MRI leads to efficient growth of the magnetic field in a collisionless
plasma, with saturation amplitudes comparable to those in MHD. In the saturated
state, the anisotropic stress is comparable to the Maxwell stress, implying
that the rate of angular momentum transport may be moderately enhanced in a
collisionless plasma.

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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
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The categories of this paper are: math-ph
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The categories of this paper are: stat
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: econ
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The categories of this paper are: hep-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: supr-con
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The categories of this paper are: mtrl-th