Analysis of the magneto-rotational instability with the effect of cosmic-ray diffusion

Abstract

We present the results obtained from linear stability analysis and 2.5-dimensional magnetohydrodynamic (MHD) simulations of the magnetorotational instability (MRI), including the effects of cosmic rays (CRs). We took into account of the CR diffusion along the magnetic field but neglect the cross-field-line diffusion. Two models are considered in this paper: shearing box model and differentially rotating cylinder model. We studied how MRI is affected by the initial CR pressure (i.e., energy) distribution. In the shearing box model, the initial state is uniform distribution. Linear analysis shows that the growth rate of MRI does not depend on the value of CR diffusion coefficient. In the differentially rotating cylinder model, the initial state is a constant angular momentum polytropic disk threaded by weak uniform vertical magnetic field. Linear analysis shows that the growth rate of MRI becomes larger if the CR diffusion coefficient is larger. Both results are confirmed by MHD simulations. The MHD simulation results show that the outward movement of matter by the growth of MRI is not impeded by the CR pressure gradient, and the centrifugal force which acts to the concentrated matter becomes larger. Consequently, the growth rate of MRI is increased. On the other hand, if the initial CR pressure is uniform, then the growth rate of the MRI barely depends on the value of the CR diffusion coefficient.

arXiv comment41 pages, 12 figures, published in ApJ in 2015

References in corpus (9)

• X-Ray Flares and Mass Outflows Driven by Magnetic Interaction between a Protostar and its Surrounding Disk
• Amplification of Galactic Magnetic Fields by the Cosmic-Ray Driven Dynamo
• Cosmic ray driven dynamo in galactic disks. A parameter study
• The Effect of Cosmic Ray Diffusion on the Parker Instability
• Nonlinear Parker Instability with the Effect of Cosmic-Ray Diffusion
• Parker-Jeans Instability of Gaseous Disks Including the Effect of Cosmic Rays
• The Acceleration Mechanism of Resistive MHD Jets Launched from Accretion Disks
• Linear Growth of the Kelvin-Helmholtz Instability with an Adiabatic Cosmic-ray Gas
• The influence of cosmic-rays on the magnetorotational instability

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