Analysis of magnetorotational instability with the effect of cosmic-ray diffusion

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/101360

Title:	Analysis of magnetorotational instability with the effect of cosmic-ray diffusion
Authors:	高仲明;Kuwabara, Takuhito;Ko, Chung-Ming
Contributors:	理學院天文研究所
Keywords:	ACCRETION DISKS;ANGULAR MOMENTUM;ASTROPHYSICS, COSMOLOGY AND ASTRONOMY;BOX MODELS;Computer simulation;COMPUTERIZED SIMULATION;COSMIC RADIATION;DIFFUSION;Diffusion coefficient;ENERGY SPECTRA;GALAXIES;Instability;Linear analysis;MAGNETIC FIELDS;MAGNETOHYDRODYNAMICS;MHD;PRESSURE GRADIENTS;SHEAR
Date:	2015-01-10
Issue Date:	2026-04-21 14:31:27 (UTC+8)
Publisher:	IOP Publishing Ltd.;United States
Abstract:	摘要： We present the results obtained from the linear stability analysis and 2.5 dimensional magnetohydrodynamic (MHD) simulations of magnetorotational instability (MRI), including the effects of cosmic rays (CRs). We took into account the CR diffusion along the magnetic field but neglected the cross-field-line diffusion. Two models are considered in this paper: the 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 the CR diffusion coefficient. In the differentially rotating cylinder model, the initial state is a constant angular momentum polytropic disk threaded by a 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 that acts on 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. 出版者： United States 出版日期： 2015-01-10 出處： The Astrophysical journal, 2015-01, Vol.798 (2), p.79-12 資源來源： Institute of Physics Journals 識別號： ISSN: 1538-4357 識別號： ISSN: 0004-637X 識別號： EISSN: 1538-4357 識別號： DOI: 10.1088/0004-637X/798/2/79
Appears in Collections:	[Graduate Institute of Astronomy] journal & Dissertation

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