On the dynamo driven accretion disks

	On the dynamo driven accretion disks
	Ma, CY ; Biermann, PL
刊名	ASTRONOMY & ASTROPHYSICS
	1998-06-10
卷号	334 期号:2 页码:736-741
关键词	magnetic fields MHD instabilities accretion, accretion disks turbulence
ISSN号	0004-6361
英文摘要	We add the alpha- effect in the dynamo driven accretion disk model proposed by Tout & Pringle (1992), i.e., a dynamo model depends on the physical processes such as Parker instability, B-H instability, magnetic field reconnection and alpha-omega mean field dynamo as well. The alpha- effect in the dynamo mechanism is determined by the strength of turbulence of the accretion flow. When the turbulent Mach number M-t is less than 0.25, the solutions of the magnetic fields oscillate around their equilibrium values. Increasing the value of M-t makes the amplitude of the oscillation smaller and the period longer, but does not affect the equilibrium values. The Shakura-Sunyaev viscosity parameter alpha(SS) oscillates around the equilibrium value of 0.33. When the turbulent Mach number M-t is larger than 0.25, the magnetic field components reach a stable state. In the non-linear dynamo region, the critical turbulent Mach number M-t is 0.44 rather than 0.25. The oscillating magnetic fields and viscosity parameter can explain the basic properties of the dwarf nova eruptions and some properties of quiescent disks (Armitage al. 1996).
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	ACTIVE GALACTIC NUCLEI ; SCALE MAGNETIC-FIELDS ; BLACK-HOLES ; SIMPLE-MODEL ; TURBULENCE ; INSTABILITY ; STABILITY ; SYSTEMS
收录类别	SCI
语种	英语
WOS记录号	WOS:000074460500045
公开日期	2013-02-05
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/8368]
专题	紫金山天文台_期刊（老文献）
作者单位	1.Max Planck Inst Radioastron, D-53121 Bonn, Germany 2.Acad Sinica, Purple Mt Observ, Nanjing 210008, Peoples R China
推荐引用方式 GB/T 7714	Ma, CY,Biermann, PL. On the dynamo driven accretion disks[J]. ASTRONOMY & ASTROPHYSICS,1998,334(2):736-741.
APA	Ma, CY,&Biermann, PL.(1998).On the dynamo driven accretion disks.ASTRONOMY & ASTROPHYSICS,334(2),736-741.
MLA	Ma, CY,et al."On the dynamo driven accretion disks".ASTRONOMY & ASTROPHYSICS 334.2(1998):736-741.