THERMAL STABILITY OF A THIN DISK WITH MAGNETICALLY DRIVEN WINDS

	THERMAL STABILITY OF A THIN DISK WITH MAGNETICALLY DRIVEN WINDS
	Li, Shuang-Liang 1,2,3; Begelman, Mitchell C.2,3,4
刊名	ASTROPHYSICAL JOURNAL
	2014-05-01
卷号	786 期号:1 页码:6-14
关键词	accretion black hole physics magnetohydrodynamics (MHD) instabilities accretion disks
通讯作者	李双良
英文摘要	The absence of thermal instability in the high/soft state of black hole X-ray binaries, in disagreement with the standard thin disk theory, has been a long-standing riddle for theoretical astronomers. We have tried to resolve this question by studying the thermal stability of a thin disk with magnetically driven winds in the <(M) over dot>(crit)-Sigma plane. It is found that disk winds can greatly decrease the disk temperature and thus help the disk become more stable at a given accretion rate. The critical accretion rate, <(M) over dot>(crit), corresponding to the thermal instability threshold, is significantly increased in the presence of disk winds. For alpha = 0.01 and B-phi = 10B(p), the disk is quite stable even for a very weak initial poloidal magnetic field [beta(p,0) similar to 2000, beta(p) = (P-gas + P-rad)/(B-p(2)/8 pi)]. However, when beta(p) = B-p or B-phi = 0.1B(p), a somewhat stronger (but still weak) field (B-p,B-0 similar to 200 or B-p,B-0 similar to 20) is required to make the disk stable. Nevertheless, despite the great increase of <(M)over dot>(crit), the luminosity threshold, corresponding to instability, remains almost constant or decreases slowly with increasing <(M) over dot>(crit) due to decreased gas temperature. The advection and diffusion timescales of the large-scale magnetic field threading the disk are also investigated in this work. We find that the advection timescale can be smaller than the diffusion timescale in a disk with winds, because the disk winds take away most of the gravitational energy released in the disk, resulting in the decrease of the magnetic diffusivity. and the increase of the diffusion timescale.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	DOMINATED ACCRETION DISKS ; BLACK-HOLE CANDIDATE ; IGR J17091-3624 ; GALACTIC NUCLEI ; BINARY-SYSTEMS ; INSTABILITY ; FLOWS ; SIMULATIONS ; MECHANISMS ; VISCOSITY
收录类别	SCI
语种	英语
WOS记录号	WOS:000335810700006
公开日期	2015-02-14
内容类型	期刊论文
源URL	[http://119.78.226.72//handle/331011/15780]
专题	上海天文台_星系宇宙学重点实验室
作者单位	1.Chinese Acad Sci, Shanghai Astron Observ, Key Lab Res Galaxies & Cosmol, Shanghai 200030, Peoples R China 2.Univ Colorado, JILA, Boulder, CO 80309 USA 3.Natl Inst Stand & Technol, Boulder, CO 80309 USA 4.Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA
推荐引用方式 GB/T 7714	Li, Shuang-Liang,Begelman, Mitchell C.. THERMAL STABILITY OF A THIN DISK WITH MAGNETICALLY DRIVEN WINDS[J]. ASTROPHYSICAL JOURNAL,2014,786(1):6-14.
APA	Li, Shuang-Liang,&Begelman, Mitchell C..(2014).THERMAL STABILITY OF A THIN DISK WITH MAGNETICALLY DRIVEN WINDS.ASTROPHYSICAL JOURNAL,786(1),6-14.
MLA	Li, Shuang-Liang,et al."THERMAL STABILITY OF A THIN DISK WITH MAGNETICALLY DRIVEN WINDS".ASTROPHYSICAL JOURNAL 786.1(2014):6-14.