PMO OpenIR  > 太阳高能及相关物理过程研究团组
Black Hole Accretion in Low States Electron Heating
Siming Liu ; Christopher L ; Fryer† ; Hui Li
Source PublicationThe Open Astronomy Journal
AbstractPlasmas in an accretion flow are heated by magneto-hydrodynamic turbulence generated through the magnetorotationalinstability (MRI). The viscous stress driving the accretion is intimately connected to the microscopic processesof turbulence dissipation. We show that, in a few well-observed black hole accretion systems, there is compellingobservational evidence of efficient electron heating by turbulence or collective plasma effects in low accretion states,when Coulomb collisions are not efficient enough to establish a thermal equilibrium between electrons and ions at smallradii. We consider a Keplerian two-temperature accretion flow with a constant mass accretion rate in the pseudo-Newtonian gravitational potential and take into account the bremsstrahlung, synchrotron, and inverse Comptonizationcooling processes. The balance of gravitational energy dissipation and turbulence energy cascade requires that the viscousstress be proportional to the product of the turbulence kinetic energy density and the total turbulence energy density,which may contradict the result of some shearing box simulations that the viscous stress is proportional to the magneticfield energy density. The critical mass accretion rate, below which the two-temperature solution may exist, is determinedby the cooling processes and the collisional energy exchanges between electrons and ions and has very weak dependenceon the collision-less heating of electrons by turbulence, which becomes more important at lower accretion rates. If thecollision-less heating is dominated by the transit-time damping processes, small scale waves propagating obliquely withrespect to the large scale magnetic field are prohibited, which may affect the saturate state of the MRI driven urbulencesignificantly. The plasma also needs to be strongly magnetized with the magnetic field and proton energy densitiescomparable so that electrons can share more of the dissipated gravitational energy. The heating of relativistic electrons isefficient since the heating rate is proportional to the mean momentum of the particles, and
KeywordAcceleration Of Particles Accretion Accretion Disks Black Hole Physics Plasmas Radiation Mechanisms Thermal Turbulence
Subject AreaAstronomy & Astrophysics
Document Type期刊论文
Recommended Citation
GB/T 7714
Siming Liu,Christopher L,Fryer†,et al. Black Hole Accretion in Low States Electron Heating[J]. The Open Astronomy Journal,2011(4):38-53.
APA Siming Liu,Christopher L,Fryer†,&Hui Li.(2011).Black Hole Accretion in Low States Electron Heating.The Open Astronomy Journal(4),38-53.
MLA Siming Liu,et al."Black Hole Accretion in Low States Electron Heating".The Open Astronomy Journal .4(2011):38-53.
Files in This Item:
File Name/Size DocType Version Access License
2011145Black Hole Ac(1118KB) 开放获取LicenseView Application Full Text
Related Services
Recommend this item
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[Siming Liu]'s Articles
[Christopher L]'s Articles
[Fryer†]'s Articles
Baidu academic
Similar articles in Baidu academic
[Siming Liu]'s Articles
[Christopher L]'s Articles
[Fryer†]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[Siming Liu]'s Articles
[Christopher L]'s Articles
[Fryer†]'s Articles
Terms of Use
No data!
Social Bookmark/Share
File name: 2011145Black Hole Accretion in Low States Electron Heating.pdf
Format: Adobe PDF
All comments (0)
No comment.

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.