Structure and Stability of Advection-Dominated Accretion Disks

平流主导吸积盘的结构和稳定性

• 批准号: 08640328
• 负责人: KATO Shoji
• 金额: $ 1.6万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08640328/
• 关键词: Accrefion Disks; Advection-Dominated Accretion Disks; Two-Temperature Disks; Thermal Instabilcty; Turbulence; 安定性; 二温度系

1)Construction of Advection-Dominated Accretion DisksAfter having constructed one-temperature advection-dominated disk models in collaboration with Prof. E.Narayan, we proceeded to make two-temperature advectiondominated disk models. First we made such disk models, taking only bremsstrahlung as cooling processes of electron gas. After this success, we constructed more general models, taking Compton and synchrotron processes into account as cooling processes of electron gas.2)Thermal Instability of Advection-Dominated Accretion DisksExamination of thermal instability of advection-dominated disks is of importance in relation to understanding origins of time variations of X-ray stars and active galactic nulei. Since advection-dominated disks are relatively thick in the vertical direction, their thermal instability should be studied by a method different from that used for standard disks. Our analyzes show that advection-dominated accretion disks are weakly unstable against local perturbations, if turbulent heat conduction is negligible.3)Turbulence in non-magnetized Keplerian disksKeplerian disks are highly stable against axially symmetric perturbations (Rayleigh criterion). In this sense, it is usually supposed that magnetic field will be necessary to make the disks turbulent (Balbus-Hawley instability). We think this argument is not always correct, and constructed a possible model of hydrodynamic turbulence in Keplerian disks.

1)在与E.Narayan教授合作建立了一个温度平流主导的圆盘模型之后，我们继续建立两个温度平流主导的圆盘模型。首先，我们建立了这样的圆盘模型，只考虑电子气的韧致辐射冷却过程。在此成功之后，我们建立了更一般的模型，考虑康普顿和同步加速器过程作为电子气体的冷却过程。2）平流主导吸积盘的热不稳定性研究平流主导吸积盘的热不稳定性对于理解X射线星和活动星系核的时间变化的起源具有重要意义。由于平流主导的圆盘在垂直方向上相对较厚，因此应采用与标准圆盘不同的方法来研究其热不稳定性。结果表明，在湍流热传导可以忽略的情况下，对流占优吸积盘对局部扰动是弱不稳定的。3）非磁化开普勒盘中的湍流开普勒盘对轴对称扰动（Rayleigh判据）是高度稳定的。从这个意义上说，通常认为磁场是使盘产生湍流（Balbus-Hawley不稳定性）所必需的。我们认为这一论点并不总是正确的，并建立了一个可能的模型的流体动力学湍流开普勒磁盘。

项目成果

K.E.Nakamura, M.Kusunose, R.Matsumoto, and S.Kato: "Two-Temperature Transonic Accretion Disks" IAU Symp.eds.K.Koyama et al.No.188, in press. (1998)

K.E.Nakamura、M.Kusunose、R.Matsumoto 和 S.Kato：“双温度跨音速吸积盘”IAU Symp.eds.K.Koyama 等人第 188 号，正在出版。

S.Kato: "Thermal Inslability of Advection-Dominated Disks against Local Perturbation Revised" Publ Astron Soc.Japan. 49. 221-225 (1997)

S.Kato：“平流主导盘对局部扰动的热不稳定性修订”Publ Astron Soc.Japan。

S.Kato: "Steady Hydrodynamic Turbulence in Differentially Rotating Disks" Publ.Aslron.Soc.Japan. 49. 213-220 (1997)

S.Kato：“差动旋转盘中的稳定流体动力学湍流”Publ.Aslron.Soc.Japan。

S.Kato: "Thermal Instability of Achvection-Dominated Disks aganst Local Perturbatrons Revised." Puld.Astron.Soc.Japan. 49. 221-225 (1997)

S.Kato：“对运动主导盘相对局部扰动的热不稳定性进行了修订。”

S.Kato, M.A., Abramowicz, and X.Chen: "Thermal Instability of Advection-Dominated Disks against Local Perturbations" Publ.Astron.Soc.Japan. 48. 67-75 (1996)

S.Kato、M.A.、Abramowicz 和 X.Chen：“平流主导盘对局部扰动的热不稳定性”Publ.Astron.Soc.Japan。