磁化黑洞吸积盘的演化及放能效率  

Evolution and Efficiency of Releasing Energy of a Magnetized Black-Hole Accretion Disk

作　　者：肖看[1] 汪定雄[1] 雷卫华[1] 

机构地区：[1]华中科技大学物理系,武汉430074

出　　处：《天文学报》2002年第2期178-188,共11页Acta Astronomica Sinica

基　　金：国家自然科学基金资助(No.10173004)

摘　　要：采用等效电路模型讨论了两种不同类型的磁场对黑洞的旋转能量和角动量的提取机制: Blandford—Znajek(BZ)过程和磁耦合过程.在研究磁化吸积盘中心黑洞自转参量演化特征的基础上,详细比较了纯吸积过程、BZ过程和磁耦合过程对黑洞吸积盘放能效率的贡献.结果表明,磁耦合过程是提取黑洞旋转能量重要的新机制,其放能效率与BZ过程几乎相等.在黑洞自转不足特别大的情况,纯吸积过程的放能效率高于BZ过程和磁耦台过程的放能效率,但足当黑洞自转接近极端Kerr黑洞的自转状态时,放能效率主要由BZ过程和磁耦合过程贡献.Two types of mechanisms of extracting energy and angular momentum from a rotating black hole by magnetic field, the Blandford-Znajek(BZ) process and magnetic coupling process, are investigated based on an improved equivalent circuit model. The contribution to the efficiencies of releasing energy from pure accretion process, the BZ process and magnetic coupling process are compared in detail by studying the evolution characters of the spin parameters of the black hole at the center of the magnetized accretion disk. It is shown that magnetic coupling process is an important new mechanism of extracting energy from rotating black holes, the efficiency of releasing energy of which is almost the same as that of the BZ process. The efficiency of releasing energy from pure accretion process is dominated over those of the BZ process and magneticc coupling pocess, while the latter two efficiencies are dominated over the former as the black hole spin approaches unity.

关 键 词：磁化黑洞吸积盘 放能效率 等效电路模型 黑洞物理 磁场 吸积盘 星系 

分 类 号：P145.8[天文地球—天体物理]