Accretion Disk Instabilities

摘要: Basic properties of accretion disk instabilities are summarized. We first explain the standard model by Shakura and Sunyaev. In this model, dominant sources viscosity assumed to be chaotic magnetic fields turbulence in gas flow, magnitude is prescribed so-called α model. It then possible build a particular framework disks stationary, but when some basic assumptions relaxed, various kinds appear. particular, we focus on thermal limit-cycle instability caused partial ionization hydrogen (and helium). demonstrate that well accounts for observed features outbursts dwarf novae X-ray nova. introduce other based They suspected produce time variabilities wide range timescales close binaries active galactic nuclei.