There are four currently competing models of mechanisms that lead to an SSD-ADAF transition, i.e., strong ADAF principle, evaporation, Honma mechanism and thermal instability in the inner SSD zone.

• 关于SSD-ADAF的转变机制目前有强ADAF原则、蒸发机制、Honma机制和SSD内区的热不稳定引发机制。