Bimodal accretion disks: Shakura-Sunyaev disk-advection-dominated accretion flow transitions

We show that, unlike the results presented previously in the literature, th e transition from an outer Shakura-Sunyaev disk (SSD) to an advection-domin ated accretion flow (ADAF) is possible for large values of the viscosity pa rameter alpha > 0.5. The transition is triggered by the thermal instability of a radiation pressure-supported SSD. The transition radius is close to t he central black hole. We confirm our qualitative prediction by actually co nstructing global bimodal SSD-ADAF solutions.