model of weakly magnetized, isothermal accretion disks with viscosity is investigated in this paper.The influences of the diffusion-type viscosity, vertical magnetic field and azimuthal magnetic field on the axisymmetric pulsational instability in this model are discussed.It is shown that there exist four modes of axisymmetric oscillations in the disks, arising from the axisymmetric perturbations.Two of these modes are always pulsationally unstable, and the viscosity and the magnetic fields act as factors of instability.The other two modes are always stable, and the viscosity and the magnetic ...
