The linear and nonlinear stability of a heterogeneous incompressible inviscid perfectly conducting fluid between two cylinders is investigated in the presence of a radial gravitational force and geostrophic force. The stability for linear disturbances is investigated using the normal mode method, while the nonlinear stability is investigated by applying the energy method. In the case of linear theory, it is found that a necessary condition for in stability is that the algebraic sum of hydrodynamic, hydromagnetic and rotation Richardson number is less than one quarter somewhere in the fluid. A semi-circle theorem similar to that of Howard is also obtained.