Omega effect (${\partial }_t{B}_{\mathrm{tor}}\sim \Omega B_{\mathrm{pol}}$)

Differential rotation or shear stretches a poloidal magnetic field into a toroidal magnetic field. This is the Omega effect. By itself it need not regenerate the poloidal component; the alpha effect provides one possible feedback mechanism in an alpha-Omega dynamo. Without feedback, shear amplification can be transient or algebraic rather than sustained exponential dynamo action.