Phase Slip Solutions in Magnetically Modulated Taylor-Couette Flow

We numerically investigate Taylor-Couette flow in a wide-gap configuration, with ri/ro = 1/2, the inner cylinder rotating, and the outer cylinder stationary. The fluid is taken to be electricallyconducting, and a magnetic field of the form Bz ≈ (1 + cos(2πz/z0))/2 is externally imposed, where the wavelength z0 = 50(ro−ri). Taylor vortices form where the field is weak, but not where it is strong. As the Reynolds number measuring the rotation rate is increased, the initial onset of vortices involves phase slip events, whereby pairs of Taylor vortices are periodically formed and then drift outward, away from the midplane where Bz = 0. Subsequent bifurcations lead to a variety of other solutions, including ones both symmetric and asymmetric about the midplane. For even larger Reynolds numbers a different type of phase slip arises, in which vortices form at the outer edges of the pattern and drift inward, disappearing abruptly at a certain point. These solutions can also be symmetric or asymmetric about the midplane, and co-exist at the same Reynolds number. Many of the dynamics of these phase slip solutions are qualitatively similar to previous results in geometrically ramped Taylor-Couette flows.