Flow channeling in magnetohydrodynamic jets and mixing layers

Incompressible hydrodynamic (HD) jets and mixing layers satisfy Rayleigh criterion, and hence are naturally susceptible to Kelvin-Helmholtz (KH) instability. However, for magnetohydrodynamic (MHD) jets and mixing layers at high magnetic field strengths we show by means of linear analysis and numerical simulations that the interaction of shear with Alfv\'en waves ceases KH instability to exist. Linear analysis shows that the behavior of velocity perturbation along the direction of shear is crucial in the evolution of KH instability. We prove that the evolution of this velocity perturbation becomes oscillatory at high magnetic field strengths. This oscillatory behavior results in the confinement of the fluid particle displacement to a narrow region in the flow. We label this phenomenon "flow channeling" to indicate the confinement of the fluid particles without needing any physical boundaries.