LAUSR

Abstract In electrodeposition under a uniform parallel magnetic field, the suppression of three-dimensional (3D) nucleation by microscopic magnetohydrodynamic flow (micro-MHD flow) and formation of stream pattern of macroscopic MHD flow by the multiple nucleation of 3D nuclei are theoretically clarified. The interference of micro-MHD flow with concentration fluctuation generally results in the suppression of 3D nucleation (1st micro-MHD effect). However, due to the small scale of length of 3D nucleus, the effective viscosity is too high for micro-MHD flow to sufficiently work on individual 3D nuclei, so that the suppression is not so obvious. On the other hand, for 3D nucleus groups after multiple nucleation, due to larger scale of length, effective viscosity decreases, so that micro-MHD flow easily interacts with the corresponding concentration fluctuation, which gives rise to a striped pattern reflecting macroscopic MHD flow.