The nonlinear evolution of magnetic islands is investigated by means of numerical simulations. The growth and saturation of the island are shown to depend not only on asymptotic tearing mode stability parameter Δ ′ but also on the initial global current profile. Presence of the external current sheets leads to the formation of different island state for the same value of Δ ′. It is found that the flow vorticity generated by the interacting current sheets is an important feature of nonlocal interactions and nonlocal effects in magnetic islands dynamics.
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