Magnetohydrodynamic simulations are used to predict which modes of implosion are in operation in nested wire array experiments. Separate r-theta plane simulations of the flux of plasma imploding towards the axis from the outer array and the bombardment of the inner array by this flux are presented. The different implosion modes are distinguished by the level of momentum transfer and magnetic flux compression during collision. For typical configurations, large interwire gaps (>1.5 mm) are required in the inner array in order to access the advantageous mode where the outer array material passes through. (C) 2001 American Institute of Physics.