Theory and computer simulations are used to describe the inelastic vortex–vortex and vortex–wave interactions that lead to the quasicoherent transport of plasma across a constant magnetic field in 2-D systems. Monopole and dipole drift wave vortices with radii r0 large compared with the ion inertial scale length ρs are shown to produce transport at the rate un ∫ dσ(b)≤nvvder0, where nv is the vortex line density and dσ(b) is the inelastic collision cross section for the impact parameter b. The transport during collisions and mergings is evaluated from the evolution of a passively convected scalar concentration of test particles.