The early time dynamics of an AMPTE release in the solar wind is studied using a three-dimensional particle simulation. The results of the simulation explain the dynamics of the solar wind ions, release ions, and the current system that the release sets up. It is found that, within the limits of charge quasi-neutrality and the recognition of differential reference frames caused by the inertia of the release ions, the cross-field motion of the ions can be understood. It is also found in these simulations that the convection of the magnetic field around the release is asymmetric and that the solar wind ion interaction is also asymmetric. From this feature and the correlation between the three-dimensional and two-dimensional simulations it is seen that the AMPTE releases produce physics that is somewhat different from that of a planet or a comet. ¿American Geophysical Union 1987