The structure of the quiet-time magnetotail is studied using a test particle simulation. Vlasov equilibria are obtained in the regime vD=Eyc/Bz is much less than the ion thermal velocity and are self-consistent in that the current and magnetic field satisfy Ampere's law. Force balance between the plasma and magnetic field is satisfied everywhere. The global structure of the current sheet is found to be critically dependent on the source distribution function. The pressure tensor is nondiagonal in the current sheet with anisotropic temperature. A kinetic mechanism is proposed whereby changes in the source distribution results in a thinning of the current sheet. ¿ American Geophysical Union 1993