Development of the electromagnetic field in the magnetosphere-ionosphere system is examined under the condition that a constant current generator supplied current to the system after t=0. It is shown that at high altitudes there are intervals when the electric field is transiently directed opposite to the direction of the supplied current. Namely, transient dusk-to-dawn electric field can be generated from ionospheric channeling of the dawn-to-dusk tail current during an early stage of the development of the tail-ionosphere current system. Electric field with the opposite polarity is produced during intervals when the field reflected from the ionosphere dominates over the incident field.