Is it probable for an electron to be moving northward in a northward-directed electric field?

Answer:

The force exerted on a negatively charged particle with an electric field is in the direction opposite to the direction of the electric field at the location of its negatively-charged "victim". Therefore in this case there is a southward force on the electron. These consequences in a southward acceleration. If the particle is going northward as well as the electric force is the only force acting on it then the particle must be slowing down. However there is no reason that it can't be moving forward under these circumstances. It does not need a force in the northward direction to be moving northward. It's analogous to a rock thrown upward. Subsequent to it leaves the thrower's hand the rock is going upward even though the only force (assuming air resistance to be negligible) acting on it is the gravitational force which is in the downward direction. There may perhaps have been northward force acting on the particle in the past but that is part of its history. The question is regarding the electrons "here and now".