A point charge represented by the small aluminum sphere is attracted to a large sphere. The large sphere is charged, insulated, and conducting. The point charge and the large sphere carry electric charges equal in magnitude but opposite in sign. The electric field lines (in green) are computed using the potential given by Jackson equation (2.8), Section 2.3. The large sphere is taken to be infinitely massive, and the equation of motion of the point charge is computed using Jackson's equation (2.9) for the force between the two. The point charge is initially moving radially away from the large sphere at 1.5 radii (of the large sphere), but does not have enough energy to escape, and is pulled back. The animation ends when the small sphere returns to 1.5 radii.

Again this is an example of the tension exerted parallel to the field. The tension in the field pulls on both charges, trying to get them together.