Time averaged, means the positive particle are not on the transverse plane perpendicular to the orbit at the same time, but over a period of their spins, they are once there.
Obviously, the attraction on the negative charge, \(E\) per unit charge, is less when the orbit separation, \(d\) is large.
And when the fence is low, the lamb jumps over...albeit only a part-time escape artiste.
Saving data quota mode...