An Interesting Force.

A plot of the force between electrons in parallel orbits given by,

$F_a=-\cfrac { n_{ e }q^{ 2 } }{ 4\varepsilon _{ o } } \cfrac { r-r_e }{ \left\{ (2a_{ e })^{ 2 }+(r-r_e)^{ 2 } \right\} ^{ 3/2 } } d\,r$

is provided below.

It is both repulsive (positive) and attractive (negative) depending on the value of $r_e$.  A most interesting force.