A Coulomb collision is a collision between two particles when the force between them is given by Coulomb's Law. As with any inverse-square law, the result is a hyperbolic Keplerian orbit. The distinction to gravitational interactions is important, however, when the cumulative effect of many collisions is considered. Due to Debye shielding, there is an upper limit to the distance at which the particles interact. The analysis here yields the scalings and orders of magnitude. For formulas derived from careful calculations, see page 31 ff. in the NRL Plasma formulary.