I've seen inner and outer Van Allen belt drawings that have the inner belt consisting of protons and the outer belt consisting of electrons. I am guessing this is due to differences in the mass density or the charge density differences of the two. So we have charge separation in the Van Allen belt, a potential difference, and a build up of this charge is all we need to reach the critical voltage to cause a current to flow. What would it take for the Van Allen radiation belt to discharge: solar storm, cosmic dust, distant gamma ray bursts? Anyone have data on the volume, charge density and other physical properties of the Van Allen belt? Because I was wondering if a possible bolide impact or volcanic eruption could cause a discharge. These would have to be significantly large events so I am trying to find out just how big they would have to be.