Editing Van Allen radiation belt (section)

==Causes==
It is generally understood that the inner and outer Van Allen belts result from different processes. The inner belt is mainly composed of energetic protons produced from the decay of [[neutrons]], which are themselves the result of [[cosmic ray]] collisions in the upper atmosphere. The outer Van Allen belt consists mainly of electrons. They are injected from the geomagnetic tail following geomagnetic storms, and are subsequently energized through [[Two stream instability#Wave-particle interactions|wave-particle interactions]].

In the inner belt, particles that originate from the Sun are trapped in the Earth's magnetic field. Particles spiral along the magnetic lines of flux as they move "latitudinally" along those lines. As particles move toward the poles, the magnetic field line density increases, and their "latitudinal" velocity is slowed and can be reversed, deflecting the particles back towards the equatorial region, causing them to bounce back and forth between the Earth's poles.<ref>{{cite web |last1=Stern |first1=David P. |last2=Peredo |first2=Mauricio |title=The Exploration of the Earth's Magnetosphere |website=The Exploration of the Earth's Magnetosphere |publisher=[[NASA]] / [[Goddard Space Flight Center]] |url=http://www-spof.gsfc.nasa.gov/Education/Intro.html |access-date=2013-09-27 |archive-date=2013-08-15 |archive-url=https://web.archive.org/web/20130815210747/http://www-spof.gsfc.nasa.gov/Education/Intro.html |url-status=dead }}</ref> In addition to both spiralling around and moving along the flux lines, the electrons drift slowly in an eastward direction, while the protons drift westward.

The gap between the inner and outer Van Allen belts is sometimes called the "safe zone" or "safe slot", and is the location of [[medium Earth orbit]]s. The gap is caused by the [[Very low frequency|VLF radio waves]], which scatter particles in [[pitch angle (particle motion)|pitch angle]], which adds new ions to the atmosphere. Solar outbursts can also dump particles into the gap, but those drain out in a matter of days. The VLF radio waves were previously thought to be generated by turbulence in the radiation belts, but recent work by [[James L. Green|J.L. Green]] of the [[Goddard Space Flight Center]]{{citation needed|date=February 2023}} compared maps of lightning activity collected by the [[Microlab 1]] spacecraft with data on radio waves in the radiation-belt gap from the [[IMAGE (spacecraft)|IMAGE]] spacecraft; the results suggest that the radio waves are actually generated by lightning within Earth's atmosphere. The generated radio waves strike the ionosphere at the correct angle to pass through only at high latitudes, where the lower ends of the gap approach the upper atmosphere. These results are still being debated in the scientific community.