Editing Van Allen radiation belt (section)

== Inner belt ==
[[File:Rendering of Van Allen radiation belts of Earth 2.jpg|thumb|[[Cutaway drawing]] of two radiation belts around Earth: the inner belt (red) dominated by protons and the outer one (blue) by electrons. Image Credit: NASA]]
The inner Van Allen Belt extends typically from an altitude of 0.2 to 2 Earth radii ([[L-shell|L values]] of 1.2 to 3) or {{Convert|1000|km|abbr=on}} to {{Convert|12000|km|abbr=on}} above the Earth.<ref name="howstuffworks van allen belts" /><ref>{{Cite journal
| author=Ganushkina, N. Yu
| author2=Dandouras, I.
| author3=Shprits, Y. Y.
| author4=Cao, J.
| title=Locations of boundaries of outer and inner radiation belts as observed by Cluster and Double Star
| journal=[[Journal of Geophysical Research]] |volume=116 | issue=A9
| doi=10.1029/2010JA016376
| date=2011
| pages=n/a
| bibcode = 2011JGRA..116.9234G | hdl=2027.42/95464
|url=https://deepblue.lib.umich.edu/bitstream/2027.42/95464/1/jgra21211.pdf| doi-access=free
}}</ref> In certain cases, when solar activity is stronger or in geographical areas such as the [[South Atlantic Anomaly]], the inner boundary may decline to roughly 200 km<ref>{{Cite web |url=http://www.spacewx.com/Docs/ECSS-E-ST-10-04C_15Nov2008.pdf |title=Space Environment Standard ECSS-E-ST-10-04C |date=November 15, 2008 |publisher=ESA Requirements and Standards Division |access-date=2013-09-27 |archive-date=2013-12-09 |archive-url=https://web.archive.org/web/20131209094707/http://spacewx.com/Docs/ECSS-E-ST-10-04C_15Nov2008.pdf |url-status=dead }}</ref> above the Earth's surface. The inner belt contains high concentrations of electrons in the range of hundreds of [[Electronvolt|keV]] and energetic protons with energies exceeding 100 MeV—trapped by the relatively strong magnetic fields in the region (as compared to the outer belt).<ref>{{Cite journal
| author=Gusev, A. A.
| author2=Pugacheva, G. I.
| author3=Jayanthi, U. B.
| author4=Schuch, N.
| title=Modeling of Low-altitude Quasi-trapped Proton Fluxes at the Equatorial Inner Magnetosphere
| journal=Brazilian Journal of Physics | volume= 33 |issue= 4
| date=2003
| pages=775–781
| doi=10.1590/S0103-97332003000400029
| bibcode = 2003BrJPh..33..775G| doi-access=free
}}</ref>

It is thought that proton energies exceeding 50 MeV in the lower belts at lower altitudes are the result of the [[beta decay]] of [[neutron]]s created by cosmic ray collisions with nuclei of the upper atmosphere. The source of lower energy protons is believed to be proton diffusion, due to changes in the magnetic field during geomagnetic storms.<ref>{{Cite book |last=Tascione |first=Thomas F. |title=Introduction to the Space Environment |edition=2nd |date=2004 |publisher=Krieger Publishing Co.| location=Malabar, FL | isbn=978-0-89464-044-5 |oclc=28926928 |lccn=93036569}}</ref>

Due to the slight offset of the belts from Earth's geometric center, the inner Van Allen belt makes its closest approach to the surface at the [[South Atlantic Anomaly]].<ref name="Goddard">{{Cite web |url=http://image.gsfc.nasa.gov/poetry/tour/AAvan.html |title=The Van Allen Belts |publisher=NASA/GSFC |access-date=2011-05-25 |archive-date=2019-12-20 |archive-url=https://web.archive.org/web/20191220163500/https://image.gsfc.nasa.gov/poetry/tour/AAvan.html |url-status=dead }}</ref><ref>{{Cite journal
| author=Underwood, C.
| author2=Brock, D.
| author3=Williams, P.
| author4=Kim, S.
| author5=Dilão, R.
| author6=Ribeiro Santos, P.
| author7=Brito, M.
| author8=Dyer, C.
| author9=Sims, A.
| title=Radiation Environment Measurements with the Cosmic Ray Experiments On-Board the KITSAT-1 and PoSAT-1 Micro-Satellites
| journal=[[IEEE Transactions on Nuclear Science]] | volume=41 |issue=6
| date=December 1994
| pages=2353–2360
| doi=10.1109/23.340587
| bibcode = 1994ITNS...41.2353U}}</ref>

In March 2014, a pattern resembling "zebra stripes" was observed in the radiation belts by the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) onboard [[Van Allen Probes]]. The initial theory proposed in 2014 was that—due to the tilt in Earth's magnetic field axis—the planet's rotation generated an oscillating, weak electric field that permeates through the entire inner radiation belt.<ref>{{Cite news|title=Twin NASA probes find 'zebra stripes' in Earth's radiation belt|url=http://www.universetoday.com/110482/twin-nasa-probes-find-zebra-stripes-in-earths-radiation-belt|work=Universe Today|access-date=20 March 2014|date=2014-03-19}}</ref> A 2016 study instead concluded that the zebra stripes were an imprint of [[Ionospheric dynamo region|ionospheric winds]] on radiation belts.<ref>{{Cite journal
| author=Lejosne, S.
| author2=Roederer, J.G.
| title=The "zebra stripes": An effect of F region zonal plasma drifts on the longitudinal distribution of radiation belt particles
| journal=[[Journal of Geophysical Research]] |volume=121 | issue=1
| doi=10.1002/2015JA021925
| date=2016
| pages=507–518
| bibcode = 2016JGRA..121..507L| doi-access=free
}}</ref>