Editing Van Allen radiation belt (section)

==Research==
[[File:Jupiter radio.jpg|thumb|Jupiter's variable radiation belts]]
The NASA [[Van Allen Probes]] mission aims at understanding (to the point of predictability) how populations of [[Relativistic electron beam|relativistic electron]]s and ions in space form or change in response to changes in [[solar activity]] and the solar wind.
[[NASA Institute for Advanced Concepts]]–funded studies have proposed magnetic scoops to collect [[antimatter]] that naturally occurs in the Van Allen belts of Earth, although only about 10 micrograms of [[antiproton]]s are estimated to exist in the entire belt.<ref>{{cite web |url=http://www.niac.usra.edu/files/studies/abstracts/1071Bickford.pdf |title=Extraction of Antiparticles Concentrated in Planetary Magnetic Fields |last=Bickford |first=James |publisher=NASA/[[NASA Institute for Advanced Concepts|NIAC]] |access-date=2008-05-24}}</ref>

The Van Allen Probes mission successfully launched on August 30, 2012. The primary mission was scheduled to last two years with expendables expected to last four. The probes were deactivated in 2019 after running out of fuel and are expected to [[deorbit]] during the 2030s.<ref>{{cite web|date=August 30, 2012|editor-last=Zell|editor-first=Holly|title=RBSP Launches Successfully—Twin Probes are Healthy as Mission Begins|url=http://www.nasa.gov/mission_pages/rbsp/news/rbsp-launchnews.html|access-date=2012-09-02|publisher=NASA|archive-date=2019-12-14|archive-url=https://web.archive.org/web/20191214001312/https://www.nasa.gov/mission_pages/rbsp/news/rbsp-launchnews.html|url-status=dead}}</ref> NASA's [[Goddard Space Flight Center]] manages the [[Living With a Star]] program—of which the Van Allen Probes were a project, along with [[Solar Dynamics Observatory]] (SDO). The [[Applied Physics Laboratory]] was responsible for the implementation and instrument management for the Van Allen Probes.<ref>{{cite web |url=http://rbsp.jhuapl.edu/newscenter/intheloop/2010_01.php |archive-url=https://archive.today/20120724194220/http://rbsp.jhuapl.edu/newscenter/intheloop/2010_01.php |url-status=dead |archive-date=2012-07-24 |title=Construction Begins! |date=January 2010 |website=The Van Allen Probes Web Site |publisher=[[Applied Physics Laboratory|The Johns Hopkins University Applied Physics Laboratory]] |access-date=2013-09-27 }}</ref>

Radiation belts exist around other planets and moons in the [[Solar System]] that have magnetic fields powerful and stable enough to sustain them. Radiation belts have been detected at [[Jupiter]], [[Saturn]], [[Uranus]] and [[Neptune]] through in-situ observations, such as by the ''[[Galileo (spacecraft)|Galileo]]'' and ''[[Juno (spacecraft)|Juno]]'' spacecraft at Jupiter, ''[[Cassini–Huygens]]'' at Saturn, and fly-bys from the [[Voyager program]] and [[Pioneer program]]. Observations of radio emissions from highly energetic particles that are trapped in a planets magnetic field have also been used to remotely detect radiation belts, including at Jupiter <ref>{{Cite journal |last1=Drake |first1=F. D. |last2=Hvatum |first2=S. |date=1959 |title=Non-thermal microwave radiation from Jupiter. |url=http://adsabs.harvard.edu/cgi-bin/bib_query?1959AJ.....64S.329D |journal=The Astronomical Journal |volume=64 |pages=329 |doi=10.1086/108047|bibcode=1959AJ.....64S.329D }}</ref> and at the ultracool dwarf [[LSR J1835+3259]].<ref>{{Cite journal |last1=Kao |first1=Melodie M. |last2=Mioduszewski |first2=Amy J. |last3=Villadsen |first3=Jackie |last4=Shkolnik |first4=Evgenya L. |date=July 2023 |title=Resolved imaging confirms a radiation belt around an ultracool dwarf |journal=Nature |language=en |volume=619 |issue=7969 |pages=272–275 |doi=10.1038/s41586-023-06138-w |issn=1476-4687 |pmc=10338340 |pmid=37187211|arxiv=2302.12841 |bibcode=2023Natur.619..272K }}</ref> It is possible that [[Mercury (planet)]] may be able to trap charged particles in its magnetic field,<ref>{{Cite journal |last1=Lukashenko |first1=A. T. |last2=Lavrukhin |first2=A. S. |last3=Alexeev |first3=I. I. |last4=Belenkaya |first4=E. S. |date=2020-11-01 |title=Possibility of the Existence of Trapped Radiation near Mercury |url=https://link.springer.com/article/10.1134/S1063773720110043 |journal=Astronomy Letters |language=en |volume=46 |issue=11 |pages=762–773 |doi=10.1134/S1063773720110043 |bibcode=2020AstL...46..762L |issn=1562-6873}}</ref> although its highly dynamic magnetosphere (which varies on the order of minutes <ref>{{Cite journal |last1=Sun |first1=Wei-Jie |last2=Slavin |first2=James A. |last3=Fu |first3=Suiyan |last4=Raines |first4=Jim M. |last5=Zong |first5=Qiu-Gang |last6=Imber |first6=Suzanne M. |last7=Shi |first7=Quanqi |last8=Yao |first8=Zhonghua |last9=Poh |first9=Gangkai |last10=Gershman |first10=Daniel J. |last11=Pu |first11=Zuyin |last12=Sundberg |first12=Torbjörn |last13=Anderson |first13=Brian J. |last14=Korth |first14=Haje |last15=Baker |first15=Daniel N. |date=2015 |title=MESSENGER observations of magnetospheric substorm activity in Mercury's near magnetotail |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2015GL064052 |journal=Geophysical Research Letters |language=en |volume=42 |issue=10 |pages=3692–3699 |doi=10.1002/2015GL064052 |bibcode=2015GeoRL..42.3692S |issn=1944-8007|hdl=2027.42/111983 |hdl-access=free }}</ref>) may not be able to sustain stable radiation belts. [[Venus]] and [[Mars]] do not have radiation belts, as their magnetospheric configurations do not trap energetic charged particles in orbit around the planet.

[[Geomagnetic storm]]s can cause electron density to increase or decrease relatively quickly (i.e., approximately one day or less). Longer-timescale processes determine the overall configuration of the belts. After electron injection increases electron density, electron density is often observed to decay exponentially. Those decay time constants are called "lifetimes." Measurements from the Van Allen Probe B's Magnetic Electron Ion Spectrometer (MagEIS) show long electron lifetimes (i.e., longer than 100 days) in the inner belt; short electron lifetimes of around one or two days are observed in the "slot" between the belts; and energy-dependent electron lifetimes of roughly five to 20 days are found in the outer belt.<ref>{{Cite journal|doi = 10.1029/2019GL086053|title = Empirically Estimated Electron Lifetimes in the Earth's Radiation Belts: Van Allen Probe Observations|year = 2020|last1 = Claudepierre|first1 = S. G.|last2 = Ma|first2 = Q.|last3 = Bortnik|first3 = J.|last4 = O'Brien|first4 = T. P.|last5 = Fennell|first5 = J. F.|last6 = Blake|first6 = J. B.|journal = Geophysical Research Letters|volume = 47|issue = 3|pages = e2019GL086053|pmid = 32713975|pmc = 7375131|bibcode = 2020GeoRL..4786053C}}</ref>