Editing Magnetic reconnection (section)

===Earth's magnetosphere===

Magnetic reconnection events that occur in the Earth's [[magnetosphere]] (in the dayside [[magnetopause]] and in the [[magnetotail]]) were for many years inferred because they uniquely explained many aspects of the large-scale behaviour of the magnetosphere and its dependence on the orientation of the near-Earth [[Interplanetary magnetic field]]. Subsequently, spacecraft such as [[Cluster mission|Cluster II]]<ref>[http://clusterlaunch.esa.int/science-e/www/area/index.cfm?fareaid=8 Articles on measurements made from the Cluster II spacecraft mission]</ref> and the [[Magnetospheric Multiscale Mission]].<ref>{{Cite journal|last1=Burch|first1=J. L.|last2=Torbert|first2=R. B.|last3=Phan|first3=T. D.|last4=Chen|first4=L.-J.| last5=Moore|first5=T. E.|last6=Ergun|first6=R. E.|last7=Eastwood|first7=J. P.|last8=Gershman|first8=D. J.| last9=Cassak|first9=P. A.|date=2016-06-03|title=Electron-scale measurements of magnetic reconnection in space| journal=Science| language=en| volume=352| issue=6290| pages=aaf2939| doi=10.1126/science.aaf2939| issn=0036-8075| pmid=27174677| bibcode=2016Sci...352.2939B| hdl=10044/1/32763| s2cid=206647580| doi-access=free|hdl-access=free}}</ref> have made observations of sufficient resolution and in multiple locations to observe the process directly and in-situ. Cluster II is a four-spacecraft mission, with the four spacecraft arranged in a tetrahedron to separate the spatial and temporal changes as the suite flies through space.  It has observed numerous reconnection events in which the Earth's magnetic field reconnects with that of the Sun (i.e. the [[Interplanetary Magnetic Field]]). These include 'reverse reconnection' that causes sunward convection in the Earth's [[ionosphere]] near the polar cusps; 'dayside reconnection', which allows the transmission of particles and energy into the Earth's vicinity and 'tail reconnection', which causes auroral [[substorm]]s by injecting particles deep into the magnetosphere and releasing the energy stored in the Earth's magnetotail.  The [[Magnetospheric Multiscale Mission]], launched on 13 March 2015, improved the spatial and temporal resolution of the Cluster II results by having a tighter constellation of spacecraft. This led to a better understanding of the behavior of the electrical currents in the electron diffusion region.

On 26 February 2008, [[THEMIS]] probes were able to determine the triggering event for the onset of magnetospheric substorms.<ref>{{cite web|url=http://www.nasa.gov/mission_pages/themis/auroras/themis_power.html|title=THEMIS Satellites Discover What Triggers Eruptions of the Northern Lights|website=NASA|date=7 June 2013}}</ref> Two of the five probes, positioned approximately one third the distance to the Moon, measured events suggesting a magnetic reconnection event 96 seconds prior to auroral intensification.<ref>{{cite journal|title=Tail Reconnection Triggering Substorm Onset| author=Vassilis Angelopoulos| doi=10.1126/science.1160495| pmid=18653845|volume=321| issue=5891| pages=931–935| journal=Science|bibcode = 2008Sci...321..931A |year=2008|s2cid=206514133| doi-access=free}}</ref> Dr. Vassilis Angelopoulos of the University of California, Los Angeles, who is the principal investigator for the THEMIS mission, claimed, "Our data show clearly and for the first time that magnetic reconnection is the trigger.".<ref>{{cite web|url=http://www.space.com/scienceastronomy/080724-themis-aurora-mystery.html|title=Secret of Colorful Auroras Revealed|website=Space.com|date=24 July 2008}}</ref>