Detection of multiple small plasmoids in the magnetotail



Magnetic field lines in the Earth's dayside magnetic field can be broken down and swept to the Earth's nightside by the solar wind. The magnetic field lines reconnect in the magnetotail, in some cases triggering a magnetic substorm. During a substorm, plasma trapped in the magnetotail is sent flowing toward the Earth, and the magnetotail current sheet—the region where magnetic field lines from the Earth's North and South Poles come together—gets thinner.