Type:		Electronic Citation
Title:		NASA Spacecraft Make New Discoveries About Northern Lights
Author(s):		O'Carroll, C.
Date:		2012/06/23
Abstract:		NASA's Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission observed the dynamics of a rapidly developing [geomagnetic] substorm, confirmed the existence of giant magnetic ropes, and witnessed small explosions in the outskirts of Earth's magnetic field. [...] "The satellites have found evidence of magnetic ropes connecting Earth's upper atmosphere directly to the sun," said David Sibeck, project scientist for the mission at NASA's Goddard Space Flight Center, Greenbelt, MD. "We believe that solar wind particles flow in along these ropes, providing energy for geomagnetic storms and auroras." [...] A magnetic rope is a twisted bundle of magnetic fields organized much like the twisted hemp of a mariner's rope. [...] "THEMIS encountered its first magnetic rope on May 20," said Sibeck. "It was very large, about as wide as Earth, and located approximately 70,000 km above Earth's surface in a region called the magnetopause." The magnetopause is where the solar wind and Earth's magnetic field meet and push against one another like sumo wrestlers locked in combat. There, the rope formed and unraveled in just a few minutes, providing a brief but significant conduit for solar wind energy.
Publisher:		NASA
Link:		http://www.nasa.gov/mission_pages/themis/auroras/northern_lights.html