Science Daily: Cluster Spacecraft Takes First Look at Charged Particles That Drive Brightest Aurora.
ScienceDaily (Apr. 13, 2010) — Using the Cluster spacecraft, scientists from University College London (UCL) have made the first direct observations of charged particles that lead to some of the brightest aurora.
Dr Colin Forsyth presented the results at the RAS National Astronomy Meeting (NAM2010) in Glasgow on April 12.
The aurora, or northern and southern lights, are caused by highly energetic charged particles, normally held in space by Earth's magnetic field, colliding with Earth's upper atmosphere. As these high-energy particles collide with molecules in the atmosphere they lose energy, causing the atmospheric molecules to glow and heating the atmosphere. The result of is spectacular displays of shimmering curtains of red, green and blue light normally seen above the polar regions, but occasionally seen as far south as northern England.
Despite their frequent occurrence, there are still many questions regarding the physical processes behind the aurora. The particles that excite the aurora are accelerated up to high energies in a region extending to around 50 000 km (31 000 miles) above the atmosphere. By understanding the accelerating processes in this region, scientists hope to further understand the aurora.