brbear1 wrote:The caption to the APOD on 11.18.08 mentions the hexagonal shaped cloud band around the north pole of Saturn. It appears to me that the strange aurora also there overlays this same cloud band. It may be that whatever forces are creating the hexagonal cloud band are also effecting the strange aurora above it in the Saturnian atmosphere.
I don't think that it is any kind of aurora at all!
IMO, It is either some atmospheric phenomenum
akin to lightning or to blue jets or to red sprites:
http://www.spritesandjets.com/
Blue jets
http://en.wikipedia.org/wiki/Lightning#Blue_jets
<<Blue jets differ from sprites in that they project from the top of the cumulonimbus above a thunderstorm, typically in a narrow cone, to the lowest levels of the ionosphere 25 miles (40 km) to 30 miles (48 km) above the earth.[citation needed] They are also brighter than sprites and, as implied by their name, are blue in colour. They were first recorded on October 21, 1989, on a video taken from the space shuttle as it passed over Australia, and subsequently extensively documented in 1994 during aircraft research flights by the University of Alaska.
On September 14, 2001, scientists at the Arecibo Observatory photographed a huge jet double the height of those previously observed, reaching around 50 miles (80 km) into the atmosphere. The jet was located above a thunderstorm over the ocean, and lasted under a second. Lightning was initially observed traveling up at around 50,000 m/s in a similar way to a typical blue jet, but then divided in two and sped at 250,000 m/s to the ionosphere, where they spread out in a bright burst of light. On July 22, 2002, five gigantic jets between 60 and 70 km (35 to 45 miles) in length were observed over the South China Sea from Taiwan, reported in Nature.52] The jets lasted under a second, with shapes likened by the researchers to giant trees and carrots.[citation needed]
In 2001, the Arecibo scientists modeled the blue-jet phenomenon to better understand how it works. It is like an electron avalanche that can flood up toward the ionosphere or slide earthward, depending on the electric field direction. Intense hail may trigger the avalanche. The field accelerates the electrons and slams them into air molecules. The molecules break down into ions and free electrons and emit light. The newly generated electrons also accelerate.>>
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Blue Jets
http://elf.gi.alaska.edu/#chrjet
<<Blue jets are a ... high altitude optical phenomenon, distinct from sprites, observed above thunderstorms using low light television systems. As their name implies, blue jets are optical ejections from the top of the electrically active core regions of thunderstorms. Following their emergence from the top of the thundercloud, they typically propagate upward in narrow cones of about 15 degrees full width at vertical speeds of roughly 100 km/s (Mach 300), fanning out and disappearing at heights of about 40-50 km. Their intensities are on the order of 800 kR near the base, decreasing to about 10 kR near the upper terminus. These correspond to an estimated optical energy of about 4 kJ, a total energy of about 30 MJ, and an energy density on the order of a few mJ/m^3. Blue jets are not aligned with the local magnetic field.>>
http://elf.gi.alaska.edu/
http://umbra.nascom.nasa.gov/spd/sprites.html
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