I'm writing an article on the 1859 event of a direct hit on Planet Earth of a solar flare, triggering aurora all across the North Hemisphere, observed as far south as Cuba (!) and Rome (!!)
http://science.nasa.gov/headlines/y2008/06may_carringtonflare.htm
So I'm reading through the archive of the American Science Journal for 1859-1860, which contain the direct observations from countless astronomers and observatories across the August 28th - Sept 2nd period when the Aurora were at their maximum.
http://diva.library.cmu.edu/ajs/browse.jsp?n1=6
And something jumps out at me from all the various reports - the predominance of the colour red in the prominence and curtains.
Aurora we all know operate a bit like the gas in a neon tube - the gasses in the atmosphere glow when they are excited, the magnetic field lines funnel charged particls towards the poles and - hey preto - the atmospheric gasses glow all sorts of colours.
What I wanted to know was why was there so much red?
I did a little digging and found this website:
http://ffden-2.phys.uaf.edu/211.fall2000.web.projects/Christina%20Shaw/AuroraColors.html
Which says all red aurora is Oxygen, higher than 200km and Crimson colouration is neutral Nitrogen below 100km.
Green being the most common colour seen, what I was wondering was this - did the extremely high energies involved in the Super-flare event (as oppose say normal solar winds) have anything to do with either a) exciting oxygen at high altitudes than normal or b) exciting neutral Nitrogen at lower altitudes than normal.
I accept red auroras are fairly common - one of the many ways this event is unique seems to be the distribution of auroral effects and the near universal agreement on the structures, colours and position (everywhere!)
I only registered today with the sole purpose of finding out more about this so can anyone help me?
Thanks.
Richard.