Black Auroral Vortices
Lens: 105 mm, f/1.8.
We note that black vortices curl up in the clockwise direction as opposed to
ordinary auroral curls.
black aurora: a lack of emission in well-defined regions
within an otherwise uniform, diffuse emission. - T. N. Davis, 1978
"Black aurora appear to be forbidden regions in the aurora." - O. Royrvik, 1976
Last modified March 7, 1996 by Trond S. Trondsen (trondsen@phys.ucalgary.ca)