Sped up video of the substorm onset over Ely, MN tonight. You can see beads propagating eastward then forming the poleward expanding aurora which moved north with rapid motion and energetic precipitation resulting in white/pink nitrogen fringing at the bottom of the curtain. Auroral beads are associated with an instability that forms when Earth's magnetotail becomes too stretched out. Like pulling an old rope until the strands start to fray and unravel, inside Earth's magnetosphere, a pressure g