THE PHYSICS OF THE AURORA AND ITS DETECTION 

PLASMA

First of all, I didn’t quite understand what the sun is even made of to understand what it has to throw at us.  I vaguely remember hearing it was made of plasma, which is pretty much out of my experience besides prodding plasma globes.  Yeah, the sun gives us heat and light.  Yeah, it must throw off other radiation that can give us skin cancer.    But I thought of the sun like a thermal inferno, a volcanic orb.  I pictured the fiery loops of prominences as flung lava.

But watch this NASA video of a prominence in 2012 and notice how the molten spray DOESN'T follow the rules of gravity and fall limply toward the center of the sun like it is supposed to.  Instead, the plasma filaments tightly coil back on themselves as if channeled on an extreme roller coaster track.  Tentacles of plasma stretch out and retreat back at the same impossible angle rather than splatting to the surface.  Plasma is NOT like lava and as you can see through this video, these motions are NOT due to gravity.

Instead, this plasma is following the rules of magnetism. 

Did you know that ALMOST ALL OF THE VISIBLE UNIVERSE is plasma?  It makes sense, since what we can see of the universe is mainly stars and some plasma tendrils between them.   Rather than having normal little planetary-model hydrogen and helium molecules like a normal gas, plasma has all of its charged protons and electrons ripped apart, forming an ionized, electromagnetically volatile soup.  The protons (mainly loner hydrogen and helium duos in the sun) still cling together, bereft of  their electrons in this magnetic flux. The most important thing to understand is that plasma is composed of CHARGED particles blindly responding to magnetic fields.

Like many modern humans, my experiences with (largely low-temperature) plasma include:  buying compact fluorescents, identifying venues by neon-light letters, counting the seconds after seeing lightning, and poking at plasma balls in novelty shops.   Life exists because of our high-temperature plasma star, but I had only peeked at eclipses through black and white film and identified constellations.   I didn't understand that most of the roiling solar surface is due to magnetic fields twisting, shearing, and interacting.  The sun's rotation further twists and stretches these magnetic fields, since the plasma near the poles rotates slower than at the equator (see image below)  [1]  

Jose Francisco Salgado, Adler Planetarium http://ibex.swri.edu/students/How_does_the_Sun.shtml

And finally, I didn't understand that the surface magnetic activity of the sun is correlated with earth's climate.  The fusion cauldron may be burning, but the last time we went 50 years with low sunspot (read low magnetic) activity, Europe experienced the "Little Ice Age"  or the Maunder Minimum 1645-1715.  Snow remained on the ground year-round.  [2] The reliability of aurora borealis activity may be important for steady Japanese winter tourism, but is more importantly an indicator of ongoing solar warmth.