Usually, a disturbance in the solar wind interacts with the magnetic field of the Earth, which causes a re-connection event in the Earth's magnetotail. Like a rubber band snapping, the magnetic field 'sub-storm' accelerates electrons which are channeled to the north and south magnetic poles of the Earth .They arrive with energies near 6000 volts, and this current slams into the atmosphere at a typical elevation of 70 - 100 miles. The interaction between the electrons and the atoms causes the chief constituents, nitrogen and oxygen, to fluoresce like the gas inside fluorescent bulbs. The atoms emit light at only a few specific wavelengths which give aurora their unique colors, blue, red, green..
