2) The particles in the solar wind is captured by the earths magnetic field. Gathered in the night side of the earths magneto sphere and then accellereted along the open magnetic field lines down to the polar regions. They hit the earth in a narrow belt called the northern lights oval.
3) Seen from space, the northern lights can hang down like a carpet or like draperies. Upper edge red, lower violet and blue, and green in the middle.
4) The aurora activity occurs both around the north pole and the south pole at the same time. Around the south pole it is called the southern lights. Photographs taken from aeroplanes verifies that the patterns are symmetrical.
5) The first indication of a northern lights display is faint glow low on the horizon.
6) The faint glow dies out, but after a while an arch of light is lit. It can stretch all over the sky.
7) Bands of northern lights one above the other, raising towards the zenith indicates that the sub storm is starting.
8) Rays of light shoot down from space tells about higher activity.
9) Draperies are formed with waves at the lower end.
10) Curls and waves wave along the draperies.
11) The draperies look as if they are flickering in the wind. Maximum activityis close.
12) The interaction between the moving charged particles and the earths magnetic field creates a charging magnetic field. The particles stream down along the magnetic field lines.
13) Rays and draperies can die out in one place of the sky,
14) and form at another.
15, 16) During the maximum of a sub storm, the whole sky can be full of light.
17) An all-sky (fish eye) picture showing that the draperies are stretched from east to west, through zenith.
18) When the activity reaches Zenith, by an optical illusion, it seems like the rays stretch out in all directions above our heads. This form of the northern lights is called aurora corona.
