This causes auroras to brighten and fade with time. In addition the charged particles that travel poleward along Earth's field lines create their own electromagnetic fields that deform those of Earth thus distorting the auroras.
Auroras move toward the equator as intense solar winds penetrate deeper into the magnetosphere.
Figure 2 shows how charged particles reaching closer to Earth travel along field lines that cross the surface nearer to the equator. Figures 3 and 4 show images of auroras in Alaska. All rights reserved.