ionosphere

noun

1. The part of the Earth's atmosphere beginning at an altitude of about 50 kilometers (31 miles) and extending outward 500 kilometers (310 miles) or more.

   “Dave frowned as he tried to answer. "Well, I suppose the atmosphere is oxygen and nitrogen, mostly; then there's the ionosphere and the ozone layer. As I remember, the color of the sky is due to the scattering of light—light rays being diffracted in the air."”

   “Solar storms drive currents of millions of amps through the electrically conductive upper layer of our atmosphere (known as the ionosphere). These currents, which can fluctuate rapidly, drive powerful magnetic disturbances at the Earth's surface that in turn induce electrical currents in the planet's crust.”

2. The similar region of the atmosphere of another planet.