The Earth's upper atmosphere is ionized by radiations, both electromagnetic and corpuscular, from the Sun. The electromagnetic radiations, such as radio, infrared, visible, ultraviolet, extreme ultraviolet, and X-rays, travel directly between Sun and Earth at the free space speed with a transit time of about 8-3 minutes. The region between and including Sun and Earth has these components: the Sun, the interplanetary medium, the Earth's magnetosphere, the Earth's neutral atmosphere, and the Earth's ionosphere as depicted in Fig. 2.1. Understanding the features of the solar-terrestrial system discussed in this Chapter is essential to an understanding of the spatial and temporal structure of the ionosphere.

Inspec keywords: interplanetary matter; solar radiation; ionosphere; magnetosphere; Sun

Other keywords: solar-terrestrial relationship; electromagnetic radiation; Earth upper atmosphere; corpuscular radiation; neutral atmosphere; magnetosphere; ionosphere; Sun; interplanetary medium

Subjects: Magnetospheric interaction with solar wind