ioonosfääri

The ionosphere is a region of Earth's upper atmosphere, roughly between 60 and 1,000 kilometers (37 to 621 miles) above the surface, where solar radiation ionizes atmospheric gases. This ionization creates a layer of charged particles, or ions, that plays a significant role in radio wave propagation.

The ionosphere is not a uniform layer but is divided into several sub-regions, including the D, E, and F layers, each characterized by different densities of ions and their behavior at varying altitudes. The D layer, the lowest, absorbs most radio waves. The E layer reflects medium-frequency radio waves, while the F layer, the highest, reflects most short-wave radio signals, allowing for long-distance communication.

The density of ions in the ionosphere fluctuates throughout the day and with the seasons due to changes in solar activity. During daylight hours, the sun's ultraviolet and X-ray radiation creates more ions, making the ionosphere denser. At night, as solar radiation diminishes, the ionosphere becomes less dense, and the D layer often disappears.

Variations in the ionosphere, such as ionospheric storms caused by solar flares and coronal mass ejections, can disrupt radio communications, GPS signals, and even power grids. Studying the ionosphere is crucial for understanding space weather and its impacts on technology and human activities.