Dogacan Ozturk

Abstract Extreme space weather events on Earth occur during intervals of strong solar wind driving1. The solar wind drives plasma convection and currents in the near-Earth space environment2. For low values of the driver, the Earth’s response is linear, estimated by parameters such as the polar cap index based on ground magnetometer activity3. Curiously, for extreme solar wind driving, the Earth’s response appears not to increase beyond a saturation limit4.

The ionosphere, the ionized layer of Earth’s atmosphere far above the stratosphere, plays vital roles in many applications of modern technology. Radio signals travel through the ionosphere, for example, as do some spacecraft. Space weather events that direct energetic charged particles and radiation from the Sun toward Earth interact with the ionosphere, and even moderate space weather events can cause ionospheric conditions to change substantially.

Sudden commencement (SC) induced by solar wind pressure enhancement can produce significant global impact on the coupled magnetosphere-ionosphere (MI) system, and its effects have been studied extensively using ground magnetometers and coherent scatter radars. However, very limited observations have been reported about the effects of SC on the ionospheric plasma.