The Sun and the solar wind are sources of space weather disturbances in the geospace environment. During the declining phases of solar cycles, the solar wind high-speed streams (HSSs) are a dominant phenomenon, even though they appear at all phases of the solar cycle. HSSs originate from the coronal holes on the Sun and during their travel in the interplanetary space, HSSs interact with the slow solar wind, generating co-rotating interaction regions (CIRs). The effect of HSS/CIRs on the terrestrial upper atmosphere is a complicated and poorly understood process, which involves flow of mass and energy from the Sun, interaction with the Earth’s magnetosphere, and final entry of energy into the ionosphere-thermosphere (I-T) system in different forms including particle precipitation and Poynting flux.
In this project, the focus is in understanding the effect of HSS/CIR-driven geomagnetic storms and associated substorms, first on the high-latitude I-T system, which is the region directly driven by the solar wind. From there, the changes in the whole I-T system may spread to middle and even to low latitudes. Both the role of high-latitude processes producing pronounced changes in the ionospheric (e.g. electron density depletions and increases) and thermospheric (e.g. composition changes) parameters as well as the latitudinal coupling of processes are still poorly known.
The team with expertise ranging from ionospheric and thermospheric measurements and state-of-the-art data analysis to modeling will produce at least two scientific papers in the leading journals of the field.