Phys.org  October 30, 2023
Both solar wind and ionospheric sources contribute to the magnetotail plasma sheet, but how their contribution changes during a geomagnetic storm is an open question. The source is critical because the plasma sheet properties control the enhancement and decay rate of the ring current, the main cause of the geomagnetic field perturbations that define a geomagnetic storm. An international team of researchers (USA – University of New Hampshire, Lockheed Martin Advanced Technology Center, Harvard-Smithsonian Center for Astrophysics, Japan) used the solar wind composition to track the source and showed that the plasma sheet source changed from predominantly solar wind to predominantly ionospheric as a storm developed. They found that the ionospheric plasma during the storm main phase was initially dominated by singly ionized hydrogen likely from the polar wind, a low energy outflow from the polar cap, and then transitioned to the accelerated outflow from the dayside and nightside auroral regions, identified by singly ionized oxygen. According to the researchers these results reveal how the access to the magnetotail of the different sources can change quickly, impacting the storm development… read more. Open Access TECHNICAL ARTICLE
Solar wind and ionospheric sources of the plasma sheet. Credit: Nature Communications volume 14, Article number: 6143, 30 October 2023Â