UCLA EPSS research findings are featured on the February 2017 cover of the Journal of Geophysical Research: Space Physics. The study describes the properties of a newly discovered form of the northern lights, called throat aurora, on the dayside of Earth facing the sun. Using observations on the ground and in interplanetary space, the aurora are postulated to form through a novel combination of plasma flows inside and outside of the Earth's magnetic field (the magnetosphere). Under certain conditions, solar wind interactions at the bow shock (~2 Earth widths upstream of the magnetosphere) can produce fast jets of hot plasma that perturb the outer boundary of the magnetosphere, as shown by previous UCLA EPSS studies. Sometimes cooler plasma "fingers" within Earth's magnetosphere extend outward towards this boundary. The interaction of these two plasmas manifests as throat aurora, with radial spokes uniquely aligned along the north-south longitudinal axis.
Image credit: E. Masongsong, H. Hietala (UCLA EPSS), D.-S. Han (Polar Research Institute of China).