Investigating High‐Latitude Energy Deposition Events Occurring During the 17 January 2005 Geomagnetic Storm

Abstract

AbstractThis study investigates the coupled ionosphere‐thermosphere system during the 17 January 2005 geomagnetic storm. Multiinstrument satellite data are utilized to track polar convection and flow channels (FCs) in the topside ionosphere to compute Poynting flux values approximating electromagnetic energy and to detect localized neutral density increases and also to signal FC signatures in the thermosphere. Our main aim is to identify energy input regions during various events when localized neutral density increases developed. Such events are illustrated in five scenarios covering both hemispheres. These scenarios demonstrate the development of a cusp enhancement above/within FC‐1 associated with newly open field lines and polar cap enhancements above/within FC‐2, FC‐3, and FC‐4 commonly associated with old open field lines. Localized Poynting flux intensifications within these FCs demonstrate energy deposition continuing along old open field lines in the polar cap. The close correlation of these Poynting flux intensifications with their respective cusp and polar cap enhancements, via their underlying FCs through which the electromagnetic energy was deposited, provide observational evidence that these enhancements were generated by their associated energy inputs. These observational results lead to the conclusions that a main region of high‐latitude energy deposition was (i) the polar cap (>78° magnetic latitude) producing polar cap enhancements (scenarios 1–3), (ii) the prenoon auroral zone producing a cusp enhancement (scenario 4), and (iii) both the polar cap producing a polar cap enhancement and the auroral zone (scenario 5).