Abstract
The impact of the dynamic evolution of the Storm-Enhanced Density (SED) on the upward ion fluxes during the March 06, 2016 geomagnetic storm is studied using comprehensive multi-scale datasets. This storm was powered by a Corotating Interaction Region (CIR), and the minimum Sym-H reached ∼−110 nT. During the ionospheric positive storm phase, the SED formed and the associated plume and polar cap patches occasionally drifted anti-sunward across the polar cap. When these high-density structures encountered positive vertical flows, large ion upward fluxes were produced, with the largest upward flux reaching 3 × 1014 m−2s−1. These upflows were either the type-1 ion upflow associated with fast flow channels, such as the subauroral polarization stream (SAPS) channel, or the type-2 ion upflow due to soft particle precipitations in the cusp region. The total SED-associated upflow flux in the dayside cusp can be comparable to the total upflow flux in the nightside auroral zone despite the much smaller cusp area compared with the auroral zone. During the ionospheric negative storm phase, the ionospheric densities within the SED and plume decreased significantly and thus led to largely reduced upward fluxes. This event analysis demonstrates the critical role of the ionospheric high-density structures in creating large ion upward fluxes. It also suggests that the dynamic processes in the coupled ionosphere-thermosphere system and the resulting state of the ionospheric storm are crucial for understanding the temporal and spatial variations of ion upflow fluxes and thus should be incorporated into coupled geospace models for improving our holistic understanding of the role of ionospheric plasma in the geospace system.
Highlights
The Earth’s ionosphere is a crucial plasma source for the magnetosphere, in particular for heavy ions such as O+ (e.g., Yau et al, 2011; Moore and Horwitz, 2007; Lotko 2007; Welling et al, 2015; Chappell, 2015 and references therein)
We evaluated the impact of the SED dynamic evolution on the upward ion fluxes during the March 06, 2016 geomagnetic storm using comprehensive multi-scale datasets
Even under similar convection and particle precipitation conditions, the reduced ionospheric density during the negative storm phase led to weakened upward fluxes. This event analysis demonstrates the critical role of the SED and SED plume in creating large ion upward fluxes
Summary
The Earth’s ionosphere is a crucial plasma source for the magnetosphere, in particular for heavy ions such as O+ (e.g., Yau et al, 2011; Moore and Horwitz, 2007; Lotko 2007; Welling et al, 2015; Chappell, 2015 and references therein). We analyzed the evolution of the SED and plume using global TEC, convection and field-aligned currents (FACs) data, and its impact on the ion upflow fluxes measured by the DMSP satellites during March 06, 2016, geomagnetic storm. The PFISR radar is part of the NSF-supported advanced modular incoherent scatter radar (AMISR) facility that is used to conduct studies of the upper atmosphere and to observe space weather events It can simultaneously measure the altitude profiles of important ionospheric parameters, such as electron density, electron/ion temperatures, and line-of-sight ion velocity. The TIMED satellite was in the early afternoon to postmidnight orbital plane, which is ideal to observe the thermosphere composition change impact on the SED
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
