Abstract
The Naval Research Laboratory (NRL) Sami3 is Also a Model of the Ionosphere (SAMI3) ionosphere/plasmasphere code is used to examine H+, He+, N+, and O+ thermal outflows during a storm. Here, H+ and He+ outflows are associated with refilling while O+ and N+ outflows are associated with ring current heating. An improved model of counterstreaming H+ outflows from the two hemispheres is presented, using an implementation of SAMI3 with two fluid species for H+. The two-fluid H+ model avoids nonphysical high-altitude “top-down refilling” density peaks seen in one-fluid H+ simulations. Counterstreaming cold ion populations are found in all cases. In these fully three-dimensional simulations with realistic magnetosphere boundary conditions, nonphysical top-down refilling density peaks were milder than those found in previous single-field-line or single-magnetic-longitude simulations. In the present two-fluid H+ case, “bottom-up refilling” density peaks were so mild as to be difficult to detect. For O+ and N+, the nonphysical high-altitude density peak is a brief (1–2 h) transient that occurs when heating-driven northward and southward flows first meet. In general, He+ outflows mimic H+ outflows while N+ outflows mimic O+ outflows.
Highlights
Because the plasmasphere (Carpenter, 1966; Nishida, 1966) is an important component of space weather (Lichtenberger et al, 2013), there is significant interest (Gallagher and Comfort, 2016) in the development of predictive models
Test runs (Krall and Huba, 2019) using the Naval Research Laboratory (NRL) Sami2 is Another a Model of the Ionosphere (SAMI2) ionosphere/plasmasphere code (Huba et al, 2000b) code show that a two-fluid description of H+ dramatically improves modeling of earlystage refilling in comparison to the usual one-fluid description
In the simulations presented below, we show that two-fluid H+ does improve the modeling, but the effect is not as dramatic as that found in the test-case modeling of Krall and Huba 2019 and the prior single-field-line simulations of Banks et al 1971 and Singh et al (1986)
Summary
Because the plasmasphere (Carpenter, 1966; Nishida, 1966) is an important component of space weather (Lichtenberger et al, 2013), there is significant interest (Gallagher and Comfort, 2016) in the development of predictive models. One problem with fluid-code plasmasphere simulations is that the H+ fluid tends to outflow from the north and south, colliding nonphysically near the apex (Banks et al, 1971; Richards et al, 1983; Singh et al, 1986). These outflows occur during the refilling of plasmasphere flux tubes (Sojka and Wrenn, 1985; Su et al, 2001; Dent et al, 2006; Sandel and Denton, 2007) following the erosion (Park, 1973; Foster et al, 2014) of the plasmasphere by a geomagnetic storm.
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 call
