Global view of inner magnetosphere composition during storm time

Abstract

[1] Plasma dynamics in the inner magnetosphere are greatly affected by variations in the ion composition. The ratio of hydrogen to oxygen has been shown to be highly dependent on geomagnetic activity. To investigate this dependence, we examine the timing of the injection and subsequent evolution of O + in the ring current during the storm of 6 August 2011 as observed by Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) instruments. To help interpret magnetospheric evolution using the global O Energetic Neutral Atom (ENA) emission measured by TWINS, we have employed a multidomain modeling of the global magnetosphere using the Space Weather Modeling Framework. TWINS Energetic Neutral Atom (ENA) imagers have the capability to distinguish between H and O emission and thus the major ion constituents of the ring current. Global composition measurements from TWINS spacecraft show intensifications of the oxygen ENA emission and thus an increase in the transport of ionospheric oxygen into the ring current that occur during the main phase of the storm. Both the observations and the simulation suggests that the peak in O ENA emission is correlated with the substorm injections that occurred during this time. The model also shows a very dynamic magnetosphere that allows for loss of oxygen from the Earth-magnetosphere system through plasmoids capable of transporting oxygen down the tail throughout the magnetic storm. This can possibly be a predominant pathway for loss of oxygen from the magnetosphere.Citation: Ilie, R., R. M. Skoug, P. Valek, H. O. Funsten, and A. Glocer (2013), Global view of inner magnetosphere composition during storm time,

The outflow of ionospheric nitrogen ions: A possible tracer for the altitude‐dependent transport and energization processes of ionospheric plasma

“…Since first suggested by Shelley et al [], the dynamics leading to the ionospheric outflow of O + ions and the impact on the evolution of the magnetosphere‐ionosphere system have been the subject of numerous studies [e.g., Schunk and Raitt , ; Mukai et al , ; Schunk and Sojka , ; Seki et al , ; Daglis et al , ; Winglee et al , ; Nosé et al , ; Barakat and Schunk , ; Glocer et al , ; Garcia et al , ; Glocer et al , ; Ilie et al , , ]. For instance, several studies [e.g., Young et al , ; Hamilton et al , ; Daglis et al , ; Fu et al , , ; Winglee et al , ; Kozyra et al , ; Nosé et al , ] find that O + can dominate not only the mass density but even the number density in the magnetosphere, therefore controlling the large‐scale processes of mass and energy flow through geospace.…”

The Big Picture: Imaging of the Global Geospace Environment by the TWINS Mission

“…Global regions of O + were found to comprise islands of smaller structure. Ilie, Skoug, Valek, et al () compared TWINS oxygen images with a global model and found that plasmoids may be a major mechanism for O + transport and loss.…”

“…Physics‐based models offer a means of interpreting the images to discover which mechanisms are controlling the dynamics. Numerous TWINS‐based studies have included global models in this way (Buzulukova et al, ; Fok et al, ; Glocer et al, ; Ilie, Skoug, Valek, et al, ; McComas et al, ).…”

“…The importance of model‐supported interpretation continues to be demonstrated for studies of ion composition and temperature. The BATSRUS and BATSRUS‐CRCM global models have helped to show that O + concentration can affect the strength of the ring current (Glocer et al, ) and that the predominant pathway for O + loss may be plasmoids transporting these ions down the magnetotail (Ilie, Skoug, Valek, et al, ). Keesee, Elfritz, et al () used CRCM runs to interpret the results of their superposed epoch analysis of TWINS temperature maps.…”

The two‐way relationship between ionospheric outflow and the ring current

“…During periods of strong solar driving, O + of ionospheric origin drastically increases in the plasma sheet and geosynchronous locations [e.g., Young et al , ; Lennartsson and Shelley , ; Nosé et al , ; Nosé , ; Denton et al , ] and the inner magnetosphere [ Sharp et al , ; Hamilton et al , ; Daglis et al , ; Kozyra , ; Kronberg et al , ]. Ring current modelers have switched from using basic empirical models of plasma sheet composition [e.g., Fok et al , ; Jordanova et al , ; Kozyra et al , ; Liemohn et al , ; Ebihara and Ejiri , ; Jordanova et al , ] to dynamic, physics‐based models that capture the evolution from outflow to plasma sheet [ Moore , ; Moore et al , ; Fok et al , ; Welling et al , ; Ilie et al , ]. It has been found that spatial and temporal dynamics of the ionospheric source are important in controlling ring current development and are distinct from the solar source.…”