Browsing by Author "Stoneback, Russell"

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    Modeling the daytime, equatorial ionospheric ion densities associated with the observed, four‐cell longitude patterns in E × B drift velocities
    (American Geophysical Union, 2012-04-26) Araujo-Pradere, Eduardo A.; Fang, Tzu Wei; Anderson, David N.; Fedrizzi, Mariangel; Stoneback, Russell
    Previous studies have quantified the longitude gradients in E × Bdrift associated with the four‐cell tidal structures and have confirmed that these sharp gradients exist on a day‐to‐day basis. For this paper, we incorporate the Ion Velocity Meter (IVM) sensor on the Communications/Navigation Outage Forecasting System satellite to obtain the daytime, verticalE × B drift velocities at the magnetic equator as a function of longitude, local time, and season and to theoretically calculate the F region ion densities as a function of altitude, latitude, longitude, and local time using the Global Ionosphere Plasmasphere model. We compare calculated ion densities assuming no longitude gradients in E × Bdrift velocities with calculated ion densities incorporating the IVM‐observedE × Bdrift at the boundaries of the four‐cell tidal structures in the Peruvian and the Atlantic longitude sectors. Incorporating the IVM‐observedE × B drift velocities, the ion density crests rapidly converge to the magnetic equator between 285 and 300°E geographic longitude, are absent between 300° and 305°, and move away from the magnetic equator between 305° and 340°. In essence, the steeper the longitude gradient in E × B drifts, the steeper the longitude gradient in the equatorial anomaly crest location.
    Palabras clave:Equatorial E×B driftsFour‐cell patternModeling ion density
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    Vertical and meridional equatorial ion flows observed by CINDI during the 26 September 2011 storm
    (American Geophysical Union, 2013-08-06) Hairston, Marc R.; Coley, W. Robin; Stoneback, Russell
    The equatorial ionosphere is generally shielded from outside electrical fields except during large geomagnetic storms. During these storms, the polar region electric fields can temporarily extend to the equatorial regions in what is called a penetration field. During the subsequent recovery period, a disturbance dynamo is produced with an enhanced electric field with the opposite orientation relative to the penetration field. The penetration electric field would be oriented toward the east on the dayside causing an excess upward E × B motion of the equatorial ionospheric ions. The disturbance dynamo electric field would have the opposite orientation, westward on the dayside, producing an excess downward E × B motion of the equatorial ionospheric ions. The moderate storm (minimum Dst = −103 nT) on 26 September 2011 is examined using ion flow data from the Coupled Ion‐Neutral Dynamics Investigation (CINDI) thermal plasma instrument package on the Communication/Navigation Outage Forecast System (C/NOFS) spacecraft on the dayside and early evening local times to look for examples of these flows. Despite what should have been a large enough storm to produce penetration fields and upward flows, a detailed examination of the observed flows from this storm shows only enhanced downward flows before the storm, during the main phase, and through the recovery.
    Palabras clave:CINDIEquatorialIonosphere