F-region drift velocities in the dusk sector mid-latitude trough

Scali, J. L.; Reinisch, B. W.

doi:10.1016/0021-9169(94)00112-2

Cited by 3 publications

(3 citation statements)

References 30 publications

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“…The westward ion drift in the SAPS channel that transports the low‐density plasma from the nightside into the afternoon sector may also contribute to the formation of a stronger middle latitude ionospheric density trough in the SAPS‐TIEGCM in the afternoon sector [ Evans et al , 1983; Pirog et al , 2009]. Our results are consistent with previous studies that showed that SAPS are associated with the middle latitude ionospheric plasma density trough [e.g., Anderson et al , 1991, 2001; Foster , et al , 1994; Scali and Reinisch , 1995; Karlsson et al , 1998]. Comprehensive reviews of the main trough can be found in Rodger et al [1992] and Moffett and Quegan [1983].…”

Section: Discussionsupporting

confidence: 90%

“…However, Figure 13b indicates that ionospheric plasma was transported upward vertically by the E Â B drift which might offset the effect of neutral composition. There have been suggestions that eastward ion drifts with high velocities (1000-1200 m/s) can transport the low-density plasma from the night to the morning sector, resulting in an electron density trough [Evans et al, 1983;Foster et al, 1994;Scali and Reinisch, 1995;Pirog et al, 2009]. In our SAPS-TIEGCM simulations, the subauroral eastward drifts in the dawn sector were relatively weak and did not extend beyond 0600 LT (Figure 1a).…”

Section: Ionospheric Electron Density Response To Sapsmentioning

confidence: 70%

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Thermosphere and ionosphere response to subauroral polarization streams (SAPS): Model simulations

Wang¹,

Talaat²,

Burns³

et al. 2012

J. Geophys. Res.

148

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[1] An empirical model of subauroral polarization streams (SAPS) has been incorporated into the Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM). This SAPS driven TIEGCM is used to simulate the effect of SAPS on the global thermosphere and ionosphere during a moderate geomagnetically active period between day of year (DOY) 329 and 333 in 2008. Model results show: (1) SAPS caused an increase in global thermospheric temperature which became stronger with time. This neutral temperature increase was more significant in subauroral and auroral regions. Joule heating by the SAPS and the redistribution of this heat by dynamic processes were the primary mechanisms for the simulated global neutral temperature changes. (2) In the SAPS driven TIEGCM, the strong ion drag effect in the subauroral SAPS channel drove large changes in thermospheric winds. Zonal neutral winds had either an extra, separate channel of westward flow in the subauroral region in the afternoon-midnight sector or a broad westward wind jet that merged with the regular duskside auroral westward zonal neutral wind driven by the high latitude convection pattern. The exact latitudinal profile of the zonal winds depended on local time. (3) The response of neutral temperature and wind to SAPS was more significant at higher altitudes and exhibited seasonal/hemispheric asymmetry. (4) The heating to the thermosphere by SAPS also resulted in changes in thermospheric composition with upwelling of molecular rich air in subauroral and auroral regions and downwelling of atomic oxygen rich air at other latitudes. These changes in thermospheric composition contributed to the deeper and more extended ionospheric electron density depletions in subauroral middle latitude regions, as well as electron density increases along the equatorward edge of the SAPS channel in the afternoon sector.

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Section: Discussionsupporting

confidence: 90%

Section: Ionospheric Electron Density Response To Sapsmentioning

confidence: 70%

Thermosphere and ionosphere response to subauroral polarization streams (SAPS): Model simulations

Wang¹,

Talaat²,

Burns³

et al. 2012

J. Geophys. Res.

148

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show abstract

“…Apart from the ionogram–derived vertical drift velocity, Digisonde estimates the vertical drift velocity directly too by measuring the zonal and vertical motion of the ionospheric echo sources using Doppler interferometry (Reinisch et al., 1998). Doppler spectra from the four receiver antennae are post–processed with Digisonde Drift Analysis (DDA) software to get the drift velocity (J. L. Scali, 1993; J. L. Scali & Reinisch, 1995; J. Scali et al., 1995). Anderson et al.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Study on the Impact of E × B Drift on the Vertical Distribution of the Plasma Density Over the Geomagnetic Equatorial Ionospheric Region

Ashok,

Ambili,

Choudhary

2024

JGR Space Physics

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Using an in–house developed Quasi Two–Dimensional (QTD) physics–based ionospheric model, the impact of E × B drift velocity on the vertical distribution of the electron density over the equatorial latitude has been investigated. The vertical drift measurements from (a) drift analysis software of Digisonde (b) derived from Digisonde ionograms (c) calculated from the Scherliess–Fejer (SF) model, and (d) obtained from the magnetometer ΔH measurements have been used in this study. Four quiet days in a low solar activity year, representing four seasons of the year 2010, have been chosen for the study. The model–derived electron density profiles using the vertical drifts from all four methods matched well with the Digisonde observation below ∼150 km at all the Local Times (LTs) for all 4 days. However, since the Digisonde–derived drifts were very low, centered mostly around zero, it led to the overestimation/underestimation of the F–region peak plasma density (nmF2)/height (hmF2). The model simulated electron density profiles using the SF model, and ΔH derived vertical drifts showed good agreement with the observation up to an altitude of ∼350 km. The study showed that vertical drift is a factor that controls the nmF2 trough around noon over the equatorial latitude. It is seen that plasma diffusion occurs only beyond an altitude of 350 km, while the range of altitudes between 320 and 350 km acts as the “diffusion threshold height.” This finding has significant implications for understanding plasma dynamics in the equatorial ionosphere.

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Geomagnetic storm time studies using Digisonde data

Scali

Reinisch

1997

Advances in Space Research

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F-region drift velocities in the dusk sector mid-latitude trough

Cited by 3 publications

References 30 publications

Thermosphere and ionosphere response to subauroral polarization streams (SAPS): Model simulations

Thermosphere and ionosphere response to subauroral polarization streams (SAPS): Model simulations

A Numerical Study on the Impact of E × B Drift on the Vertical Distribution of the Plasma Density Over the Geomagnetic Equatorial Ionospheric Region

Geomagnetic storm time studies using Digisonde data

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