Magnetoplasma diffusion at F2-region altitudes

Kendall, P.C.; Pickering, W. M.

doi:10.1016/0032-0633(67)90118-3

Cited by 68 publications

(32 citation statements)

References 16 publications

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“…In the F2 layer, the velocity ( V ) of E field driven plasma motion, occurring perpendicular (⊥) to the geomagnetic field ( B ) lines, can be estimated as = ( E × B )/ B 2 [ Kendall and Pickering , 1967]. At high latitudes, this estimation models a horizontal plasma motion, which is usually termed “plasma convection.” The horizontal variation of this convection velocity, via the variation of the B field and E field intensities, creates the corresponding variations of the electrodynamic processes, which contribute to the longitudinal variation of the midlatitude trough.…”

Section: Discussionmentioning

confidence: 99%

Investigating the relationships among the South Atlantic Magnetic Anomaly, southern nighttime midlatitude trough, and nighttime Weddell Sea Anomaly during southern summer

Horvath

Lovell

2009

J. Geophys. Res.

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[1] This study utilized the multi-instrument data of the Defense Meteorological Satellite Program to investigate the evening/nighttime topside ionosphere during the 1996/1997 southern summer. A series of regional surface maps were constructed and permitted the tracking of the topside ionosphere's plasma density features, plasma composition, thermal structures, and vertical and horizontal plasma flows. These maps tracked a complete nighttime Weddell Sea Anomaly (WSA) and strong horizontal plasma flows that registered the high-conductivity regions of the South Atlantic Magnetic Anomaly (SAMA). These regions developed over the southeastern Pacific, just equatorward of the WSA, and over the South Atlantic. A heavy-ion stagnation trough developed poleward of the SAMA affected regions. Thus, the trough appeared on the WSA's equatorward side. During periods of increasing magnetic activity, the plasmapause was the WSA's poleward boundary. A statistical study modeled the trough's magnetic activity dependence and revealed a strong east-west hemispherical difference that was due to the SAMA effects. When the AE6 was 0 nT, the trough appeared at (57.49 ± 2.82)°S (geomagnetic) over the southwestern hemisphere. Owing to the SAMA's special electrodynamic effects, the trough developed at lower latitudes, (42.39 ± 3.04)°S, over the southeastern hemisphere. Meanwhile, the plasmapause occurred at $(62.5 ± 4)°S, and the WSA's peak appeared at $(56.2 ± 4)°S. Hence, there was a $20°(lat) separation between the trough and the plasmapause over the southeastern hemisphere. Between 210°E and 330°E (geographic), the WSA filled this gap. With increasing magnetic activity, the trough in the SAMA affected regions moved poleward at a rate of (0.0157 ± 0.004)°S/nT. Elsewhere, it had a (0.0196 ± 0.002)°S/nT equatorward movement.

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Section: Discussionmentioning

confidence: 99%

Investigating the relationships among the South Atlantic Magnetic Anomaly, southern nighttime midlatitude trough, and nighttime Weddell Sea Anomaly during southern summer

Horvath

Lovell

2009

J. Geophys. Res.

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“…This large horizontal circulation produces large‐scale convection patterns, which drive the high‐latitude winds [ Titheridge , 1995]. These east‐west electric fields transport the ionization primarily perpendicular to the magnetic field lines [ Kendall and Pickering , 1967; Anderson , 1976]. For a conventional convection pattern, wherein the dawn‐dusk electric field is situated in the equatorial plane and a stagnation point is at dusk [ Kavanagh et al , 1968], several high‐latitude ionospheric features can be accounted for.…”

Section: Tec Space Weather Observations and Discussionmentioning

confidence: 99%

A total electron content space weather study of the nighttime Weddell Sea Anomaly of 1996/1997 southern summer with TOPEX/Poseidon radar altimetry

Horvath

2006

J. Geophys. Res.

121

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[1] This paper reports on a total electron content space weather study of the nighttime Weddell Sea Anomaly, overlooked by previously published TOPEX/Poseidon climate studies, and of the nighttime ionosphere during the 1996/1997 southern summer. To ascertain the morphology of spatial TEC distribution over the oceans in terms of hourly, geomagnetic, longitudinal and summer-winter variations, the TOPEX TEC, magnetic, and published neutral wind velocity data are utilized. To understand the underlying physical processes, the TEC results are combined with inclination and declination data plus global magnetic field-line maps. To investigate spatial and temporal TEC variations, geographic/magnetic latitudes and local times are computed. As results show, the nighttime Weddell Sea Anomaly is a large ($1,600(°) 2 ; $22 million km 2 estimated for a steady ionosphere) space weather feature. Extending between 200°E and 300°E (geographic), it is an ionization enhancement peaking at 50°S-60°S/250°E-270°E and continuing beyond 66°S. It develops where the spacing between the magnetic field lines is wide/medium, easterly declination is large-medium (20°-50°), and inclination is optimum ($55°S). Its development and hourly variations are closely correlated with wind speed variations. There is a noticeable ($43%) reduction in its average area during the high magnetic activity period investigated. Southern summer nighttime TECs follow closely the variations of declination and field-line configuration and therefore introduce a longitudinal division of four (Indian, western/eastern Pacific, Atlantic). Northern winter nighttime TECs measured over a limited area are rather uniform longitudinally because of the small declination variation. TOPEX maps depict the expected strong asymmetry in TEC distribution about the magnetic dip equator.

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“…However, over the South Atlantic, the total B field intensity is anomalously low ~22.8×10 3 nT from Trivedi et al . [], a phenomenon known as the South Atlantic Magnetic Anomaly (SAMA), that makes the E × B drift unusually strong, because its magnitude is E × B / B 2 [ Kendall and Pickering , ]. Furthermore, there are special electrodynamic effects in the SAMA region that can further increase the magnitude of the E × B drift by increasing the E field.…”

Section: The Spatial‐time Distribution Characteristics Of the Seismo‐mentioning

confidence: 99%

Statistical analysis of an ionospheric parameter as a base for earthquake prediction

Parrot

2013

JGR Space Physics

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[1] This paper is related to the use of ionospheric density variations to tentatively predict earthquakes. The results of this statistical analysis are presented as a function of various parameters. The ion density was recorded by the low-altitude satellite DEMETER during more than 6 years, and a search for anomalies was automatically conducted with the complete data set. In a second time, a software checked if each anomaly could correspond to an earthquake. The search was conducted at less than 1500 km from the anomaly positions, and until 15 days after the anomaly time. The earthquakes have been classified depending on their magnitude, depth, and position (below the sea or inland). This attempt to predict earthquakes of course generates a lot of false alarms and wrong detections. Nevertheless, it is shown that the number of good detections increases with the magnitude of the earthquakes. In average the number of perturbations is higher the day of the earthquake, and then smoothly decreases for the days before. Earthquakes below the sea are better detected. There are seismic areas close to the South Atlantic Magnetic Anomaly and at high latitudes where the number of natural perturbations is too important to expect a high number of good detections. Finally, when there are several perturbations corresponding to a single earthquake, it is possible to combine their positions to have a better estimation of the location of the future epicenter. However, uncertainties about the time and the magnitude are large.Citation: Li, M., and M. Parrot (2013), Statistical analysis of an ionospheric parameter as a base for earthquake prediction,

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Magnetoplasma diffusion at F2-region altitudes

Cited by 68 publications

References 16 publications

Investigating the relationships among the South Atlantic Magnetic Anomaly, southern nighttime midlatitude trough, and nighttime Weddell Sea Anomaly during southern summer

Investigating the relationships among the South Atlantic Magnetic Anomaly, southern nighttime midlatitude trough, and nighttime Weddell Sea Anomaly during southern summer

A total electron content space weather study of the nighttime Weddell Sea Anomaly of 1996/1997 southern summer with TOPEX/Poseidon radar altimetry

Statistical analysis of an ionospheric parameter as a base for earthquake prediction

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