Electrical coupling of the E- and F-regions and its effect on F-region drifts and winds

Heelis, R. A.; Kendall, P.C.; Moffett, R. J.; Windle, D.W.; Rishbeth, H.

doi:10.1016/0032-0633(74)90144-5

Cited by 326 publications

(237 citation statements)

References 24 publications

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“…Further, near the magnetic equator, under normal conditions, the neutral wind dynamo also develops enhanced zonal electric field across the terminator because of the conductivity gradient as has been observed and modeled by several authors [Heelis et al, 1974;Farley et al, 1986;Fejer et al, 1979Fejer et al, , 2005. As such, at dusk, the eastward penetration electric field may add to the eastward electric field because of the neutral wind dynamo.…”

Section: Introductionmentioning

confidence: 62%

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

et al. 2007

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different aspects of which have been widely studied by the community. We present here a very complete set of space and ground-based diagnostics that provide the vertical and latitudinal structures of the ionosphere within the South Atlantic magnetic anomaly (SAMA) region and the contiguous parts of South America and Africa. We show that for both storms, the dusk sector corresponding to the universal time (UT) interval between the fast decrease of the SYM-H index and minimum SYM-H value determines uniquely the longitude interval populated by equatorial plasma bubbles and depletions. Further, we find that the UT of these storms is such that the ionospheric density perturbations occur in the SAMA region, which are most extended in latitude and altitude compared with other regions of the globe. In the dusk sector, the eastward penetration electric field, associated with rapid SYM-H decrease, adds to the postsunset eastward E-field because of the F region dynamo, which may be specially enhanced in this longitude interval because of the increased zonal conductivity gradient caused by energetic particle precipitation. This enhanced E-field at dusk causes a rapid uplift of the ionosphere and sets off plasma instabilities to form bubbles or bite-outs. The decreased ion density seen in the Defense Meteorological Satellite Program (DMSP) in situ data at 840 km indicates that the ionospheric plasma has been lifted above the DMSP altitude and transported away from the region by diffusion along magnetic field lines. Plasma bubbles and bite-outs impact satellite communication and navigation systems by introducing scintillations and steep density gradients. This paper corroborates that intense magnetic storms follow the framework, developed by Su. Basu et al. (2001) for moderate storms, that specifies the longitude interval in which such disturbances are most likely to occur.

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Section: Introductionmentioning

confidence: 62%

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

et al. 2007

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“…The stratification of the F 2 layer on the days of occurrence started around 0800 LT and occasionally extended as late as 1600 LT [Balan et al, 1998;Rama Rao et al, 2005]. However, there is usually an evening PRE of the eastward electric field in the dusk sector which occurs simultaneously in the equatorial E and F regions [Heelis et al, 1974]. This upward E × B drift raises the ionization peak and plasma converges in the topside ionosphere and then forms the F 3 layer which could be detected by ground-based ionosondes for a short period when its peak density is greater than that of the F 2 layer.…”

Section: Features Of the Sunset F 3 Layer At Jicamarcamentioning

confidence: 99%

Features of theF₃layer in the low-latitude ionosphere at sunset

et al. 2011

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“…Neutral tidal winds create the E region dynamo field that maps along equipotential field lines to the F region. The F region dynamo field is largely shorted through the E region during the day but becomes more important in the evening as the E region conductivity declines (e.g., Heelis et al, 1974;Heelis, 2004). The basic characteristics of zonal plasma drift at the equator have been presented by Fejer et al (1981Fejer et al ( , 1985 and Fejer (2011) using Jicamarca data.…”

Section: Introductionmentioning

confidence: 99%

“…The daytime east-west F region drifts are representative of the E region neutral winds that generate the vertical electric fields in the equatorial F region (Woodman, 1972). At night the coupling between the E and F regions decreases, and the nighttime zonal drifts become more nearly equal to the F region neutral winds that generate these fields (Woodman, 1972;Heelis et al, 1974). The local time variation of the east-west drifts has been examined by Maynard et al (1988), Coley and Heelis (1989), and Coley et al (1994) using DE 2 satellite measurements of the electric field during a high solar flux period.…”

Section: Introductionmentioning

confidence: 99%

Topside equatorial zonal ion velocities measured by C/NOFS during rising solar activity

et al. 2014

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Abstract. The Ion Velocity Meter (IVM), a part of the Coupled Ion Neutral Dynamic Investigation (CINDI) instrument package on the Communication/Navigation Outage Forecast System (C/NOFS) spacecraft, has made over 5 yr of in situ measurements of plasma temperatures, composition, densities, and velocities in the 400-850 km altitude range of the equatorial ionosphere. These measured ion velocities are then transformed into a coordinate system with components parallel and perpendicular to the geomagnetic field allowing us to examine the zonal (horizontal and perpendicular to the geomagnetic field) component of plasma motion over the 2009-2012 interval. The general pattern of local time variation of the equatorial zonal ion velocity is well established as westward during the day and eastward during the night, with the larger nighttime velocities leading to a net ionospheric superrotation. Since the C/NOFS launch in April 2008, F10.7 cm radio fluxes have gradually increased from around 70 sfu to levels in the 130-150 sfu range. The comprehensive coverage of C/NOFS over the low-latitude ionosphere allows us to examine variations of the topside zonal ion velocity over a wide level of solar activity as well as the dependence of the zonal velocity on apex altitude (magnetic latitude), longitude, and solar local time. It was found that the zonal ion drifts show longitude dependence with the largest net eastward values in the American sector. The pre-midnight zonal drifts show definite solar activity (F10.7) dependence. The daytime drifts have a lower dependence on F10.7. The apex altitude (magnetic latitude) variations indicate a more westerly flow at higher altitudes. There is often a net topside subrotation at low F10.7 levels, perhaps indicative of a suppressed F region dynamo due to low field line-integrated conductivity and a low F region altitude at solar minimum.

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Electrical coupling of the E- and F-regions and its effect on F-region drifts and winds

Cited by 326 publications

References 24 publications

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

Features of theF₃layer in the low-latitude ionosphere at sunset

Topside equatorial zonal ion velocities measured by C/NOFS during rising solar activity

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Electrical coupling of the E- and F-regions and its effect on F-region drifts and winds

Cited by 326 publications

References 24 publications

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

Response of the equatorial ionosphere at dusk to penetration electric fields during intense magnetic storms

Features of theF3layer in the low-latitude ionosphere at sunset

Topside equatorial zonal ion velocities measured by C/NOFS during rising solar activity

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Features of theF₃layer in the low-latitude ionosphere at sunset