Vertical drift velocities and east-west electric fields at the magnetic equator

Woodman, R. F.

doi:10.1029/ja075i031p06249

Cited by 460 publications

(273 citation statements)

References 9 publications

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“…An important feature of the vertical drift is the sudden enhancement that occurs around 1900 LT and before the vertical drift tums downward. This feature was called the pre reversal enhancement (PRE) by Woodman [1970]. The occurrence of the PRE is important because this additional upward velocity displaces the F layer further upward, favoring the initiation of ESF.…”

Section: Introductionmentioning

confidence: 99%

Measurement of the latitudinal distributions of total electron content during equatorial spread F events

Valladares¹,

Basu²,

Groves³

et al. 2001

J. Geophys. Res.

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Section: Introductionmentioning

confidence: 99%

Measurement of the latitudinal distributions of total electron content during equatorial spread F events

Valladares¹,

Basu²,

Groves³

et al. 2001

J. Geophys. Res.

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“…Our database consists of over 200 evening and nighttime periods from April 1968 to March 1992. The experimental procedure for measuring plasma drifts with the Jicamarca radar was described by Woodman [1970]. These observations were typically made over an altitudinal range of 200-600 km, with an altitudinal resolution of 25-40 km, and with an integration time of-5 min.…”

Section: Measurement Techniques and Datamentioning

confidence: 99%

Effects of the vertical plasma drift velocity on the generation and evolution of equatorial spread F

Fejer¹,

Scherliess²,

Paula³

1999

J. Geophys. Res.

656

754

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Abstract. We use radar observations from the Jicamarca Observatory from 1968 to 1992 to study the effects of the F region vertical plasma drift velocity on the generation and evolution of equatorial spread F. The dependence of these irregularities on season, solar cycle, and magnetic activity can be explained as resulting from the corresponding effects on the evening and nighttime vertical drifts. In the early night sector, the bottomside of the F layer is almost always unstable. The evolution of the unstable layer is controlled by the history of the vertical drift velocity. When the drift velocities are large enough, the necessary seeding mechanisms for the generation of strong spread F always appear to be present. The threshold drift velocity for the generation of strong early night irregularities increases linearly with solar flux. The geomagnetic control on the generation of spread F is season, solar cycle, and longitude dependent. These effects can be explained by the response of the equatorial vertical drift velocities to magnetospheric and ionospheric disturbance dynamo electric fields. The occurrence of early night spread F decreases significantly during equinox solar maximum magnetically disturbed conditions due to disturbance dynamo electric fields which decrease the upward drift velocities near sunset. The generation of late night spread F requires the reversal of the vertical velocity from downward to upward for periods longer than about half an hour. These irregularities occur most often at -0400 local time when the prompt penetration and disturbance dynamo vertical drifts have largest amplitudes. The occurrence of late night spread F is highest near solar minimum and decreases with increasing solar activity probably due to the large increase of the nighttime downward drifts with increasing solar flux.

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“…A unique feature of the low latitude ionosphere is the pre-reversal enhancement (PRE) [e.g., Woodman, 1970], a sharp upward spike in the vertical ion velocities that occurs shortly after local sunset, superimposed on the typical diurnal variation of daytime upward and nighttime downward drifts.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the pre‐reversal enhancement in the low latitude vertical ion drifts

Fesen¹,

Crowley²,

Roble³

et al. 2000

Geophysical Research Letters

181

169

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Vertical drift velocities and east-west electric fields at the magnetic equator

Cited by 460 publications

References 9 publications

Measurement of the latitudinal distributions of total electron content during equatorial spread F events

Measurement of the latitudinal distributions of total electron content during equatorial spread F events

Effects of the vertical plasma drift velocity on the generation and evolution of equatorial spread F

Simulation of the pre‐reversal enhancement in the low latitude vertical ion drifts

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