Vertical motions of the midlatitude<i>F</i><sub>2</sub>layer during magnetospheric substorms

Park, C. G.; Meng, C.‐I.

doi:10.1029/ja076i034p08326

Cited by 25 publications

(6 citation statements)

References 28 publications

(12 reference statements)

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“…The source of this electric field perturbation is not clear. Park [1971] and Meng [1971, 1973] have suggested that nighttime F layer descents may be due to electric fields associated with substorm activity, although this suggestion is not supported by the present level of refinement of theoretical calculations such as those by Jaggi and Wolf[ 1973]. We find no simple correlation between the timing of the few simultaneous descents we have observed and the published values of the auroral electrojet magnetic index.…”

Section: North-to-south Enhancementscontrasting

confidence: 78%

Nighttime dynamics of the F region near Arecibo as mapped by airglow features

Sobral

Carlson

Farley³

et al. 1978

J. Geophys. Res.

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Red line (6300 Å) airglow measurements have been made at Arecibo (29°N geomagnetic latitude) by using a scanning photometer in order to determine the direction and phase velocity of propagation of major airglow enhancements, which incoherent scatter and ionosonde measurements have shown are in turn associated with pronounced descents of the F region. The scans were made in the N‐S direction on 13 nights and in the E‐W direction on five nights. The most common type of descent is observed first to the south and then progresses northward, with an apparent phase velocity of the order of 300 m/s. Neutral winds are apparently the cause of this type of descent, and future models of upper atmospheric diurnal pressure patterns should be consistent with this large‐scale regular nighttime feature. Descents of the equatorial ionosphere were observed from ionogram data to occur 2–3 hours earlier than this type of airglow enhancement at Arecibo. The equatorial descents are caused by electric fields and do not directly drive the descent at Arecibo, but both are ultimately driven by the global neutral pressure gradients and resulting winds. A second type of enhancement, seen on occasion and probably due to traveling ionospheric disturbances, was observed to travel from north to south with comparable velocities. A third type does not seem to correspond to anything previously reported in the literature. Sudden descents lasting an hour or so sometimes occurred nearly simultaneously over regions extending at least 1000 km in the N‐S or E‐W direction.

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Section: North-to-south Enhancementscontrasting

confidence: 78%

Nighttime dynamics of the F region near Arecibo as mapped by airglow features

Sobral

Carlson

Farley³

et al. 1978

J. Geophys. Res.

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“…Ionospheric effects of substorm electric fields are only beginning to be investigated. Park and Meng [1971] have shown winter hemisphere evidence of lowering and raising of the F layer, apparently in association with substorm electric fields, and Park [1971] has discussed the accompanying changes in the critical frequency and columnar content. Sudden changes in neutral-air winds can also cause vertical motions of the F layer, and experimental results at lower latitudes have been interpreted in terms of neutral winds [Behnke, 1970;Herper, 1971;Wright, 1971].…”

Section: Substorm Electric Fields Appear To Cause Large-scale Distortmentioning

confidence: 99%

On what ionospheric workers should know about the plasmapause‐plasmasphere

Carpenter¹,

Park²

1973

Reviews of Geophysics

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287

130

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Recent research on the structure and dynamics of the magnetospheric thermal plasma indicates that the vast region above an altitude of ∼1000 km rivals the underlying ionosphere in complexity and that it is coupled to the lower region in complicated, physically important ways. An example involves the relation of the electron content of magnetospheric tubes of ionization to the electron content of the regular ionosphere. Tube volume between ∼1000 km and the magnetic equator varies rapidly over a relatively small range of tube end point latitudes, which gives rise to correspondingly rapid variations with latitude in coupled effects that involve interchange of ionization between the upper and lower regions. In the past, some correlative studies involving the plasmapause have been hindered by lack of information concerning (1) the unsteady nature of the process by which the disturbed‐time plasmapause profile is established and (2) the fact that at most times and at most locations the plasmasphere‐plasmapause system is in a state of recovery. A series of equatorial density profiles is shown to illustrate the reduction of plasmapause radius during brief periods of increased disturbance and the recovery of the plasmasphere by various processes, particularly by filling from the underlying ionosphere. A number of research results are presented as part of a ‘quick‐reference guide’ to the plasmasphere. To the ionospheric observer, the plasmapause should appear to have a complex but generally predictable geometry as well as characteristic motions. A crude predictor of plasmapause L value (Lpp) in the post‐midnight period as a function of magnetic disturbance is the formula Lpp = 5.7‐0.47Kp, where Kp is the maximum 3‐hour Kp value in the preceding 12 hours. A ground station at L ∼ 3.7 is recommended as optimum for observation of plasmapause‐associated effects directly overhead. The plasmasphere is regularly perturbed by substorm‐associated convection electric fields, and these apparently have important effects on the nightside ionosphere at middle latitudes. Other known departures of the plasmasphere from corotation are expected to have their counterparts in the ionosphere.

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“…Therefore it is not surprising that numerous attempts have been made to estimate the electric field intensity in the middle-latitudinal ionosphere by means of indirect methods. One of those methods is based on the investigation of the variations of the F2-1ayer parameters during auroral substorms (Park and Meng, 1971). However the behaviour of the F2-1ayer is not yet quite clear, because the interpretation of the data obtained by this method seems unclear.…”

Section: Electric Fields At Low and Middle Latitudesmentioning

confidence: 99%

Electric fields and currents in the ionosphere

Pudovkin

1974

Space Sci Rev

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In this paper some theories and experimental data on the electric fields and currents in the ionosphere are reviewed. Electric fields originating in the polarization of the ionosphere as well as in local irregularities are considered. Special attention is paid to field-aligned currents as a regulator of the intensity and configuration of the ionospheric polarization field, the anomalous resistivity being one of the most important characteristics of the magnetospheric plasma. Present-day models of the magnetosphere and corresponding electric field generation mechanisms are discussed. Various models of the DP1 current system are considered and the main characteristics that allow us to distinguish between them are listed. Experimental data on the ionospheric electric field are considered; a modified model of Silsbee and Vestine is shown to fit these data reasonably well.

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Vertical motions of the midlatitudeF₂layer during magnetospheric substorms

Cited by 25 publications

References 28 publications

Nighttime dynamics of the F region near Arecibo as mapped by airglow features

Nighttime dynamics of the F region near Arecibo as mapped by airglow features

On what ionospheric workers should know about the plasmapause‐plasmasphere

Electric fields and currents in the ionosphere

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Vertical motions of the midlatitudeF2layer during magnetospheric substorms

Cited by 25 publications

References 28 publications

Nighttime dynamics of the F region near Arecibo as mapped by airglow features

Nighttime dynamics of the F region near Arecibo as mapped by airglow features

On what ionospheric workers should know about the plasmapause‐plasmasphere

Electric fields and currents in the ionosphere

Contact Info

Product

Resources

About

Vertical motions of the midlatitudeF₂layer during magnetospheric substorms