Distortion of the E Layer of the Ionosphere by Electrical Currents Flowing in it

Appleton, E.V.; Lyon, A. J.; Turnbull, A. G.

doi:10.1038/176897a0

Cited by 26 publications

(11 citation statements)

References 4 publications

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“…The total or integrated conductivity k, which appeared to increase with sunspot number, such that k = 0.012 + 3.1 X 10~5 ic, will probably be affected by the electrostatic field E y . Appleton [Appleton and Lyon, 1957;Appleton, 1955] has shown that the flow of current in the E region is accompanied at times by a lifting of the E region, in good accord with expectations based upon likely directions of the electric field driving the S q currents. Since the mobilities of ions and electrons are height sensitive, the field E y described above will also affect k to some degree.…”

supporting

confidence: 70%

“…The height of the current layer responsible for the solar daily magnetic variation seems measured to be near and within the E region of the ionosphere, as noted by a magnetometer aboard a rocket [Singer, Maple, and Bowen, 1951]. Similar indica tions are shown also by height and ion-density measurements of the E region [ Appleton and Lyon, 1957;Appleton, 1955]. There now appears little doubt that the magnetic daily variations are due to the dynamo action of winds, in which emfs are produced by the motion of electrically con ducting air across the geomagnetic field.…”

mentioning

confidence: 54%

“…The dynamo electric field responsible for the magnetic diurnal variation is probably the result of a daily distortion of the existing zonal wind patterns. This electric field may lift or lower the E region slightly, as Appleton [1955;also Appleton and Lyon, 1957] has shown, thus affecting the integrated effective conductivity of the region carrying S q currents; this change in effective conductivity is evidently small on the average, since the average Jtfi changes nearly linearly with the amplitude of S v…”

Section: The Observed Average Day-to-day Change In Tk Critical Frequementioning

confidence: 99%

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Seasonal changes in day‐to‐day variability of upper air winds near the 100‐km level of the atmosphere

Vestine

1958

Eos Trans. AGU

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The dynamo theory of the magnetic daily variation predicts that winds flowing within the E region at a height of roughly 100 km generate a world‐wide electric current system at this level. The electric currents are generated mainly in middle and high latitudes by the horizontal motion of electrically conducting air across the radial component of the geomagnetic field. Near the equator the geomagnetic field is horizontal so that according to the theory the current above the equator must result from an electrostatic field directed from west to east and overhead near noon, closing the current circuit. The theory also implies that this horizontal electric field must extend to the highly rarefied F region, which will be lifted bodily upwards in response to the crossed electric and magnetic field. Hence day‐to‐day differences in middle latitude winds may be reflected, according to the theory, in day‐to‐day differences, in heights, and hence in ion‐densities of the F region, measured by radio methods. The day‐to‐day differences in ionospheric F region critical frequencies near noon are studied as a measure of corresponding differences in the wind‐generated ionospheric electric field at the magnetic equator. These changes in F region critical frequencies reflect corresponding changes in height of the F region, caused by the electric field of the daily variation. It is shown that the daily variation, though proportional to both the electric field and the electric conductivity, is probably a good indicator of day‐to‐day changes in wind speeds in the E region. The data do not support the view that the ionizing solar radiation fluctuates much from one day to the next. This is in accord also with statistical results obtained by Forbush for solar flares and their effects upon the daily variation. The day‐to‐day changes in wind speed indicated for the E region in middle latitudes are found to be largest in northern winter, and least in northern summer, and are discussed in relation to evidences of variability dependent on season noted from meteorology for tropospheric winds. Changes in wind speed with sunspot cycle are also discussed. The average magnitude of the daily magnetic variation shows a high correlation with sunspots (as high as 0.99 for yearly averages). Thus, having eliminated electric conductivity of the E region as an important cause of the day‐to‐day variability in the magnetic variation, the wind speed in the E region must be able to change by a factor of two or more from one day to the next, as a consequence of solar events.

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supporting

confidence: 70%

mentioning

confidence: 54%

Section: The Observed Average Day-to-day Change In Tk Critical Frequementioning

confidence: 99%

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Seasonal changes in day‐to‐day variability of upper air winds near the 100‐km level of the atmosphere

Vestine

1958

Eos Trans. AGU

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“…An account of the early radio investigations and of the general features of the ionosphere is to be found in the books of Mitra (1952) and Rawer (1953). A short review of the results of routine E-layer measurements has been published by Appleton (1955). More general information about the properties of the upper atmosphere may be found in the reviews by Bates (1949) and Weekes (1954).…”

mentioning

confidence: 99%

Experimental investigations of the ionospheric E-layer

Robinson¹

1959

Rep. Prog. Phys.

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“…Clear evidence of the correlation between small deviations from Chapmanlike behavior of the E region and the upper atmospheric Sq currents was given first by Appleton et al [1955a] and later by Appleton et al [1955b],AppletonandLyon [1955,1961], Brown [1956, 1959], Shimazaki [1958], and Brown et al [1962]. Most of these workers were concerned mainly with the perturbations in the peak height (h•) and peak density (Nm) of the E region over mid-latitude stations.…”

Section: Introductionmentioning

confidence: 92%

Phase height variations and vertical drift in the E region

Bhar¹,

Purkait²

1978

J. Geophys. Res.

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An attempt has been made to explain the departure of the observed hourly variation of phase height of E region reflections at 2.2 MHz from that expected of a simple undisturbed Chapman layer as the effect of vertical electromagnetic drift. Calculations show that a peak drift velocity ranging between the extreme limits 50.0 and 2.5 m/s located about 2 km below the electron density peak may account for the observed departure. Considering some related observational data it is suggested that the vertical drift velocity would be around 10–20 m/s, which is consistent with a value of α in the vicinity of 2–8 × 10−8 cm3/s.

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Distortion of the E Layer of the Ionosphere by Electrical Currents Flowing in it

Cited by 26 publications

References 4 publications

Seasonal changes in day‐to‐day variability of upper air winds near the 100‐km level of the atmosphere

Seasonal changes in day‐to‐day variability of upper air winds near the 100‐km level of the atmosphere

Experimental investigations of the ionospheric E-layer

Phase height variations and vertical drift in the E region

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