Night-time geomagnetic variations at low latitudes

Stening, R. J.; Winch, D. E.

doi:10.1016/0032-0633(87)90078-x

Cited by 11 publications

(12 citation statements)

References 23 publications

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“…One would expect nighttime amplitudes to be 1/40 daytime values if they follow the conductivity variation. Stening & Winch (1987) also found a possible westward (non-lunar) electrojet at night. Matsushita & Campbell (1972) found a nighttime lunar tide in H at Huancayo leading the daytime tide by only 0-3 hr while we find a phase leading by 5-6 hr.…”

Section: G E N E R a L Discussionmentioning

confidence: 90%

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The lunar geomagnetic tide at night

Stening

Winch

1987

Geophysical Journal International

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Hourly values from 1964-65 of the three geomagnetic elements from a large number of stations have been analysed for the various lunar components. These were combined to examine in detail the seasonal and diurnal variations of the lunar geomagnetic tide at night.Comparison of the values for the oceanic component calculated in a similar way to Malin (1973) showed good agreement between sunspot maximum and minimum years.When seasonal changes were included, the D and Z elements gave evidence of a lunar modulation of magnetic field aligned currents entering the ionosphere in auroral regions. The effects of these currents appeared to extend as far away as the equator. Changes in their amplitude during the night also suggest a relation to auroral processes.There is a just-resolved nighttime equatorial electrojet H component and a quite large lunar H component in the auroral regions.

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Section: G E N E R a L Discussionmentioning

confidence: 90%

“…Hourly values of the geomagnetic elements for the years 1964 and 1965 are analysed using the method of Winch & Cunningham (1972). In each month the five internationally disturbed days ('D days') are omitted from the analysis.…”

Section: R J Steningand D E Winch 2 Analysismentioning

confidence: 99%

The lunar geomagnetic tide at night

Stening

Winch

1987

Geophysical Journal International

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“…Not being of immediate interest, Sastry (1970) did not report the result of the Langmuir probe in his flight 20.08 or RFR59. However, Stening & Winch (1987) used the electron density of this flight in model calculations regarding it as an upper limit on the possible night-time electron density. Their calculation led to a peak E-region current of slightly less than 0.28 A km-2 and a contribution from the F-region of only 1/10 of that from the E-region.…”

Section: Resultsmentioning

confidence: 99%

A study of rocket measurements of ionospheric currents-I. General setting and night-time ionospheric currents

Onwumechili

1992

Geophysical Journal International

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Some 76 results of rocket measurements of ionospheric currents worldwide from 1948 to 1973, have been collected and arranged into seven groups suggested by the characteristics of geomagnetic variations which they cause. Their organization and planned study in five parts are outlined. This first part also presents the study of the group of rocket measurements of night-time ionospheric currents. The finding from nine rocket flight results is that the attempts to detect night-time ionospheric currents with rocket-borne instruments in the low and mid-latitudes have not found distinctly clear indication of such currents. The remnant E-region electron density at night measured aboard two rockets led to calculated currents so small that they support the above finding. Discussion of the rocket and other relevant studies led to the conclusion that nocturnal ionospheric currents d o not seem to exist at any part of the solar cycle.

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“…So the result would be that during June the value measured at Northern (Southern) observatories would be higher (lower) than the expected one. Stening and Winch [1987] has already noted the necessity of these two effects.…”

Section: Analysis and Interpretationmentioning

confidence: 95%

A different interpretation of the annual and semiannual anomalies on the magnetic activity over the Earth

Azpilicueta¹,

Brunini²

2012

J. Geophys. Res.

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The H component of the magnetic field measured at the terrestrial surface presents several periodic signals caused by changes in the ring current that flows within the terrestrial magnetosphere. One of the most important of them is associated to the phenomenon known as the Semiannual Anomaly which produces two significant minima during the equinoxes. This phenomenon is global, i.e., every observatory registers a similar effect independently of the hemisphere where it is located. A second important signal is due to the phenomenon known as the Annual Anomaly that produces significant different values for solstices, with a particular feature: the effect depends on the hemisphere where the observatory is located, with maximum during local summer. In spite of the time since their discoveries (more than a hundred years ago) the physical processes behind them are still open to discussion. In this work we present a new physical interpretation for the combined effects of both anomalies. The main concept developed is that along the year the shape of the magnetospheric cavities within which the ring current flows is deformed according to the geometric configuration between the solar wind and the magnetosphere.

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Night-time geomagnetic variations at low latitudes

Cited by 11 publications

References 23 publications

The lunar geomagnetic tide at night

The lunar geomagnetic tide at night

A study of rocket measurements of ionospheric currents-I. General setting and night-time ionospheric currents

A different interpretation of the annual and semiannual anomalies on the magnetic activity over the Earth

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