The interpretation of changes in the E- and F1-layers during solar eclipses

Minnis, C. M.

doi:10.1016/0021-9169(58)90058-8

Cited by 15 publications

(4 citation statements)

References 10 publications

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“…The occurrence of a solar eclipse provides the opportunity to study the response of the Earth's ionized atmosphere to large, but short-lived, changes in the solar input. Previous eclipse studies have been used to determine production and recombination rate coefficients in the E and F1 regions [Ratcliffe, 1956;Minnis, 1958;Marriott et al, 1972], while the anomalous electron density behavior near the F2 peak observed during early eclipse studies highlighted the importance of transport effects above these altitudes [Ratcliffe and Weekes, 1960]. Other eclipse studies have been used to map the sources of ionizing radiation on the Sun [Minnis, 1958;Rishbeth, 1968;Horvarth and Theon, 1972;Brace et al, 1972].…”

Section: Introductionmentioning

confidence: 99%

“…Previous eclipse studies have been used to determine production and recombination rate coefficients in the E and F1 regions [Ratcliffe, 1956;Minnis, 1958;Marriott et al, 1972], while the anomalous electron density behavior near the F2 peak observed during early eclipse studies highlighted the importance of transport effects above these altitudes [Ratcliffe and Weekes, 1960]. Other eclipse studies have been used to map the sources of ionizing radiation on the Sun [Minnis, 1958;Rishbeth, 1968;Horvarth and Theon, 1972;Brace et al, 1972]. The response of the ionosphere to eclipses is well documented, and the coupling between the neutral atmosphere and the D, E, and F regions at these periods is also well documented with both experimental [King et al, National Astronomy and Ionosphere Center, Arecibo Observa-1967; Oliver andBowhill, 1974;Salah et al, 1986] and theoretical [Rishbeth, 1968;Stubbe, 1970;Roble et al, 1986] results.…”

Section: Introductionmentioning

confidence: 99%

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Measurements of the topside ionosphere over Arecibo during the total solar eclipse of February 26, 1998

MacPherson¹,

González²,

Sulzer³

et al. 2000

J. Geophys. Res.

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Abstract. The Arecibo incoherent scatter radar facility was operated on February 26, 1998, and was used to observe the total solar eclipse that occurred over the Caribbean. A maximum of 87% obscuration was observed over Arecibo at 1430 LT (1830 UT). The radar was operated using an experimental technique, which uses a 300/•s single/multi-frequency pulse, to gather data from the altitude range 146-2412 km. The Sheffield University plasmasphere ionosphere model was used to interpret the measurements. The electron temperature was found to have decreased by 600 K at 400 km altitude, but the magnitude of the decrease becomes smaller with increasing altitude. This is shown to be the result of the lesser degree of obscuration of the solar disk at latitudes north of Arecibo. Conjugate point photoelectron heating effects are also shown to play a significant role in the electron energy balance during the eclipse. The H + ion temperature exhibited a response to the eclipse, with

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Measurements of the topside ionosphere over Arecibo during the total solar eclipse of February 26, 1998

MacPherson¹,

González²,

Sulzer³

et al. 2000

J. Geophys. Res.

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“…Measurements of the electron density in the E and F• layers made during the time of solar eclipses have provided values for the recombination coefficient at these heights [Ratcli#e, 1956;Minnis, 1958]. Observations at F= region heights have provided contradictory results; sometimes the density has decreased and at other times it has actually increased.…”

Section: Introductionmentioning

confidence: 99%

AnFregion eclipse

Evans¹

1965

J. Geophys. Res.

108

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Observations of the electron density, electron temperature, and ion temperature were made over the height range 240–750 km vertically above Millstone Radar Observatory on July 19–21, 1963. The technique employed for these measurements is the incoherent backscatter method. The eclipse occurred on the afternoon of July 20 and caused a large rapid decrease in the electron temperature at all heights and a subsequent recovery. The ion temperature was seen to change at all heights almost equally rapidly, though by a smaller amount. These changes in temperature caused a rapid reduction in the value for the diffusive equilibrium scale height. As a consequence, ionization moved downward and the density at hmax increased, though at altitudes above 425 km it decreased. The total electron content of the region under study was about 7×1012 electrons/cm3 at the commencement of the event but had declined to about 6×1012 electrons/cm2 by the time point of last contact was reached.

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“…This diurnal hour daylight/darkness cycle has been well studied and understood for several decades, but the short period of darkness (~tens of minutes) during an eclipse provides us with a unique opportunity to study the short‐term dynamics and responses of the ionosphere. Ground‐based observations of the ionospheric response to eclipses have been done since the 1950s (e.g., Minnis, ) and spacecraft observations date back to at least 1980 (West et al, ). More recent spacecraft observations of ionospheric responses to eclipses have been performed by Tomas et al (), Wang et al (), and Maji et al ().…”

Section: Introductionmentioning

confidence: 99%

Topside Ionospheric Electron Temperature Observations of the 21 August 2017 Eclipse by DMSP Spacecraft

Hairston

Mrak

Coley

et al. 2018

Geophysical Research Letters

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During the 21 August 2017 eclipse two separate DMSP spacecraft passed through the lunar penumbra at local afternoon (F16) and near local sunset (F17) in the topside ionosphere at an altitude of ~850 km. Measurements of the in situ electron temperature by the Langmuir probe on each spacecraft showed regions where the temperature decreased on the order of 500 to 1,000 K in the shadow. The patterns of these decreases were sporadic inside the shadow but generally showed the same overall shape in both passes. Comparing these patterns of temperature reductions with the projection of the gradient of the solar EUV radiation in the ionosphere suggests that these complex patterns are a result of the nonuniform distribution of the solar EUV radiation on the Sun at the time of the eclipse.

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The interpretation of changes in the E- and F1-layers during solar eclipses

Cited by 15 publications

References 10 publications

Measurements of the topside ionosphere over Arecibo during the total solar eclipse of February 26, 1998

Measurements of the topside ionosphere over Arecibo during the total solar eclipse of February 26, 1998

AnFregion eclipse

Topside Ionospheric Electron Temperature Observations of the 21 August 2017 Eclipse by DMSP Spacecraft

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