Aurora and airglow intensity variations with time and magnetic activity at southern high latitudes

Sandford, B. P.

doi:10.1016/0021-9169(64)90162-x

Cited by 101 publications

(22 citation statements)

References 14 publications

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“…The existence of a region of diffuse subvisual luminosity equatorward of the auroral oval in the nighttime sector was deduced from ground-based observations (Reid and Rees, 1961;Galperin, 1963;Sandford, 1964Sandford, , 1968Eather, 1967;Wiens and Vallance, 1969;Evlashin, 1971 (Alekseev et al, 1975). Detailed morphological studies of diffuse auroras were done based on ISIS-2 satellite observations Lui et al, , 1975Lui et al, , 1977.…”

Section: Nighttime Diffuse Luminosity Equatorward Of the Auroral Ovalmentioning

confidence: 99%

Investigations of the auroral luminosity distribution and the dynamics of discrete auroral forms in a historical retrospective

Feldstein

Vorobjev

Zverev

et al. 2014

Hist. Geo Space. Sci.

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Section: Nighttime Diffuse Luminosity Equatorward Of the Auroral Ovalmentioning

confidence: 99%

Investigations of the auroral luminosity distribution and the dynamics of discrete auroral forms in a historical retrospective

Feldstein

Vorobjev

Zverev

et al. 2014

Hist. Geo Space. Sci.

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“…Sandford (1964) has distinguished two distinct types of auroral forms, the mantle aurora and discrete aurora in photometric studies of southern hemisphere auroral zone displays, and using a local magnetic activity index has produced probability contours based upon two hour data samples (Sandford, 1968). Stringer and Belon (1967) produced probability contours based on auroral occurrences in r quarter hour intervals which provide reasonably complete noontime coverage, and distinguished between types of auroral forms and magnetic activity.…”

Section: Comparison With Optical Measurementsmentioning

confidence: 99%

Primary electron influx to dayside auroral oval

Hoffman¹,

Berko²

1971

J. Geophys. Res.

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Data from the Ogo 4 auroral particles experiment were analyzed to determine properties of the higher latitude region of electron precipitation in the dayside hemisphere. From 7 months of data a probability map of occurrence of this structured low‐energy precipitation was compiled. The highest probabilities are concentrated predominantly between 0500 and 1400 hours magnetic local time, and from 75° to 82½° invariant latitude. There is excellent congruity of these high probabilities of occurrence and the high probability of occurrence of discrete auroral optical emissions, which define the auroral oval in these hours. The soft energy spectrums measured and the estimated total energy influx during typical precipitation events are appropriate for producing the type of aurora observed in these hours. It is concluded that the structured low‐energy electron precipitation is the primary energy source for the dayside auroral oval.

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“…The excitation can be largely caused by the elevation of the ionospheric electron temperature such that the electrons on the hot tail of the thermal ionospheric gas are very efficient in exciting the 1 D 2 state (Wickwar and Kofman, 1984;Lockwood et al, 1993a;Davis and Lockwood, 1996). A region of dominant red-line emission was first reported by Sandford (1964). This was shown to be poleward of the more energetic dayside auroral precipitation by Eather and Mende (1971).…”

Section: Introductionmentioning

confidence: 99%

Coordinated ground-based, low altitude satellite and Cluster observations on global and local scales during a transient post-noon sector excursion of the magnetospheric cusp

et al. 2001

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Abstract. On 14 January 2001, the four Cluster spacecraft passed through the northern magnetospheric mantle in close conjunction to the EISCAT Svalbard Radar (ESR) and approached the post-noon dayside magnetopause over Greenland between 13:00 and 14:00 UT. During that interval, aCorrespondence to: H. J. Opgenoorth (opg@irfu.se) sudden reorganisation of the high-latitude dayside convection pattern accurred after 13:20 UT, most likely caused by a direction change of the Solar wind magnetic field. The result was an eastward and poleward directed flow-channel, as monitored by the SuperDARN radar network and also by arrays of ground-based magnetometers in Canada, Greenland and Scandinavia. After an initial eastward and later 1368 H. J. Opgenoorth et al.: Cluster and ground-based observations of a transient cusp event poleward expansion of the flow-channel between 13:20 and 13:40 UT, the four Cluster spacecraft, and the field line footprints covered by the eastward looking scan cycle of the Söndre Strömfjord incoherent scatter radar were engulfed by cusp-like precipitation with transient magnetic and electric field signatures. In addition, the EISCAT Svalbard Radar detected strong transient effects of the convection reorganisation, a poleward moving precipitation, and a fast ion flowchannel in association with the auroral structures that suddenly formed to the west and north of the radar. From a detailed analysis of the coordinated Cluster and ground-based data, it was found that this extraordinary transient convection pattern, indeed, had moved the cusp precipitation from its former pre-noon position into the late post-noon sector, allowing for the first and quite unexpected encounter of the cusp by the Cluster spacecraft. Our findings illustrate the large amplitude of cusp dynamics even in response to moderate solar wind forcing. The global ground-based data proves to be an invaluable tool to monitor the dynamics and width of the affected magnetospheric regions.

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Aurora and airglow intensity variations with time and magnetic activity at southern high latitudes

Cited by 101 publications

References 14 publications

Investigations of the auroral luminosity distribution and the dynamics of discrete auroral forms in a historical retrospective

Investigations of the auroral luminosity distribution and the dynamics of discrete auroral forms in a historical retrospective

Primary electron influx to dayside auroral oval

Coordinated ground-based, low altitude satellite and Cluster observations on global and local scales during a transient post-noon sector excursion of the magnetospheric cusp

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