Results 141 to 150 of about 614 (179)
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Auroral morphology of the midday oval
Journal of Geophysical Research: Space Physics, 1986Auroral displays in the noon sector were examined by using hundreds of Defense Meteorological Satellite Program auroral images, taken over the southern polar region in austral winters, in order to determine the morphology. The auroral displays in the midday part of the auroral oval can be grouped into five characteristic types, depending on the ...
C.‐I. Meng, R. Lundin
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Expansion and Contraction of the Auroral Oval Area
2023The aurora is a visible manifestation of Earth’s coupling to near-Earth space. The emitted light is produced by charged particles that precipitate into the upper atmosphere. These particles are usually located on closed magnetic field lines that connect directly between the northern and southern hemisphere.
Anders Ohma +7 more
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Weak auroral emissions and particle precipitations in the dusk auroral oval
Journal of Geophysical Research: Space Physics, 1989Faint auroral displays in the low‐latitude region of the duskside auroral oval were examined by using 5577 Å, 6300 Å, and 4861 Å auroral images from three monochromatic all‐sky television cameras at Syowa Station, Antarctica, and simultaneous precipitating auroral particle data obtained by the U.S.
Takayuki Ono +2 more
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1996
The basic structure of the auroral oval was pieced together from relatively local magnetometer measurements and all-sky photographs taken on the ground. The all-sky cameras picked out relatively intense features whose intensities exceeded roughly one kilorayleigh.
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The basic structure of the auroral oval was pieced together from relatively local magnetometer measurements and all-sky photographs taken on the ground. The all-sky cameras picked out relatively intense features whose intensities exceeded roughly one kilorayleigh.
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Open Magnetosphere and the Auroral Oval
1977The impact of a unidirectionally streaming, unmagnetized plasma upon a dipole field was first studied by Chapman and Ferraro in a series of papers in 1931–33. The front of the stream was assumed to be an infinite plane or a cylindrical surface. Later, their study was extended by Zhigulev and Romishevskii (1960), Hurley (1961a, b) and Dungey (1961a) for
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Electric fields in the dayside auroral oval
Journal of Geophysical Research: Space Physics, 1980The results from four independent electric field experiments flown on three Black Brant 4 rockets in the forenoon dayside auroral oval in December 1974 and January 1975 are correlated with ground‐based observations and rocket particle data. The electric field varied from zero to 150 mV/m.
T.S. Jørgensen +9 more
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The oval of auroral hydrogen emissions
Canadian Journal of Physics, 1976Diurnal curves of the average location of the equatorial edge of the auroral hydrogen oval (AHO) are presented for various levels of magnetic activity. Under absolutely quiet conditions this boundary is symmetrical about 23:15 corrected geomagnetic time (CGT), at which time it lies near 69.5° CG latitude.
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Dayside Auroral Dynamics During Reconfiguration of the Auroral Oval
1994This paper presents a case study of the dayside auroral behavior during a rapid expansion of the auroral oval. An unstructured auroral form characterized by a large I(630.0 nm)/ I(557.7 nm) ratio is observed to rapidly drift from the east into the field of view of a set of ground based instruments.
J. I. Minow +3 more
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The continuity of the auroral oval in the afternoon sector
Planetary and Space Science, 1975Abstract United States Air Force DMSP satellite auroral images and South Pole auroral all-sky camera data are presented to provide new direct evidence that the afternoon sector auroras lie within a continuous oval belt. An example is also presented to illustrate that afternoon substorm auroras occur within the auroral oval configuration.
A.L. Snyder, S.-I. Akasofu, D.S. Kimball
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The auroral oval during the substorm development
Planetary and Space Science, 1976The direction of motion of the auroral forms in several sectors of the auroral oval during substorms is studied. The creation phase is characterized by the equatorward displacement of the luminous region in evening (15–21 LT) and in day (09–15 LT) hours, while individual forms in the luminous region drift mainly poleward with a mean velocity of 230 m ...
V.G. Vorobjev +2 more
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