Auroral bright spots on the dayside oval

Journal Article · Mon May 01 04:00:00 EDT 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA05p05515· OSTI ID:5831269

Lui, A T.Y. ^[1]; Venkatesan, D; Murphree, J S ^[2]

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1. Johns Hopkins Univ., Laurel, MD (USA)
2. Univ. of Calgary, Alberta (Canada)

Global auroral images from the ultraviolet imager on the Viking spacecraft are used to investigate spatially periodic bright spots on the dayside auroral oval that resemble beads on a string. The newly achieved temporal resolution of 1 min. or less in monitoring worldwide auroral distributions by the Viking imager contributes significant to the capability of observing this phenomenon. It is found that these are frequently seen in the 1,400-1,600 MLT sector. The series of bright spots are not, however, limited to this unique local time sector, since they are seen to extend into the prenoon sector on some occasions. They occur often during substorm intervals but are also seen unaccompanied by substorm activities in the nightside. There is neither a consistent north-south nor east-west direction of motion for all the dayside bright spots observed so far. The observation of the time scales for the transient intensifications of bright spots and the lack of consistent directions of their motion are consistent with the characteristics expected from the suggestion that these bright spots are related to the Kelvin-Helmholtz instability occurring within the magnetosphere.

• OSTI ID: 5831269
• Journal Information: Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 94:A5; ISSN JGREA; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
AURORAL OVAL
BRIGHTNESS
DATA ANALYSIS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTROMAGNETIC RADIATION
ELECTRON DENSITY
F REGION
HELMHOLTZ INSTABILITY
IMAGES
INSTABILITY
IONOSPHERE
LUMINOSITY
MAGNETIC BAYS
MORPHOLOGY
MOTION
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLANETARY IONOSPHERES
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
RADIATIONS
ULTRAVIOLET RADIATION