Transpolar auroras, their particle precipitation, and IMF B sub y component

Journal Article · Thu Aug 01 04:00:00 EDT 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JA02323· OSTI ID:5255838

Makita, K ^[1]; Meng, C I ^[2]; Akasofu, S I ^[3]

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1. Takushoku Univ., Tokyo (Japan)
2. Johns Hopkins Univ., Laurel, MD (United States)
3. Univ. of Alaska, Fairbanks (United States)

Transpolar auroras, their associated particle precipitation, and their occurrence with respect to the IMF B{sub y} polarity are examined on the basis of DMSP F6 auroral images and the corresponding particle data. It is found that the transpolar arcs are located in the poleward edge of the soft particle precipitation region extending from either the dawn or dusk part of the auroral oval precipitation; they are not embedded in the polar rain region. This finding suggests that the transpolar arcs are located along the poleward boundary of the closed field line region (or the equatorward boundary of the open region) as suggested by Meng. Further, the appearance of the extended precipitation region from the oval depends on the polarity of the IMF B{sub y}, in the northern hemisphere morning sector for IMF B{sub y} < 0 or in the evening sector for IMF B{sub y} > 0. In general, the precipitating particle flux in the extended precipitation region is not high enough to produce appreciable luminosity. Thus only the transpolar arcs (associated with relatively intense precipitation) near the poleward boundary tend to become much more luminous, forming the so-called theta aurora.

• OSTI ID: 5255838
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:A8; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
&amp; Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
AURORAL OVAL
CHARGED-PARTICLE PRECIPITATION
CORRELATIONS
CURRENTS
ELECTRIC CURRENTS
EVALUATION
IMAGES
INTERPLANETARY MAGNETIC FIELDS
LUMINOSITY
MAGNETIC BAYS
MAGNETIC FIELDS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
POLAR-CAP AURORAE
SATELLITES