Response of the dayside aurora to sharp northward and southward transitions of the interplanetary magnetic field and to magnetospheric substorms

Journal Article · Fri Jul 01 00:00:00 EDT 1977 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA082i019p02723· OSTI ID:7219675

Horwitz, J L; Akasofu, S

Latitudinal shifts of the discrete dayside aurora are examined with respect to variations in the interplanetary magnetic field (IMF) and to magnetospheric substorms. Within 10--15 min after steplike southward (northward) transitions in the IMF the dayside auroral oval moves equatorward (poleward). In at least some cases the auroral shift is similar to an exponential relaxation in latitude from an initial to a final steady state value; for these cases the average exponential time constant is estimated to be 17 min. Substorm features in the dayside aurora include (1) an equatorward shift by 1degree--3degree of the equatorward discrete auroral boundary, (2) a brightening of the discrete aurora near substorm onset, (3) the formation of multiple auroral bands, and (4) poleward motion of short-lived individual auroral ares occurring nearly coincident in time with the equatorward boundary shifts, the average poleward velocity of these ares being approximately 800 m/s.

• Research Organization: Space Sciences Laboratory ES53, Marshall Space Flight Center, Huntsville, Alabama 35812
• OSTI ID: 7219675
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 82:19; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
640203 -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
AURORAL OVAL
EARTH ATMOSPHERE
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC BAYS
MAGNETIC FIELDS
MAGNETOPAUSE
MAGNETOSPHERE
MOTION