Observations of an enhanced convection channel in the cusp ionosphere

Journal Article · Mon Mar 01 04:00:00 EST 1993 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/92JA01382· OSTI ID:6873478

Pinnock, M; Rodger, A S; Dudeney, J R ^[1]; Baker, K B; Neweli, P T; Greenwald, R A ^[2]; Greenspan, M E ^[3]

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1. Natural Environment Research Council, Cambridge (United Kingdom)
2. Johns Hopkins Univ., Laurel, MD (United States)
3. Boston Univ., MA (United States)

Transient or patchy magnetic field line merging on the dayside magnetopause, giving rise to flux transfer events (FTEs), is thought to play a significant role in energizing high-latitude ionospheric convection during periods of southward interplanetary magnetic field. Several transient velocity patterns in the cusp ionosphere have been presented as candidate FTE signatures. Instrument limitations, combined with uncertainties about ionospheric signature of FTEs have yet to be presented. This paper describes combined observations by the PACE HF backscatter radar and the DMSP F9 polar-orbiting satellite of a transient velocity signature in the southern hemispheric cusp. The prevailing solar wind conditions suggest that it is the result of enhanced magnetic merging at the magnetopause. The satellite particle precipitation data associated with the transient are typically cusplike in nature. The presence of spatially discrete patches of accelerated ions at the equatorward edge of the cusp is consistent with the ion acceleration that could occur with merging. The combined radar line-of-sight velocity data and the satellite transverse plasma drift data are consistent with a channel of enhanced convection superposed on the ambient cusp plasma flow. This channel is at least 900 km in longitudinal extent but only 100 km wide. It is zonally aligned for most of its extent, except at the western limit where it rotates sharply poleward. Weak return flow is observed outside the channel. These observations are compared with and contrasted to similar events seen by the EISCAT radar and by optical instruments. 30 refs., 2 figs.

• OSTI ID: 6873478
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 98:A3; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
CHARGED PARTICLES
CHARGED-PARTICLE PRECIPITATION
CONVECTION
EARTH ATMOSPHERE
ENERGY TRANSFER
HEAT TRANSFER
INTERPLANETARY MAGNETIC FIELDS
IONOSPHERE
IONS
MAGNETIC FIELDS
MAGNETIC FLUX
MAGNETOPAUSE
MASS TRANSFER
MEASURING INSTRUMENTS
PLANETARY IONOSPHERES
PLASMA
PLASMA DRIFT
POLAR CUSP
RADAR
RANGE FINDERS
SATELLITES
SOLAR ACTIVITY
SOLAR WIND
TRANSIENTS