Correlated observations of the boundary between polar cap and nightside auroral zone by HF radars and the DMSP satellite

Journal Article · Tue Feb 01 00:00:00 EST 1994 · Geophysical Research Letters (American Geophysical Union); (United States)

DOI:https://doi.org/10.1029/93GL02425· OSTI ID:7233508

Senior, C; Cerisier, J C ^[1]; Hanuise, C ^[2]; Villain, J P ^[3]; Greenwald, R G; Newell, P T ^[4]; Rich, F J ^[5]

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1. CRPE/CNRS, Saint-Maur-des-Fosses (France)
2. Universite de Toulon et du Var (France)
3. LPCE, Orleans La Source (France)
4. John Hopkins Univ., Laurel, MD (United States)
5. GMG, Bedford, MA (United States)

Simultaneous observations from HF radars and the DMSP satellite have been used to relate the ionospheric convection pattern and the nightside precipitation at the polar cap-auroral zone boundary. The convection is eastward in the poleward part of the radars field of view and predominantly westward at lower latitudes. The DMSP-F9 particle spectrograms exhibit energetic precipitating protons at the poleward edge of an inverted V'. The downward H[sup +] flow displays spatial filtering effects with a clear energy-latitude dispersion. Single-particle trajectory simulations in appropriate field models demonstrate that these ions were ejected from the neutral sheet near 120 R[sub E] geocentric distance. Most notably, the simulations reveal significant azimuthal dispersion during transport, and the source region in the magnetotail is found to extend over several Earth radii in the dawn-dusk direction, less energetic particles originating duskward of the high-energy ones. The longitudinal spread of the tail source suggests particle precipitation in the ionosphere over at least one hour magnetic local time. Also, as the downflowing protons travel near the lobeward edge of the plasma sheet, the observations suggest that the convection reversal lies inside the boundary layer plasma sheet (PSBL). 11 refs., 3 figs.

• OSTI ID: 7233508
• Journal Information: Geophysical Research Letters (American Geophysical Union); (United States), Vol. 21:3; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOUNDARY LAYERS
CHARGED-PARTICLE PRECIPITATION
IONOSPHERE
CONVECTION
POLAR-CAP AURORAE
AURORAE
EARTH ATMOSPHERE
ENERGY TRANSFER
HEAT TRANSFER
LAYERS
MASS TRANSFER
PLANETARY IONOSPHERES
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)