Near-earth substorm onset: A coordinated study

Journal Article · Mon Aug 15 04:00:00 EDT 1994 · Geophysical Research Letters

DOI:https://doi.org/10.1029/94GL01426· OSTI ID:28552

Persson, M A.L.; Opgenoorth, H J; Eriksson, A I; Dovner, P O ^[1]; Pulkkinen, T I ^[2]; Reeves, G D; Belian, R D ^[3]; Andre, M ^[4]; Blomberg, L G ^[5]; Erlandson, R E ^[6]

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1. Swedish Institute of Space Physics, Uppsala (Sweden)
2. Finnish Meteorological Institute, Helsinki (Finland)
3. Los Alamos National Lab., NM (United States)
4. Swedish Institute of Space Physics, Umea (Sweden)
5. Royal Institute of Technology, Stockholm (Sweden)
6. Johns Hopkins Univ., Laurel, MD (United States); and others

The authors present simultaneous satellite and ground-based measurements of a substorm. Throughout the initial substorm expansion, southward drifting arcs are observed poleward of the expanding substorm aurora, indicating two independent systems of particle precipitation. Freja passes the brightening onset arc in the topside ionosphere near the moment of the substorm onset, observing an Alfven wave, field aligned current and oxygen ion outflow. The substorm onset occurs at low magnetospheric L-shells, near the poleward edge of the region of trapped particles. The location and time for the substorm injection are confirmed by geostationary spacecraft together with magnetometers, all-sky cameras and radar on the ground. The authors believe that the substorm onset may be triggered by modification of the oxygen content of the inner magnetosphere during the growth-phase caused by ionospheric ion outflow. 15 refs., 7 figs.

• OSTI ID: 28552
• Journal Information: Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 17 Vol. 21; ISSN GPRLAJ; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ALFVEN WAVES
CAMERAS
COMPARATIVE EVALUATIONS
ELECTRIC CURRENTS
MAGNETIC BAYS
OXYGEN IONS
RADAR
REMOTE SENSING
START-UP