AMPTE/CCE observations of substorm-associated standing Alfvén waves in the midnight sector
Abstract
Magnetic field and medium energy particle data acquired with the AMPTE/CCE spacecraft have been used to study substorm-associated ULF pulsations occurring in the midnight sector at a radial distance of 8 to 9 RE. The particle data are used not only to identify ion injections but also to detect the electric field of ULF waves. A case study of events observed on 23 May 1985 (day 143) shows that the waves have the properties of a fundamental-mode standing Alfvén wave. The waves started nearly simultaneously with the Pi 2 pulsations observed at the Syowa station (L = 6.1) near midnight local time. However, different frequencies are observed on the ground and in space, which is consistent with the view that the Alfvén waves are excited at the local Alfvén resonance frequency. This CCE observation gives the first unambiguous evidence of substorm-associated standing Alfvén waves in the nightside magnetosphere.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- October 1988
- DOI:
- 10.1029/GL015i011p01287
- Bibcode:
- 1988GeoRL..15.1287T
- Keywords:
-
- Earth Magnetosphere;
- Magnetohydrodynamic Waves;
- Satellite Observation;
- Space Plasmas;
- Standing Waves;
- Ampte (Satellites);
- Geomagnetic Micropulsations;
- Night Sky;
- Magnetospheric Physics: Storms and substorms;
- Magnetospheric Physics: Electric fields;
- Magnetospheric Physics: Magnetosphere-ionosphere interactions;
- Magnetospheric Physics: MHD waves and instabilities