Magnetospheric lion roars
The Equator-S magnetometer is very sensitive and has a sampling rate normally of 128 Hz. The high sampling rate for the first time allows detection of ELF waves between the ion cyclotron and the lower hybrid frequencies in the equatorial dawnside magnetosphere. The characteristics of these waves...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2000-04-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/18/406/2000/angeo-18-406-2000.pdf |
| Summary: | The Equator-S magnetometer is very sensitive
and has a sampling rate normally of 128 Hz. The high sampling rate for the first
time allows detection of ELF waves between the ion cyclotron and the lower
hybrid frequencies in the equatorial dawnside magnetosphere. The characteristics
of these waves are virtually identical to the lion roars typically seen at the
bottom of the magnetic troughs of magnetosheath mirror waves. The magnetospheric
lion roars are near-monochromatic packets of electron whistler waves lasting for
a few wave cycles only, typically 0.2 s. They are right-hand circularly
polarized waves with typical amplitudes of 0.5 nT at around one tenth of the
electron gyrofrequency. The cone angle between wave vector and ambient field is
nearly always smaller than 1°.<br><br><b>Key words:</b> Magnetospheric physics (magnetospheric
configuration and dynamics; MHD waves and instabilities; plasma waves and
instabilities) |
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| ISSN: | 0992-7689 1432-0576 |