Modified ion-Weibel instability as a possible source of wave activity at Comet 67P/Churyumov-Gerasimenko
We analytically discuss wave excitation in a homogeneous three component plasma consisting of solar wind protons, electrons and a beam of cometary water ions applied to the plasma environment of comet 67P/Churyumov-Gerasimenko. The resulting dispersion relations are studied in a solar wind rest...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-08-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/34/691/2016/angeo-34-691-2016.pdf |
| Summary: | We analytically discuss wave excitation in a homogeneous three component
plasma consisting of solar wind protons, electrons and a beam of cometary
water ions applied to the plasma environment of comet
67P/Churyumov-Gerasimenko. The resulting dispersion relations are studied in
a solar wind rest frame, where a cometary current is solely generated by the
water ion beam, and a cometary rest frame representing the rest frame of the
Rosetta spacecraft. A modified ion-Weibel instability is excited by the
cometary current and predominantly grows perpendicular to this current. The
corresponding water ion mode is connected to a frequency of about
40 mHz in agreement with wave measurements of Rosetta's
magnetometer in the cometary rest frame. Furthermore, the superposition of
the strongest growing waves result in a fan-like phase structure close to the
comet. |
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| ISSN: | 0992-7689 1432-0576 |