Interaction of suprathermal solar wind electron fluxes with sheared whistler waves: fan instability
Several in situ measurements performed in the solar wind evidenced that solar type III radio bursts were some-times associated with locally excited Langmuir waves, high-energy electron fluxes and low-frequency electrostatic and electromagnetic waves; moreover, in some cases, the simultaneous...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2003-07-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/21/1393/2003/angeo-21-1393-2003.pdf |
| _version_ | 1819089841321672704 |
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| author | C. Krafft A. Volokitin |
| author_facet | C. Krafft A. Volokitin |
| author_sort | C. Krafft |
| collection | DOAJ |
| description | Several in situ
measurements performed in the solar wind evidenced that solar type III radio
bursts were some-times associated with locally excited Langmuir waves,
high-energy electron fluxes and low-frequency electrostatic and electromagnetic
waves; moreover, in some cases, the simultaneous identification of energetic
electron fluxes, Langmuir and whistler waves was performed. This paper shows
how whistlers can be excited in the disturbed solar wind through the so-called
"fan instability" by interacting with energetic electrons at the
anomalous Doppler resonance. This instability process, which is driven by the
anisotropy in the energetic electron velocity distribution along the ambient
magnetic field, does not require any positive slope in the suprathermal
electron tail and thus can account for physical situations where plateaued
reduced electron velocity distributions were observed in solar wind plasmas in
association with Langmuir and whistler waves. Owing to linear calculations of
growth rates, we show that for disturbed solar wind conditions (that is, when
suprathermal particle fluxes propagate along the ambient magnetic field), the
fan instability can excite VLF waves (whistlers and lower hybrid waves) with
characteristics close to those observed in space experiments.<br><br><b>Key words. </b>Space plasma physics
(waves and instabilities) – Radio Science (waves in plasma) – Solar
physics, astrophysics and astronomy (radio emissions) |
| first_indexed | 2024-12-21T22:14:20Z |
| format | Article |
| id | doaj.art-a2c01336fdd8410e97b6c7d3bf400d74 |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-21T22:14:20Z |
| publishDate | 2003-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-a2c01336fdd8410e97b6c7d3bf400d742022-12-21T18:48:29ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762003-07-01211393140310.5194/angeo-21-1393-2003Interaction of suprathermal solar wind electron fluxes with sheared whistler waves: fan instabilityC. Krafft0A. Volokitin1Laboratoire de Physique des Gaz et des Plasmas, Université Paris Sud, 91405 Orsay Cedex, FranceInstitute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation, Academy of Sciences, Troitsk, Moscow Region, 142190, RussiaSeveral in situ measurements performed in the solar wind evidenced that solar type III radio bursts were some-times associated with locally excited Langmuir waves, high-energy electron fluxes and low-frequency electrostatic and electromagnetic waves; moreover, in some cases, the simultaneous identification of energetic electron fluxes, Langmuir and whistler waves was performed. This paper shows how whistlers can be excited in the disturbed solar wind through the so-called "fan instability" by interacting with energetic electrons at the anomalous Doppler resonance. This instability process, which is driven by the anisotropy in the energetic electron velocity distribution along the ambient magnetic field, does not require any positive slope in the suprathermal electron tail and thus can account for physical situations where plateaued reduced electron velocity distributions were observed in solar wind plasmas in association with Langmuir and whistler waves. Owing to linear calculations of growth rates, we show that for disturbed solar wind conditions (that is, when suprathermal particle fluxes propagate along the ambient magnetic field), the fan instability can excite VLF waves (whistlers and lower hybrid waves) with characteristics close to those observed in space experiments.<br><br><b>Key words. </b>Space plasma physics (waves and instabilities) – Radio Science (waves in plasma) – Solar physics, astrophysics and astronomy (radio emissions)https://www.ann-geophys.net/21/1393/2003/angeo-21-1393-2003.pdf |
| spellingShingle | C. Krafft A. Volokitin Interaction of suprathermal solar wind electron fluxes with sheared whistler waves: fan instability Annales Geophysicae |
| title | Interaction of suprathermal solar wind electron fluxes with sheared whistler waves: fan instability |
| title_full | Interaction of suprathermal solar wind electron fluxes with sheared whistler waves: fan instability |
| title_fullStr | Interaction of suprathermal solar wind electron fluxes with sheared whistler waves: fan instability |
| title_full_unstemmed | Interaction of suprathermal solar wind electron fluxes with sheared whistler waves: fan instability |
| title_short | Interaction of suprathermal solar wind electron fluxes with sheared whistler waves: fan instability |
| title_sort | interaction of suprathermal solar wind electron fluxes with sheared whistler waves fan instability |
| url | https://www.ann-geophys.net/21/1393/2003/angeo-21-1393-2003.pdf |
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