Enhanced ion acoustic fluctuations and ion outflows
A number of observations showing enhanced ion acoustic echoes observed by means of incoherent scatter radars have been reported in the literature. The received power is extremely enhanced by up to 1 or 2 orders of magnitude above usual values, and it is mostly contained in one of the two ion acousti...
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ftdoajarticles:oai:doaj.org/article:0268721ff8f0440381a12c561db497cb 2023-05-15T16:04:47+02:00 Enhanced ion acoustic fluctuations and ion outflows F. R. E. Forme D. Fontaine 1999-02-01T00:00:00Z https://doi.org/10.1007/s00585-999-0182-6 https://doaj.org/article/0268721ff8f0440381a12c561db497cb EN eng Copernicus Publications https://www.ann-geophys.net/17/182/1999/angeo-17-182-1999.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.1007/s00585-999-0182-6 0992-7689 1432-0576 https://doaj.org/article/0268721ff8f0440381a12c561db497cb Annales Geophysicae, Vol 17, Pp 182-189 (1999) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 1999 ftdoajarticles https://doi.org/10.1007/s00585-999-0182-6 2022-12-31T03:25:12Z A number of observations showing enhanced ion acoustic echoes observed by means of incoherent scatter radars have been reported in the literature. The received power is extremely enhanced by up to 1 or 2 orders of magnitude above usual values, and it is mostly contained in one of the two ion acoustic lines. This spectral asymmetry and the intensity of the received signal cannot be resolved by the standard analysis procedure and often causes its failure. As a result, and in spite of a very clear spectral signature, the analysis is unable to fit the plasma parameters inside the regions of ion acoustic turbulence. We present European Incoherent Scatter radar (EISCAT) observations of large ion outflows associated with the simultaneous occurrence of enhanced ion acoustic echoes. The ion fluxes can reach 10 14 m -2 s -1 at 800 km altitude. From the very clear spectral signatures of these echoes, a method is presented to extract estimates of the electron temperature and the ion drift within the turbulent regions. It is shown that the electron gas is strongly heated up to 11 000 K. Also electron temperature gradients of about 0.02 K/m exist. Finally, the estimates of the electron temperature and of the ion drift are used to study the possible implications for the plasma transport inside turbulent regions. It is shown that strong electron temperature gradients cause enhancement of the ambipolar electric field and can account for the observed ion outflows. Key words. Ionosphere (auroral ionosphere; ionosphere · magnetosphere interactions; plasma waves and instabilities). Article in Journal/Newspaper EISCAT Directory of Open Access Journals: DOAJ Articles Annales Geophysicae 17 2 182 189 |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 F. R. E. Forme D. Fontaine Enhanced ion acoustic fluctuations and ion outflows |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
A number of observations showing enhanced ion acoustic echoes observed by means of incoherent scatter radars have been reported in the literature. The received power is extremely enhanced by up to 1 or 2 orders of magnitude above usual values, and it is mostly contained in one of the two ion acoustic lines. This spectral asymmetry and the intensity of the received signal cannot be resolved by the standard analysis procedure and often causes its failure. As a result, and in spite of a very clear spectral signature, the analysis is unable to fit the plasma parameters inside the regions of ion acoustic turbulence. We present European Incoherent Scatter radar (EISCAT) observations of large ion outflows associated with the simultaneous occurrence of enhanced ion acoustic echoes. The ion fluxes can reach 10 14 m -2 s -1 at 800 km altitude. From the very clear spectral signatures of these echoes, a method is presented to extract estimates of the electron temperature and the ion drift within the turbulent regions. It is shown that the electron gas is strongly heated up to 11 000 K. Also electron temperature gradients of about 0.02 K/m exist. Finally, the estimates of the electron temperature and of the ion drift are used to study the possible implications for the plasma transport inside turbulent regions. It is shown that strong electron temperature gradients cause enhancement of the ambipolar electric field and can account for the observed ion outflows. Key words. Ionosphere (auroral ionosphere; ionosphere · magnetosphere interactions; plasma waves and instabilities). |
format |
Article in Journal/Newspaper |
author |
F. R. E. Forme D. Fontaine |
author_facet |
F. R. E. Forme D. Fontaine |
author_sort |
F. R. E. Forme |
title |
Enhanced ion acoustic fluctuations and ion outflows |
title_short |
Enhanced ion acoustic fluctuations and ion outflows |
title_full |
Enhanced ion acoustic fluctuations and ion outflows |
title_fullStr |
Enhanced ion acoustic fluctuations and ion outflows |
title_full_unstemmed |
Enhanced ion acoustic fluctuations and ion outflows |
title_sort |
enhanced ion acoustic fluctuations and ion outflows |
publisher |
Copernicus Publications |
publishDate |
1999 |
url |
https://doi.org/10.1007/s00585-999-0182-6 https://doaj.org/article/0268721ff8f0440381a12c561db497cb |
genre |
EISCAT |
genre_facet |
EISCAT |
op_source |
Annales Geophysicae, Vol 17, Pp 182-189 (1999) |
op_relation |
https://www.ann-geophys.net/17/182/1999/angeo-17-182-1999.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.1007/s00585-999-0182-6 0992-7689 1432-0576 https://doaj.org/article/0268721ff8f0440381a12c561db497cb |
op_doi |
https://doi.org/10.1007/s00585-999-0182-6 |
container_title |
Annales Geophysicae |
container_volume |
17 |
container_issue |
2 |
container_start_page |
182 |
op_container_end_page |
189 |
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1766400413541597184 |