Studies of ionospheric parameters by means of electron plasma lines observed by EISCAT
ISBN: 8290487924, 9788290487923 This work presents a study of the electron plasma lines observed by the incoherent scatter radar EISCAT. The work is focusing on two parts. On one hand, the design of a plasma line experiment for the EISCAT system with an improved spatial resolution. On the other hand...
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1998
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ftunivnantes:oai:HAL:tel-00481443v2 2023-05-15T16:04:15+02:00 Studies of ionospheric parameters by means of electron plasma lines observed by EISCAT Étude de paramètres ionosphériques à l'aide des raies de plasma électroniques observées à EISCAT Guio, P. Université Joseph Fourier - Grenoble 1 (UJF) Université Joseph-Fourier - Grenoble I Wlodek Kofman 1998-12-18 https://theses.hal.science/tel-00481443 https://theses.hal.science/tel-00481443v2/document https://theses.hal.science/tel-00481443v2/file/fullthesis-hr.pdf en eng HAL CCSD tel-00481443 https://theses.hal.science/tel-00481443 https://theses.hal.science/tel-00481443v2/document https://theses.hal.science/tel-00481443v2/file/fullthesis-hr.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-00481443 Astrophysics [astro-ph]. Université Joseph-Fourier - Grenoble I, 1998. English. ⟨NNT : ⟩ electron velocity distribution function dispersion relation Langmuir waves EISCAT distributions des vitesses électronique dispersion de relation ondes de Langmuir [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [SDU]Sciences of the Universe [physics] [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/doctoralThesis Theses 1998 ftunivnantes 2023-03-08T03:12:23Z ISBN: 8290487924, 9788290487923 This work presents a study of the electron plasma lines observed by the incoherent scatter radar EISCAT. The work is focusing on two parts. On one hand, the design of a plasma line experiment for the EISCAT system with an improved spatial resolution. On the other hand, the comparison of the plasma line data collected with the EISCAT radar with an improved model for the intensity and the Doppler frequency shift of the plasma lines. In order to improve the spatial resolution of the plasma line experiment we have designed the first experiment that implements the recent technique of alternating code. The experiment has been run successfully with an altitude resolution of 3 km as opposed to 40-50 km obtained with the conventional techniques. Because it is very difficult to construct a self-consistent model of the velocity distribution function encompassing all of the relevant energy range, we have made an ad hoc model by separating the distribution into two parts: the thermal and the supra-thermal population. The thermal population is represented by the Spitzer function that takes into account the effect of an electric field and/or a temperature gradient. The supra-thermal population is derived from the angular energy flux of the supra-thermal electrons calculated by a numerical electron transport model. A numerical code has been developed to calculate the dielectric function and the reduced one-dimensional velocity distribution for any arbitrary two-dimensional velocity distribution which are needed to model the intensity and the Doppler frequency shift of the plasma lines. We have been able to reproduce peculiar features of the intensity as well as the Doppler shift of the plasma lines with data collected with the EISCAT VHF radar. Especially, two sharp peaks in the supra-thermal distribution were identified as the signature of photo-ionisation of N_2 and O and were observed in the measured data. The effect of the temperature gradient\ - which produces a decisive correction to the ... Doctoral or Postdoctoral Thesis EISCAT Université de Nantes: HAL-UNIV-NANTES Langmuir ENVELOPE(-67.150,-67.150,-66.967,-66.967) |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
electron velocity distribution function dispersion relation Langmuir waves EISCAT distributions des vitesses électronique dispersion de relation ondes de Langmuir [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [SDU]Sciences of the Universe [physics] [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
electron velocity distribution function dispersion relation Langmuir waves EISCAT distributions des vitesses électronique dispersion de relation ondes de Langmuir [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [SDU]Sciences of the Universe [physics] [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Guio, P. Studies of ionospheric parameters by means of electron plasma lines observed by EISCAT |
topic_facet |
electron velocity distribution function dispersion relation Langmuir waves EISCAT distributions des vitesses électronique dispersion de relation ondes de Langmuir [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [SDU]Sciences of the Universe [physics] [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
ISBN: 8290487924, 9788290487923 This work presents a study of the electron plasma lines observed by the incoherent scatter radar EISCAT. The work is focusing on two parts. On one hand, the design of a plasma line experiment for the EISCAT system with an improved spatial resolution. On the other hand, the comparison of the plasma line data collected with the EISCAT radar with an improved model for the intensity and the Doppler frequency shift of the plasma lines. In order to improve the spatial resolution of the plasma line experiment we have designed the first experiment that implements the recent technique of alternating code. The experiment has been run successfully with an altitude resolution of 3 km as opposed to 40-50 km obtained with the conventional techniques. Because it is very difficult to construct a self-consistent model of the velocity distribution function encompassing all of the relevant energy range, we have made an ad hoc model by separating the distribution into two parts: the thermal and the supra-thermal population. The thermal population is represented by the Spitzer function that takes into account the effect of an electric field and/or a temperature gradient. The supra-thermal population is derived from the angular energy flux of the supra-thermal electrons calculated by a numerical electron transport model. A numerical code has been developed to calculate the dielectric function and the reduced one-dimensional velocity distribution for any arbitrary two-dimensional velocity distribution which are needed to model the intensity and the Doppler frequency shift of the plasma lines. We have been able to reproduce peculiar features of the intensity as well as the Doppler shift of the plasma lines with data collected with the EISCAT VHF radar. Especially, two sharp peaks in the supra-thermal distribution were identified as the signature of photo-ionisation of N_2 and O and were observed in the measured data. The effect of the temperature gradient\ - which produces a decisive correction to the ... |
author2 |
Université Joseph Fourier - Grenoble 1 (UJF) Université Joseph-Fourier - Grenoble I Wlodek Kofman |
format |
Doctoral or Postdoctoral Thesis |
author |
Guio, P. |
author_facet |
Guio, P. |
author_sort |
Guio, P. |
title |
Studies of ionospheric parameters by means of electron plasma lines observed by EISCAT |
title_short |
Studies of ionospheric parameters by means of electron plasma lines observed by EISCAT |
title_full |
Studies of ionospheric parameters by means of electron plasma lines observed by EISCAT |
title_fullStr |
Studies of ionospheric parameters by means of electron plasma lines observed by EISCAT |
title_full_unstemmed |
Studies of ionospheric parameters by means of electron plasma lines observed by EISCAT |
title_sort |
studies of ionospheric parameters by means of electron plasma lines observed by eiscat |
publisher |
HAL CCSD |
publishDate |
1998 |
url |
https://theses.hal.science/tel-00481443 https://theses.hal.science/tel-00481443v2/document https://theses.hal.science/tel-00481443v2/file/fullthesis-hr.pdf |
long_lat |
ENVELOPE(-67.150,-67.150,-66.967,-66.967) |
geographic |
Langmuir |
geographic_facet |
Langmuir |
genre |
EISCAT |
genre_facet |
EISCAT |
op_source |
https://theses.hal.science/tel-00481443 Astrophysics [astro-ph]. Université Joseph-Fourier - Grenoble I, 1998. English. ⟨NNT : ⟩ |
op_relation |
tel-00481443 https://theses.hal.science/tel-00481443 https://theses.hal.science/tel-00481443v2/document https://theses.hal.science/tel-00481443v2/file/fullthesis-hr.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766399954664816640 |