التفاصيل البيبلوغرافية
| العنوان: |
Multi-instrument and modelling studies of the ionospheres at Earth and Mars |
| المؤلفون: |
Grandin, M. (Maxime) |
| المساهمون: |
Kozlovsky, A. (Alexander), Marchaudon, A. (Aurélie), Aikio, A. (Anita), Ulich, T. (Thomas) |
| بيانات النشر: |
University of Oulu |
| سنة النشر: |
2018 |
| المجموعة: |
Jultika - University of Oulu repository / Oulun yliopiston julkaisuarkisto |
| مصطلحات موضوعية: |
Martian atmosphere and ionosphere, auroral ionosphere, ionosphere–magnetosphere coupling, radio-occultation, solar wind high-speed streams, Marsin ilmakehä ja ionosfääri, ionosfääri–magnetosfääri-kytkentä, nopeat aurinkotuulivirtaukset, radio-okkultaatio, revontuli-ionosfääri, atmosphère et ionosphère martiennes, couplages ionosphère{magnétosphère, courants de vent solaire rapide, ionosphère aurorale |
| الوصف: |
This thesis studies the ionospheres of the Earth and Mars by combining the observations of versatile instruments providing information on various aspects of the planetary environments. The work on the terrestrial ionosphere focuses particularly on solar wind–magnetosphere–ionosphere coupling, while the work on the Martian ionosphere is based on the development of a new approach to analyse radio-occultation data to retrieve the atmospheric and ionospheric profiles. In the Earth’s ionosphere, two papers study the effects of solar wind high-speed streams on the ionospheric F-region peak electron density and on cosmic noise absorption resulting from the precipitation of energetic (>30 keV) electrons into the D region. For the first paper, a modified version of the superposed epoch analysis method, called phase-locked superposed epoch analysis method, was developed. The main finding is that a depletion near the F-region peak takes place in the afternoon and evening sectors during high-speed stream events. This could be explained by an increase in the electron loss rate as a consequence of ion-neutral frictional heating, which enhances the ion temperature and leads to neutral atmosphere expansion. In addition, dayside and post-midnight F-peak electron density increases are observed, probably related to soft particle precipitation. The second study reveals that cosmic noise absorption occurs during up to 4 days after the arrival of a high-speed stream, as substorm-injected energetic electrons precipitate in the midnight to early-afternoon ionosphere, principally at auroral latitudes. A third study reports for the first time observations of a modulation of cosmic noise absorption at periods near 10 s, associated with pulsating aurora. This suggests that the energetic component of the precipitating ux is modulated consistently with the auroral (1–10 keV) energies. At Mars, radio-occultation experiments have been performed by the Mars Express spacecraft since 2004. In this thesis, a new data analysis approach ... |
| نوع الوثيقة: |
doctoral or postdoctoral thesis |
| وصف الملف: |
application/pdf |
| اللغة: |
English |
| Relation: |
info:eu-repo/semantics/altIdentifier/pissn/1456-3673 |
| الاتاحة: |
http://urn.fi/urn:isbn:9789526216157 |
| Rights: |
info:eu-repo/semantics/openAccess ; © University of Oulu, 2017 |
| رقم الانضمام: |
edsbas.CF3E90B5 |
| قاعدة البيانات: |
BASE |