J’ai le plaisir de vous inviter à ma soutenance de thèse qui aura lieu le mardi 22 septembre 2026 à 13h30.
Elle se tiendra à Jussieu, dans la Salle de Conférences 105, Tour 44-54, 1e étage.
Je vous présenterai mes travaux de thèse intitulée « Emissions X par échange de charge du vent solaire dans l’environnement terrestre : Simulations numériques en soutien à la mission magnétosphérique SMILE » réalisés sous la direction de Dimitra Koutroumpa et Ronan Modolo.
La présentation sera en anglais et un lien est disponible pour ceux qui souhaitent la suivre à distance. Vous trouverez ci-dessous le résumé de la thèse ainsi que la composition du jury.
I am pleased to invite you to my thesis defence which will take place on Tuesday, 22 September 2026, at 13:30.
It will be held in Jussieu, Conference Room 105, Tower 44-54, 1st floor.
I will present my thesis entitled ‘Solar wind charge exchange X-ray emissions in the near-Earth environment: Numerical simulations in support of the SMILE magnetospheric mission’ supervised by Dimitra Koutroumpa and Ronan Modolo.
The presentation will be in English, and a link is available for those who are unable to attend in person.
Below you will find a summary of the thesis and the composition of the evaluation committee.
Evaluation committee :
- Rapporteurs: Minna Palmroth and Vincent Maget
- Examinateurs: Sébastien Galtier, Caitriona Jackman, Benoit Lavraud
Abstract:
The interaction between the solar wind and the terrestrial magnetic field forms a dynamic magnetosphere whose boundaries respond continuously to variations in the upstream plasma and interplanetary magnetic field. Soft X-ray emission produced by solar wind charge exchange (SWCX) offers a technique to remotely detect this interaction globally. In preparation for the SMILE mission, this thesis develops numerical methods to model the SWCX emissions and to derive the magnetopause location from X-ray images.
At first, we present the LATMOS Test Particle (LaTeP) model which traces multiply charged solar wind ions through electromagnetic fields input by other simulations and calculates the corresponding SWCX emission. The model resolves species-dependent ion transport and separates solar-wind-origin ions from magnetospheric plasma.
Then we develop a dynamic version, D-LaTeP, to use time-sequential input electromagnetic fields to simulate the temporal evolution of the SWCX near the magnetosphere. We validate D-LaTeP using two real-time solar wind cases.
We then apply D-LaTeP to a coronal mass ejection event and compare the simulation results with XMM-Newton observations. These simulations show that the model reproduces the global motion of the dayside boundaries and the main temporal evolution of the X-ray intensity observed by XMM-Newton. They also indicate that solar wind heavy ions can enter the magnetosphere under strong upstream conditions and produce emission inside magnetosphere.
Finally, we propose a Hough-like method to retrieve the magnetopause from synthetic SMILE images by fitting the projected tangent curves of analytical magnetopause surfaces. The results demonstrate the potential of soft X-ray imaging for global magnetospheric monitoring, while also showing that photon statistics, viewing geometry, exospheric density, and inner-magnetospheric emission need to be carefully considered in the interpretation of such observations.
(Transmis par Qiuyu Xu)