LERMA UMR8112

Laboratoire d’Études du Rayonnement et de la Matière en Astrophysique et Atmosphères



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Offre de thèse du CNES

par Carine Bingan - publié le , mis à jour le

Appel à candidatures thèses/post-doctorats CNES

Avec les thèses et les post-doctorats du CNES : inventons l’espace du futur !

Chaque année, le CNES accorde une centaine d’allocations de recherche (thèses et post-doctorats) à des étudiants français et étrangers, dans les domaines des :
- sciences pour l’ingénieur (systèmes orbitaux, systèmes de transport spatial),
- sciences utilisatrices des moyens spatiaux (sciences de l’univers, sciences de la Terre, sciences en micropesanteur)
- sciences humaines et sociales (juridique, histoire, économie, sociologie, psychologie, etc.)

Il contribue ainsi, de façon très significative, à l’effort de formation par la recherche, des ingénieurs et des chercheurs qui inventeront les systèmes spatiaux du futur.

Nous vous informons que l’appel à candidatures CNES pour les thèses et post-doctorats est actuellement disponible sur notre site internet à cette adresse :https://cnes.fr/fr/consulter-les-offres
Vous y trouverez la liste des sujets de thèses susceptibles d’être cofinancés, les conditions et modalités de candidature ainsi que les coordonnées de vos interlocuteurs CNES.

Séminaires à venir

Vendredi 5 avril 2019, 14h00
Salle de l'atelier, Paris
The magnetized interstellar medium in the Galaxy through Faraday tomography of the radio sky
Andrea BRACCO
ENS
résumé :
The study of the diffuse Galactic interstellar medium (ISM) is both a
waypoint to investigate the processes that turn gas into stars and to
account for foreground contaminations in modern high-precision
cosmological probes of the Universe.

New structures in the diffuse ionized and magnetized ISM have been
recently observed through Faraday tomography of polarization data at low
radio frequencies. Although the physical origin of these structures
remains uncertain, interesting correlations with tracers of neutral ISM,
such as atomic hydrogen lines and interstellar dust polarization, have
been found. This opens an observational window on the first stages of
phase transition between diffuse/warm and denser/colder gas under the
presence of magnetic fields, allowing us to constrain their role in
structure formation in the ISM.

In my talk I will present an overview of the recent findings in the
diffuse Galactic ISM with the LOFAR radio polarization data. I will
highlight the relevance of a thorough statistical description of these
data both for Galactic studies and for modeling their impact as a
foreground to the detection of the atomic hydrogen 21cm hyperfine
transition from the Epoch of Reionization, a key step with the upcoming
Square Kilometre Array (SKA).
 
Vendredi 12 avril 2019, 14h00
Salle de l'atelier, Paris
Radiation magnetohydrodynamic models and spectral signatures of plasma flows accreting onto young stellar object
Salvatore COLOMBO
LERMA
résumé :
According to the largely accepted magnetospheric accretion scenario, classical T Tauri Stars (CTTSs) are young stars that accrete material from their circumstellar disk. The objective of my PhD project is to shed light on the processes governing the physics of the accreting plasma flows, through complete radiation magnetohydrodynamic models. In this talk, I will present the results obtained during my 18 month period in Paris.

First, I will focus on the results obtained from a 3D magnetohydrodynamical (MHD) model of a star-disk system. We simulate the effects of series of flares occurring on the surface of the disk. We observe that each flare produces a hot loops that links the star to the disk; all the loops build up a hot extended corona that irradiates the disk from above. Moreover, the flares trigger overpressure waves that travel through the disk and modify its configuration. Accretion funnels may be triggered by the flaring activity and thus contribute to the mass accretion rate of the star. The accretion columns can be perturbed by the flares. As a result, the streams are highly inhomogeneous, with a complex density structure, and clumped.

Second, I will provide the first assessment of the role of radiation effects on the dynamics and the structure of the impact region of the accreting column onto the stellar surface. In particular, we proved the existence of a radiative precursor in the pre-shock part of the accreting column. To achieve such a result, we have, for the first time, developed a Non Local Thermodynamic Equilibrium (non-LTE) radiation hydrodynamics model, which we implemented in the 3D MHD PLUTO code.”

 
Vendredi 21 juin 2019, 14h00
Salle de l'atelier, Paris
Accretion-driven turbulence and observational signatures
Pierre GUILLARD
IAP
 
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