Type II supernovae modelisation: neutrinos transport simulation
Description
A modelisation of neutrino transport in type II supernovae is presented. The first part is a description of hydrodynamics and radiative processes responsible of supernovae explosions. Macroscopic aspects of these are displayed in part two. Neutrino transport theory and usual numerical methods are also developed. A new technic of coherent scattering of neutrinos on nuclei or free nucleons is proposed in the frame work of the Lorentz bifluid approximation. This method deals with all numerical artifices (flux limiting schemes, closure relationship of Eddington moments) and allows a complete and consistent determination of the time-dependent neutrino distribution function for any value of the opacity, gradient of opacity and for all (relativistic) velocity fields of the diffusive medium. Part three is dedicated to microscopic phenomena (electronic capture, chimical composition, etc) which rule neutrinos emission-absorption mechanisms. The numerical treatments of those are presented, and some applications are useful for their parametrization. Finally, an extension of the method to inelastic scattering on light particules (electrons) is described in view to study neutrinos thermalization mechanism
Availability note (English)
MF available from INIS under the Report Number.Abstract (French)
Ce memoire presente une modelisation du transport des neutrinos dans les supernovae de type II. La premiere partie de cette etude decrit les mecanismes hydrodynamiques et radiatifs responsables de l'explosion des supernovae. La theorie du transport des neutrinos et les methodes numeriques usuellement employees sont presentees dans la seconde partie. Une technique de simulation de la diffusion coherente des neutrinos sur des noyaux ou des nucleons libres est proposee dans le cadre de l'approximation du bifluide de Lorentz. Cette methode s'affranchit de tout artifice de calcul (limiteur de flux, relation de fermeture des moments d'Eddington, etc) et permet une determination complete et rigoureuse de l'evolution temporelle de la fonction de distribution angulaire des neutrinos, quels que soient l'opacite, le gradient de l'opacite et le champ de vitesse (relativiste) du milieu diffuseur. La troisieme partie est consacree aux phenomenes microscopiques (capture electronique, composition chimique, etc) qui controlent les mecanismes d'emission-absorption des neutrinos. Les traitements numeriques de ces problemes sont presentes et quelques applications permettent de les parametriser. Enfin, l'extension de la methode a l'etude de la thermalisation des neutrinos par diffusion inelastique sur des particules legeres (electrons) est exposeeFiles
21069361.pdf
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Additional details
Additional titles
- Original title (French)
- Modelisation des supernovae de type II: simulation du transport des neutrinos
Publishing Information
- Imprint Pagination
- 214 p.
- Report number
- FRCEA-TH--266
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 21069361
- Subject category
- S79: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- ANGULAR DISTRIBUTION; GRAVITATIONAL COLLAPSE; HYDRODYNAMICS; NEUTRINO REACTIONS; NEUTRINOS; SCATTERING; SUPERNOVAE; TRANSPORT THEORY
- Descriptors DEC
- BINARY STARS; DISTRIBUTION; ELEMENTARY PARTICLES; ERUPTIVE VARIABLE STARS; FERMIONS; FLUID MECHANICS; LEPTON REACTIONS; LEPTONS; MASSLESS PARTICLES; MECHANICS; NUCLEAR REACTIONS; STARS; VARIABLE STARS