[Le champ magnétique galactique et la déflexion des rayons cosmiques ultra-énergétiques]
Notre compréhension du champ magnétique galactique (GMF) s'est considérablement améliorée au cours des dernières années, mais reste largement insuffisante. À titre d'illustration, le modèle GMF de Jansson et Farrar (2012) (JF12) est décrit ici, en insistant sur la manière dont il est contraint et sur ses caractéristiques, qu'elles soient robustes ou, au contraire, susceptibles de changer avec l'amélioration de la modélisation et des données. Les besoins les plus urgents pour la prochaine phase de modélisation sont, d'une part, un modèle plus réaliste de la distribution des électrons relativistes (ce qui permettra de réduire les incertitudes systématiques associées à l'interprétation des données d'émissions synchrotron) et, d'autre part, une meilleure compréhension théorique de l'origine du champ galactique cohérent sur les grandes échelles (afin de développer une meilleure paramétrisation phénoménologique du champs). Le modèle JF12, même dans sa version actuelle, permet de formuler quelques conclusions importantes sur la déflexion des RCUHE dans la Galaxie.
Our understanding of the Galactic magnetic field (GMF) has increased considerably in recent years, while at the same time remaining far from adequate. By way of illustration, the Jansson and Farrar (2012) (JF12) GMF model is described, emphasizing how it is constrained and which features are robust or likely to change, as modeling and constraining data improve. The most urgent requirements for the next phase of modeling are a more realistic model for the relativistic electron distribution (in order to reduce the systematic error associated with interpreting synchrotron data) and a better theoretical understanding of the origin of the large-scale coherent field (in order to develop a better phenomenological parameterization of the field). Even in its current stage of development, the JF12 model allows some important conclusions about UHECR deflections in the GMF to be formulated.
Mot clés : RCUHE, Champs magnétique galactique, Déflexions magnétiques
@article{CRPHYS_2014__15_4_339_0,
author = {Glennys R. Farrar},
title = {The {Galactic} magnetic field and ultrahigh-energy cosmic ray deflections},
journal = {Comptes Rendus. Physique},
pages = {339--348},
publisher = {Elsevier},
volume = {15},
number = {4},
year = {2014},
doi = {10.1016/j.crhy.2014.04.002},
language = {en},
}
Glennys R. Farrar. The Galactic magnetic field and ultrahigh-energy cosmic ray deflections. Comptes Rendus. Physique, Volume 15 (2014) no. 4, pp. 339-348. doi : 10.1016/j.crhy.2014.04.002. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2014.04.002/
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