SH11C-2395
On the Role of Coulomb Collisions in the Electron Evolution Throughout the Heliosphere.
Monday, 14 December 2015
Poster Hall (Moscone South)
Simone Landi, University of Florence, Florence, Italy, Filippo G E Pantellini, CNRS, Observatoire de Paris, LESIA, Meudon, France and Lorenzo Matteini, Imperial College London, London, United Kingdom
Abstract:
Although the particle's mean free path in the solar wind is very large compared to other kinetic scales there are evidences that collision play an important role in characterising the dependence of the electron velocity distribution function as a function of heliocentric distance. In particular the interplay between Coulomb collisions and radial expansion leads to the formation of structures in the electron velocity distribution function which, based on their dominant moments, are in excellent agreement with observations in the solar wind. The heat flux carried by the electrons turns out to be modulated by the combined effect of radial expansion and Coulomb collisions and its intensity is sufficiently high to account for the repeatedly observed non adiabatic radial expansion of the electrons.
