Space and laboratory collisionless plasmas are most often out of local thermodynamic equilibrium. In particular, their charged particle velocity distributions usually differ from simple Maxwellian distributions and exhibit a great variety of anisotropies and components such as suprathermal beams and tails. Here we propose a new model responsible for a "local" origin of electron suprathermal tails. The model is based on adding a high and a low frequency external forcing to the Vlasov-Poisson system of equations. The first one represents mainly the thermal noise electric field generated by charge separation effects. The second one represents the energy injection resulting from the energy cascade generated by the large scale fluid (MHD) turbulence. We find that in typical solar wind conditions, our model could be the base of a full three dimensional, electromagnetic model capable of explaining the local generation of the electron halo population observed on the electron distribution function.
A one dimensional, electrostatic Vlasov model for the generation of suprathermal electron tails in solar wind conditions
CALIFANO, FRANCESCO;
2008-01-01
Abstract
Space and laboratory collisionless plasmas are most often out of local thermodynamic equilibrium. In particular, their charged particle velocity distributions usually differ from simple Maxwellian distributions and exhibit a great variety of anisotropies and components such as suprathermal beams and tails. Here we propose a new model responsible for a "local" origin of electron suprathermal tails. The model is based on adding a high and a low frequency external forcing to the Vlasov-Poisson system of equations. The first one represents mainly the thermal noise electric field generated by charge separation effects. The second one represents the energy injection resulting from the energy cascade generated by the large scale fluid (MHD) turbulence. We find that in typical solar wind conditions, our model could be the base of a full three dimensional, electromagnetic model capable of explaining the local generation of the electron halo population observed on the electron distribution function.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
