Electron Dynamics and Wave-Particle Interactions in the Reconnection Diffusion Region

Abstract:

Understanding electron dynamics in the reconnection diffusion region is one of the keys to understanding microphysics of magnetic reconnection. Acceleration and trapping of electrons as well as mixing of electron populations from different sides of the reconnecting current sheet occur in the diffusion region. This results in highly non-Maxwellian electron distributions, with beams, counter-streaming populations, loss-cone and horseshoe features. Such distributions are unstable to generation of various high-frequency waves such as Langmuir, electrostatic solitary waves and electron cyclotron waves, as well as whistlers. We present detailed observations of electron distributions and related waves observed by Cluster in diffusion regions at the magnetopause and in the magnetotail. We discuss wave generation, as well as the effect the waves have on the distribution functions. We show that wave-particle interactions as well as larger-scale magnetic and electric field structure have significant effect on electron dynamics in the diffusion region.