Kinetic instabilities and plasma turbulence in the expanding solar wind: observations and simulations

Astronomy Unit Seminars
Lorenzo Matteini
David Tsiklauri
January 29th, 2016 at 14:30
GO Jones Room 610

Thanks to its accessibility to in situ explorations, the Heliosphere represents an incredible laboratory for plasma astrophysics where universal processes, such us fluid and kinetic instabilities, plasma turbulence, and particle acceleration, can be investigated in detail. Studies of the complex properties of particles and fields are possible through measurements made in interplanetary space at different distance from the Sun, and allow us to shed light on the interactions that control energy exchanges in weakly collisional plasmas. In this talk I will discuss recent achievements in the modelling of solar wind plasma from fluid to kinetic scales, by means of multi-scale numerical simulations and I will compare the results with direct spacecraft observations. I will in particular focus on the interplay between fluctuations associated to plasma instabilities driven by non-Maxwellian particle distributions and the ubiquitous turbulent cascade which transports energy from large (MHD) to small (kinetic) scales in space plasmas. Links to the forthcoming Solar Orbiter and Solar Probe Plus  missions will be discussed, as well as to other astrophysical environments where similar processes are thought to be at work.