Event Details

The multi-scale physics of the solar wind: Theoretical, numerical, and observational challenges by Dr Daniel Verscharen (University College London – Mullard Space Science Lab.)

Abstract: Magnetised space plasmas exhibit collective plasma behaviour associated with its characteristic spatial and temporal scales. In the solar wind, the characteristic length scales include the size of the heliosphere, the collisional mean free paths of all species, their inertial lengths, their gyration radii, and their Debye lengths. The characteristic timescales include the plasma expansion times, the collision times, and the periods associated with gyration, waves, and oscillations. I will discuss the multi-scale nature of the solar wind and the processes associated with these different scales. I will emphasise that couplings of processes across scales are important for the global dynamics and thermodynamics of the solar wind. However, we face major challenges in our investigation of these processes with existing theoretical, numerical, and observational approaches. These processes include expansion effects, non-equilibrium distribution functions, collisions, waves and turbulence, and kinetic micro-instabilities. I will also give an outlook into future space missions for multi-scale plasma studies that will help us overcome some of the challenges.