Institut national de recherche scientifique français Univerité Pierre et Marie Curie Université Paris Diderot - Paris 7

Wave turbulence and dissipation in solar and stellar winds

mardi 14 janvier 2020, par Victor RĂ©ville (IRAP)

Vendredi 24 janvier 2020 à 11h00 , Lieu : Salle de confĂ©rence du bâtiment 17

Solar-like stars, and particularly the Sun, exhibit hot coronae that can reach temperatures of several million Kelvin, consequently driving expanding winds. Mechanisms for the heating and the acceleration of these winds are still largely debated, however, the thorough study of the solar wind for the past 60 years has motivated an important focus on wave turbulence. In this talk, I will review and discuss models for Alfvén wave propagation and turbulent cascade, which eventually leads to dissipation. In the light of a recent study, we will see how compressible effects -namely the parametric decay instability- can be involved in the generation of a turbulent power spectrum from a narrow band emission of Alfvén waves at the chromosphere. I will then discuss how to implement turbulent transport and dissipation in global models and compare numerical simulations with the first results of the Parker Solar Probe. I will show how these global simulations are useful to make the remote sensing / in situ connection in the context of PSP and Solar Orbiter. Finally, zooming out to a more stellar context, I will discuss the important constraints that need to be taken into account to transpose solar models to other solar-like stars.