Angular momentum balance in the solar tachocline - a laminar model

By Toby Wood (DAMTP)

Room D18 (2nd floor) at ENS, 24 rue Lhomond, 13:00 to 13:45

The Sun's radiation zone (beneath 0.7R) rotates uniformly, despite the differential rotation of the overlying convection zone. In high latitudes, this uniform rotation can be sustained by the prograde Lorentz torque from a large-scale magnetic field confined to the radiation zone. Outward diffusion of this magnetic field balances inward advection by the convection zone's meridional circulation, as envisaged by Gough & McIntyre (1998).

We present a laminar model of this "magnetic confinement layer", and describe exact similarity solutions in the limit of strong stratification. For realistic parameter values, the model can hold over the entire high-latitude region.

Interstellar ices in the lab: the importance of being water

By Emanuele Congiu (Cergy-Pontoise)

Room D18 (2nd floor) at ENS, 24 rue Lhomond, 13:00 to 13:45

Solid water is a very abundant material. Indeed, it is believed to be the most abundant condensed material in the Universe, thanks to its propensity to remain as a deposit on interstellar dust particles in dense clouds.

In this talk, I shall present how we are able to grow realistic water ice analogues in the laboratory, to choose their structure, to model their morphology, and to use them as a substrate fit for the surface chemistry leading to molecular complexity in space. Water ice will turn out to be a unique and rich case study for laboratory simulations of ices at low temperatures in an astrophysical environment.