Section: Scientific Foundations

Plasma

In the context of the Galileo satellite-positioning system, C. Besse and C. Yang, members of the ANR Iodissee project, developed a hierarchy of plasma models which describe ionospheric scintillations. This hierarchy involves many small parameters, and they introduced an asymptotic preserving scheme which allows one to take small parameters into account without solving the problem on a very fine grid [8] . The next step is to understand the fading and phase variations when waves propagate in this medium. This is a work in progress with P. Lafitte and S. Minjeaud (CNRS, Université de Nice).