Long range interactions in magneto-optical traps

We present in this paper a review of our work on the impact of long-range interactions on the static and dynamic behaviors of magneto-optical traps (MOT) for neutral atoms. In such systems, all forces (confinement and interaction) are mediated by light. The most obvious signature of long-range interactions is the dependence of the MOT size with number N of trapped atoms. We study in detail the scaling laws for the MOT size versus N, in a range of large N >> 10(8). We then show that the competition between confinement and repulsive interaction can lead, for N large, to a new dynamical instability characterized by spontaneous, self-sustained oscillations of the MOT. This instability is investigated experimentally and theoretically, using both a simple analytical model and a more refined numerical one.