  The process of magnetic reconnection when studied in Nature or when modeled
in 3D simulations differs in one key way from the standard 2D paradigmatic
cartoon: it is accompanied by much fluctuations in the electromagnetic fields
and plasma properties. We developed a diagnostics to study the spectrum of
fluctuations in the various regions around a reconnection site. We define the
regions in terms of the local value of the flux function that determines the
distance form the reconnection site, with positive values in the outflow and
negative values in the inflow. We find that fluctuations belong to two very
different regimes depending on the local plasma beta (defined as the ratio of
plasma and magnetic pressure). The first regime develops in the reconnection
outflows where beta is high and is characterized by a strong link between
plasma and electromagnetic fluctuations leading to momentum and energy
exchanges via anomalous viscosity and resistivity. But there is a second, low
beta regime: it develops in the inflow and in the region around the separatrix
surfaces, including the reconnection electron diffusion region itself. It is
remarkable that this low beta plasma, where the magnetic pressure dominates,
remain laminar even though the electromagnetic fields are turbulent.
