Figure 1: Example statistics of plasma and magnetic field moments used in determination of different plasma regions. Statistics are from all available Cluster moments in the tail season of 2002 (July–October) for the specified instrument and in the tail region , . ((a)–(c)) 2D histograms of currents perpendicular (Jperp, (a)) and parallel (Jpar, (b)) to the magnetic field, as well as plasma density (c), versus plasma beta. Colours represent the number of data points in each bin, and the red lines show the median. The left most dashed vertical lines show the statistical lobe-BR boundary condition, and the right hand dashed line represents the BR-OPS boundary condition. (d) Plasma beta versus magnetic field component. Different colours represent different plasma regions—grey: lobe, blue: BR, orange: OPS, and green: IPS.