Ion kinetic features around a lobe reconnection site

During a period of mainly northward interplanetary magnetic field (IMF), the Cluster spacecraft are skimming the high latitude southern dusk magnetopause (MP) tailward of the cusp and have frequent encounters with the MP where they detect reconnected flows for which the Walen test has been successfully verified by Retinò et al. in [12]. In the present study we discuss the kinetic signatures of reconnection which appear in the ion data in the magnetosheath boundary layer (MSBL) and in the magneto-spheric boundary layer (BL). Inspection of the distribution functions allows to infer whether the spacecraft are sunward or tailward of the reconnection site and shows that frequently, even on short time scales, the reconnection site moves from sunward to tailward (or viceversa) with respect to the spacecraft, indicating that the space-craft are usually close to the reconnection site. The reflected and transmitted magnetosheath ions, observed by CIS experiment in the MSBL and in the BL respectively, show good agreement with the predictions by kinematical considerations.