3D Magnetic Reconnection
3-D scenario of the inter-linked magnetic configuration and conjugate observations of ion distributions by the CIS instrument of Cluster spacecraft 1 and Cluster spacecraft 3. For reference, distributions 1 and 2 are typical of measurements made around 0510 UT on opposite sides of the nominal quasi-impermeable magnetopause.
In flux tube 1, SC1 observes a hot (~330 eV), isotropic and dense (~10 cm-3) plasma ‘bubble' (distribution 3, at 0512:44). These are decelerated magnetosheath particles associated with the transient reconnection.
On the magnetospheric side of structure 1 (distribution 4), SC3, magnetically connected to the bubble, measures a hot population (6 cm-3, ~360 eV, at 0514) moving in the solar direction, along the local B-field. It has phase space characteristics very similar to those of distribution 3, which indicates that magnetosheath particles are entering the magnetosphere along the reconnected field lines.
Distribution 5 (from SC1) displays a convincing D-shape with a cut-off at the HT velocity (dashed red line) as expected in the tailward branch of a reconnection site (Figure 4 of Louarn et al., 2004).