Date: 08 Aug 2008
Satellite: Cluster
Depicts: 3D reconstruction of Cluster spacecraft passing by a magnetic null pair
Copyright: He, J.-S. et al. [2008]

A magnetic null pair reconstructed from Cluster measurements at 09:48.25.637 UT on 1 October 2001. A type A-null and a type B-null are shown as orange and red balls, respectively, with the separator line represented by a bold pink curve connecting them.

Magnetic field lines coloured by local field strengths converge along the fan* surface (in white) to approach the A-null and then travel out along the spine* (black arrows) of the A-null. Magnetic field lines converge along the spine of the B-null and then diverge out along its fan surface (in grey).

Cluster C1, C2, C3, C4 are represented as four cubes coloured in black, red, green, and blue, respectively.

*Theoretical studies of the null pair geometry indicated that magnetic field lines close to a null have two distinct parts: a spine – where the field lines are bunched together, and a fan, where the field lines are distributed apart from each other.