Ds. Cai et al., Visualization and criticality of magnetotail field topology in a three-dimensional particle simulation, EARTH PL SP, 53(10), 2001, pp. 1011-1019
We present the temporal evolution of magnetic field topology in the magneto
tail with a southward IMF in order to identify the magnetic reconnection. T
he magnetic field topology is uniquely determined by the eigenvalues of the
critical points, if they are not degenerated. This is because the critical
points, their number, and the rules between them characterize the whole ma
gnetic field pattern. At the critical points, the magnetics become zero. Th
e magnetic vector field curves and surfaces are both integrated out along t
he principal directions of certain classes of critical points including the
Earth's dipole magnetic field. The skeleton that includes the critical poi
nts, characteristic curves, and surfaces provides the three-dimensional top
ological structure of the reconnection. The change of the skeleton, i.e. th
e change of the topology, has revealed the occurrence of magnetic reconnect
ion. Namely, three-dimensional "X-points" or the more-than-two critical poi
nts that are saddle and connected each other are unstable and can move, van
ish, and generated.