  Separators, which are in many ways the three-dimensional equivalent to
two-dimensional nulls, are important sites for magnetic reconnection. Magnetic
reconnection occurs in strong current layers which have very short length
scales. The aim of this work is to explore the nature of current layers around
separators. A separator is a special field line which lies along the
intersection of two separatrix surfaces and forms the boundary between four
topologically distinct flux domains. In particular, here the current layer
about a separator that joins two 3D nulls and lies along the intersection of
their separatrix surfaces is investigated. A magnetic configuration containing
a single separator embedded in a uniform plasma with a uniform electric current
parallel to the separator is considered. This initial magnetic setup, which is
not in equilibrium, relaxes in a non-resistive manner to form an equilibrium.
The relaxation is achieved using the 3D MHD code, Lare3d, with resistivity set
to zero. A series of experiments with varying initial current are run to
investigate the characteristics of the resulting current layers present in the
final (quasi-) equilibrium states. In each experiment, the separator collapses
and a current layer forms along it. The dimensions and strength of the current
layer increase with initial current. It is found that separator current layers
formed from current parallel to the separator are twisted. Also the collapse of
the separator is a process that evolves like an infinite-time singularity where
the length, width and peak current in the layer grow slowly whilst the depth of
the current layer decreases.
