BOUY++-based simulation of reconnection during merging of current filaments.

BOUT++ is a framework for writing fluid and plasma simulations in curvilinear
geometry. It is intended to be quite modular, with a variety of numerical
methods and time-integration solvers available. BOUT++ is primarily designed
and tested with reduced plasma fluid models in mind, but it can evolve any
number of equations, with equations appearing in a readable form.