write out static magnetic field map on a Cartesian grid
DUMPEMFIELDS:: write out electromagnetic field map on a 4D grid in space-time. Cartesian and cylindrical grids are supported. `DUMPEMFIELDS` is an extension of `DUMPFIELDS`.
The `DUMPEMFIELDS` statement causes _opal-cycl_ to write out electromagnetic field data on a 4D grid. Grids in a Cartesian coordinate system latexmath:[(x,y,z,t)] and a cylindrical coordinate system about the z-axis in latexmath:[(r,\phi,z,t)] are supported.
