Enforcing Meshplanes

For bodies of revolution, gd1 has no algorithm to decide where to place the meshplanes. We have to give gd1 a hint. We want to have meshplanes exactly at the bottom and the top of our cavity. We specify the wanted locations of the meshplanes in the section -mesh. We edit our inputfile so that it contains

   -mesh
      #
      # enforce two meshplanes, at the bottom and the top of the cavity:
      #
      zfixed(2, -GapLength/2, GapLength/2 )

The semantics of zfixed(N, Z0, Z1) is: N is the number of meshplanes to enforce, the meshplanes are placed equidistantly between Z0 and Z1. It is allowed to specify positions of mesh-planes that are outside of the computational volume.

Since we have had already a quite fine mesh, the effect is not visible and is not shown here.

There is not much gain if one tries to enforce meshplanes at the outer radii of the cavity and the beam-pipes.