Problem with fieldexpr

[Gerrit Bruhaug]

Hi all,

I am using the fieldexpr command to crudely place in some fields we think are present in electron radiographs of laser ablation experiments. I have done this before quite successfully with electric fields and am now trying some more complicated magnetic fields. I am using Bphi to define the field and create six loops/ring shaped fields at 45 degree angles to each other, all 0.1 mm long and I vary the radius and field strength. This works great and replicates some of our radiographs, but once I make the loops with a radius under 1 mm all of a sudden four of the loops won't generate! Any ideas why this would be happening? I have tried adjusting the tolerance and had no luck. Thank you for any help you can provide!

-Gerrit