Is it possible to predict theoretically the radus of the first ring (while interacting with plane wave) according to the plate diameter, charge and focal length of the lens? Just to estimate the precision of modelling

UPD: I’m afraid, you have a mistake in your program. Your pattern is wrong.

@kot_letova 

It will probably help @Michael Cheng a lot if you can tell him what mistake is in the program if you’ve found one. Perhaps, you could illustrate the issue with an example, that would be even better.

Take care,

David