Computing Near Field in a Periodic System

[Allison Green]

Hi all,

I am trying to compute the near field at various points within a system that has periodic boundaries - specifically the |E_total|. I have been able to do near field calculations using the graphical_output.show_near_field module of smuthi.postprocessing (attached), but it's unclear to me if this considers the periodic boundaries since it's from the original Smuthi package. 

When trying to use the electromagnetic_nearfield module of smuthi.periodicboundaries.post_processing, I'm having trouble computing the correct quantity. The function asks for a smuthi.field_expansion.PlaneWaveExpansion as input, but it appears that the total field can only be computed as a PiecewiseFieldExpansion object (total_periodic_field_piecewise_expansion). The example in the docs uses the transmitted_plane_wave_expansion (which I have been able to run, but this does not help calculate total fields inside the particle arrangement - returns all 0's).

I'm wondering if it is ok to use the original show_near_field for this calculation (since it's post processing after the simulation, is periodicity already accounted for?)? The note in the internal code above the periodic one states: "Field evaluation follows the procedure of Smuthi's "old (legacy)" electric field and magnetic field routines, basically identical to the field evaluation of any plane wave, but as a sum of discrete propagation angles (instead of an integral)". Or, is there a way to convert the total field piecewise expansion into a plane wave expansion for use with the periodic near field module? (Or other suggestions for appropriate inputs?)

Thanks!

Allison