How to change E_inc setting to arbitrary magnitude and or uniformity in calculation volume

Summary:

Please help me understand how to manipulate E_inc setting

How to change E_inc setting to arbitrary magnitude and or uniformity in calculation volume

Dmitriy Boyuk (guest) 13 Nov 2016 02:48

Can you please help understand how to change E_inc setting from default. My goal is to specify a uniform E_inc inside the calculation volume regardless of particle location and refractive index. I would like to know how to define and or manipulate E_inc magnitude matrix. Your guidance on where to start and or how to proceed would be greatly appreciated.

Yours truly,
DDSCAT user

Re: How to change E_inc setting to arbitrary magnitude and or uniformity in calculation volume

pcirrus 13 Nov 2016 03:39

Look at routine EVALE which calculates electric field vector at each dipole location CXE(IA,M). Perhaps another way is to assume that wavelength of the incoming wave is very large in comparison with the size of the object.

Re: How to change E_inc setting to arbitrary magnitude and or uniformity in calculation volume

draine 13 Nov 2016 03:39

E_inc can be varied in ddscat.par, but the only meaningful changes are those regarding the polarization of the first incident plane wave (the second is always forced to be orthogonal to the first). The magnitude is immaterial because the system is assumed to respond linearly, and the Muller matrix S_ij is based on the normalized response.
The incident plane wave is taken to be have uniform absoluted value |E_inc|, throughout the calculational volume, with complex phase shifts associated with propagation.