FRQ: Field trajectories - handle k-space data

[kay-ro]

Proposed new feature or change:

For some field/continuum simulations which are performed in k-space via fourier transformation, it can be useful so store the k-space data as well.

• handle k-space grid
• handle k-space field data
• could be added to the existing file format specifications for grid as well as field files

[kai-luca]

I think this should be a feature for the 2.0 release.
But it's a really good idea.