Tilted grids

[austin-hoover]

The grid size adapts to the beam size in x/y/z. Could we add the option to also account for linear correlations between the three planes? For example, if there is a strong x-y correlation in the bunch, the resolution could be improved by applying a rotation to remove the linear correlation, calculating the space charge kicks, and then undoing the rotation to get the kicks in the original frame.

[shishlo]

Do we have a specific problem (e.g., flat-beam dynamics) that needs to be studied? If so, you can add this feature. If not, why do it?

[austin-hoover]

This could be relevant for beams with non-equal eigenemittances, i.e. rotating beams. For example, Danilov's "eigenpainting" method generates such a beam in an accumulator ring. In this case the x-y beam ellipse will be round at some locations but will be strongly tilted at other locations.

[shishlo]

Ok. In this case, I agree. Go ahead with this modifications. I only suggest making this a feature that user can switch "On/Off". For linacs bunches this is an unusual situation.