actually the interaction is pretty simple i just contract and expand the particles by using the average frequency value on the 3d scale of the particle system as for the movement you see it happens because of particle vector field i created
https://camo.githubusercontent.com/5cfddeb6266b34d74e1e220a55c9ac12c7bc18af/68747470733a2f2f70352e7a6475736572636f6e74656e742e636f6d2f6174746163686d656e742f3337343030362f365357643165726c41525378334965444346676a5a684c425a3f746f6b656e3d65794a68624763694f694a6b615849694c434a6c626d4d694f694a424d54493451304a444c5568544d6■■■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
if you want the exact BP you can download the (Demo Project v4.15: here)
if you need to create your own vector field check these tutorials
https://www.youtube.com/results?search_query=ue4+vector+field