I don’t doubt something will cause problems, given this is 1-20 megavolts at (for a gigawatt reactor) 50-1000 amps, but I’m not sure what issue you’re describing here. Can you elaborate?

Space charge is the accumulated effect of the charge of ions or electrons altering the electric field. It limits current flow in vacuum tubes, and also limits the current density (and hence thrust density) of ion engines.

https://en.wikipedia.org/wiki/Space_charge#Space-charge-limi...