Try, perhaps, Cannon/Pulse/EMP It won't "look" right, but it will replicate most of the function.
Those being decent range, terrible re-fire rate, and knocking out power to the things it hits.
For the rest of the "look", could try a waffleboard of Cannon/pulse/ion, and use logic shenanigans to make it fire whenever the "big" gun does.
(thus, you get a "wall" of bullets, which mostly replicate the look of the "plasma disk" seen in show.)