An apparatus for generating electromagnetic radiation includes an envelope, a vortex generator configured to generate a vortexing flow of liquid along an inside surface of the envelope, first and second electrodes within the envelope configured to generate a plasma arc therebetween, and an insulative housing associated surrounding at least a portion of an electrical connection to one of the electrodes. The apparatus further includes a shielding system configured to block electromagnetic radiation emitted by the arc to prevent the electromagnetic radiation from striking all inner surfaces of the insulative housing. The apparatus further includes a cooling system configured to cool the shielding system.