There are no dumb questions, only dumb answers - so here goes:

Hot things emit light. The wavelength(s) of light a substance emits depends on the temperature of that substance - cooler things emit longer (redder) wavelengths, hotter things are bluer. If the substance is cool enough, the light emitted will be mostly or wholly infra-red, therefore invisible to the naked eye but still detectable. The top of a flame is like that - the gas is still hot but no longer glowing visibly as it cools. Therefore the answer to your question depends on how hot the plasma is, but a confounding factor is that the hoovering object would create friction in the incoming material, thereby heating it up. I think the corona of a star glows with its own light (not just light emitted by the core), so I expect therefore that you would see a lot of light overall, especially nearer to whatever is doing the vacuuming.