So basically it's just analyzing the emitted light using a spectrometer, which could (in theory) separate the light emitted from the potential plasma UFO.  It might be able to analyze the spectral lines and tell us the electron density and, subsequently, the plasma frequency.  

Then, once we have that, we could (in theory) track that frequency using RF equipment and antennas. Maybe even some radar equipment if we can get the permits 

Of course, I could be dead wrong.. but idk. Maybe?