Thermionic radiation
Thermionic radiation is a form of energetic radiation.

The atmospheres of Y-class planets emitted discharges of thermionic radiation that could pose a threat to starships in orbit. () 

Thermionic radiation is harmful to lifeforms, but dissipates relatively quickly. In 2375, Captain Rudolph Ransom claimed that the 's research lab was inaccessible due to thermionic radiation. Seven of Nine later discovered that the radiation was being deliberately maintained by three EPS conduits to keep the  crew from discovering their exploitation of nucleogenic lifeforms. ()

de: Thermionische Strahlung
Radiation