Chroniton radiation

Chroniton radiation was a by-product contaminant of the Romulan interphase generator developed in 2368. (TNG: "The Next Phase")

Chroniton torpedoes emitted chroniton radiation. Exposure to this radiation had also been associated with time travel. (VOY: "Before and After") The Orb of Time, for example, created a massive surge of chroniton radiation, when it sent the USS Defiant back in time from 2373 to 2268. (DS9: "Trials and Tribble-ations")

Miles O'Brien used chroniton radiation to expel a Pah Wraith from his wife Keiko's body. The radiation appears to kill Pah-wraiths and Prophets at a high enough level, or at least expel them from bodies they are possessing. (DS9: "The Assignment")

When Kira Nerys was willingly possessed by a Prophet on the Promenade of Deep Space 9 in 2374, it was suggested that crew flood the Promenade with chroniton radiation. Ramping up the chroniton levels slowly, the wormhole alien would be able to leave Kira's body without either getting hurt. (DS9: "The Reckoning")