A plasma filament was an energetic and disruptive phenomenon found in the region of space known as "the Badlands."

In 2373, while being pursued by two Jem'Hadar fighters, Michael Eddington was able to temporarily evade the enemy vessels by plotting a spiral course around a plasma filament, thereby dissipating the warp signature of the runabout that he and Starfleet captain Benjamin Sisko were piloting. (DS9: "Blaze of Glory")