Plasma stream

From Memory Alpha, the free Star Trek reference

A plasma stream is the stream of warp plasma within a warp nacelle.

In 2363, Walter Pierce killed his girlfriend Marla Finn and her lover, before throwing himself into the plasma stream of the starboard nacelle on the USS Enterprise-D, while the starship was still under construction at the Utopia Planitia Fleet Yards. Because Pierce was part-Betazoid, he left an empathic trace of the incident on the surrounding bulkheads. These traces caused Daniel Kwan to repeat his suicide in 2370, and nearly caused Deanna Troi to suffer the same fate. (TNG: "Eye of the Beholder")

The larger sex of the space-dwelling lifeforms encountered by the USS Voyager in 2371 was capable of emitting a plasma stream with a near-identical subspace signature to that of Voyager's warp nacelles. This thus caused a swarm of the smaller sex to perceive Voyager as a potential mate, and also a larger individual to challenge it. (VOY: "Elogium")