In Star Trek, a plasma streamer is a stream of plasma between the two stars of a binary system - most commonly, a neutron star and red giant would be connected by a plasma streamer.

Plasma streams create ionized distortion fields surrounding them, greatly reducing the efficacy of sensors, transporters, and even tractor beams. In 2369, the USS Enterprise-D was sent to the Igo system to investigate the disappearance of the USS Yosemite, a science vessel sent to remotely observe the stream. (TNG: "Realm of Fear"). Plasma streamers were also observed in the Kavis Alpha sector. (TNG: "Evolution") and the Topin system. (TNG: "Preemptive Strike") .

Descriptions and images of plasma streamers in Star Trek indicate that these phenomena were actually what are called Cataclysmic Variables (CVs). Cataclysmic Variable stars are pairs of stars that are so close together that matter is dragged away from a red dwarf or evolved star (subgiant) onto an extremely dense white dwarf star.

If the white dwarf has a strong magnetic field the material falls directly onto the north or south magnetic poles - these stars are known as polars. However, if the magnetic field is sufficiently weak, the gas forms an accretion disk around the white dwarf star before impacting onto the white dwarf.

The visual light we see originates from gas falling through the disk, and the amount of gas falling through the disk varies... cataclysmically! Gas begins to builds up in the outer disk, before falling rapidly through the disk (much like snow does on an avalanche-prone mountain). As the rate at which gas falls through the disk varies, so does its visual brightness (optically, the accretion disk outshines both stars put together). Cataclysmic variables can brighten by a factor of 100 in just 6 hours, before fading away over a week. These outbursts (avalanche) cycles can repeat over timescales of weeks to many years.

Several hundreds of cataclysmic variables are known.