Warp trail
A warp trail was the trail of residual subspace distortion in space left behind by the warp drive of a starship. The trail could be tracked with sensors. () The ion trails left behind by a ship traveling at warp were also sometimes referred to as warp trails. ()

If the warp signature of a ship was suppressed by remodulating its plasma injectors, the ship did not leave behind a warp trail. () A warp trail could also be masked with a randomized EM field. () A nebula could also mask warp trails. () To find and track a warp trail left behind by a tricyclic plasma drive required information on the decay rate of the plasma it used. Even when traveling at impulse the ship left behind a warp trail. () The warp drives used by Kazon-Nistrim and Rigelians ended their warp trail after the ships dropped out of warp. (; )

The ion trail left behind by a ship could be in time dispersed by stellar winds. () When an ion trail was left behind by a ship at warp, subspace distortions could be detected in its wake. () The radiation signature from the ions could be used to determine the type of craft and propulsion system that left it behind. (; ) By remodulating shield harmonics, the ion trail could be masked. () It could also be dissipated with a magneton pulse. ()

Ion trails were also left behind by other propulsion systems such as advanced ion propulsion. () Ion trails were left behind by starships and shuttles using impulse engines. It could be determined from the distribution of the ions what maneuvers the ship had used. () Federation escape pods landing on a planet also left behind an ion trail. Even after landing the propulsion system of the pod kept leaving behind the dispersion trail with a stronger concentration gradient near the pod. ()

Examples
In 2151,  followed a Suliban vessel into the atmosphere of a gas giant by tracking its warp trail. Enterprise did not originally have the sensor acuity to identify a warp trail, but this changed when Sub-Commander T'Pol modified the sensors to isolate the plasma decay rate of the Suliban ship. ()

In August of 2151, Enterprise was not able to follow the Earth Cargo Service freighter  as their long-range sensors were knocked out by the Fortunates plasma cannon and Enterprise thus could not detect any warp trail. ()

In 2152, Travis Mayweather successfully located a Kreetassan ship by scanning for their warp trail. ()

In 2153, Enterprise tracked the ion trail of an Osaarian vessel that had hidden inside a cloaking field to avoid detection. ()

In 2154, the crew of Enterprise pursued Doctor Arik Soong and his Augments into Klingon territory by tracking their warp trail. Once Soong discovered that Enterprise was using the Bird-of-Prey's warp trail to track them, he was able to successfully mask their warp trail. ()

In 2356, Magnus and Erin Hansen attempted to mask their warp trail in a nebula when they and their daughter, Annika, attempted to escape from the Borg aboard the . ()

In 2370, Chief Miles O'Brien was able to retrace a Maquis warp trail to find Gul Dukat. ()

In 2372, the crew of the  discovered the ion trail of a Kazon carrier vessel commanded by Razik which had destroy Chakotay's shuttlecraft. ()

Soon after, a warp trail was discovered leading away from a moon the Voyager crew had been surveying for polyferranide, which lead them to a seemingly lifeless planet with an unusual energy source. ()

After a raid on Voyager by the Kazon-Nistrim in which a transporter module was stolen, Seska deliberately left a warp trail behind for Captain Janeway to follow. ()

In the same year, Voyager encountered the Cardassian Dreadnought missile in the Delta Quadrant. It contained a sophisticated array of computer technology as well as its own high-powered warp drive. To avoid detection, it was also capable of masking its own warp trail. ()

A group of rogue Jem'Hadar used a magneton pulse to dissipate their ion trail after attacking Deep Space 9. ()

When the Nistrim seized Voyager at the end of 2372, Seska ordered Maje Culluh's askara to scan for the warp trail of a missing shuttlecraft even if they found its wreckage. ()

In 2373, Tieran, in the body of Kes, stole a Voyager shuttlecraft and remodulated the plasma injectors to suppress its warp signature. ()

Benjamin Sisko told Worf to look for an ion trail generated by a runabout Kira Nerys had taken to interview several Cardassians suspected of being behind the killings of a number of former members of the Shakaar resistance cell. ()

In 2377, Janeway ordered her senior staff to scan for the ion trail of Gar's ship after the Dralian stole The Doctor's program. ()

Later that year, she again gave the order to scan for ion trails after Voyagers deuterium was stolen in . ()

In 2378, The Doctor masked the s ion trail after departing with Voyagers warp core to deliver it to a pair of kidnappers. ()

See also
Impulse signature
Plasma wake
Subspace eddy
Warp eddy
Warp frequency
Warp signature

de:Ionenspur
fr:Traînée de distorsion
Warp
Subspace