Isomagnetic collector

From Memory Alpha, the free Star Trek reference.

An isomagnetic collector is a type of technology which is used to reduce particle wake created by a starship's impulse engines.

In an alternate timeline the crew of Enterprise acquired the technology from the Ikaarans after having been thrown into the past. T'Pol gave herself the specifications for creating such a device in 2154. (ENT: "E²")

Judging from nomenclature of the term, this form of technology presumably utilizes magnetism.