Impulse thruster
From Memory Alpha, the free Star Trek reference
An impulse thruster is the output manifold of an impulse-powered propulsion system. Ships known to possess impulse thrusters include Jem'Hadar fighters, Danube-class runabouts, and the Delta Flyer II. (DS9: "Rocks and Shoals", "The Assignment"; VOY: "Drive")
The impulse thrusters aboard runabouts contain one or more magnetic constrictors. (DS9: "The Assignment")
The impulse thrusters aboard a Class V planetary probe launched by USS Voyager in 2376 maintained that craft's orbit of Kelemane's planet for two hundred years before experiencing failure. (VOY: "Blink of an Eye")
