Warp coil

Warp coils are an integral component of a starship's warp drive, which are mounted within the warp nacelles and use the plasma generated by the warp core to create the warp field that allows the starship to travel at warp speed.

In 2373, a minor adjustment to the USS Voyager's warp coils increased the efficiency of the ship's warp engines and drew the attention of an unnamed starship which took power from the ship's warp eddies. (VOY short story: "Winds of Change")