By 
Warp Drive Nacelles
The subspace field necessary to propel a starship across vast interstellar distances is created by a combination of the specific configuration of the starship hull and the warp field coils located in the two warp drive nacelles.
These coils generate an intense, multilayered field surrounding the ship, and it is the manipulation of this field that produces a propulsive effect.
Each nacelle contains a number of warp field coils; when energized, the coils cause an energy shift that actually changes the geometry of space around the starship.
When the coils are fired sequentially, they create warp field layers that press upon each other and cumulatively reduce the apparent mass of the vehicle, allowing the ship to move faster than the speed of light.
