AT: "xx" A broad-spectrum warp field, also known as an inverse warp field, is an energy emission used to keep a starship stationary in space. It can be created by specially-modified warp engines.
In 2370, an alternate quantum reality-counterpart of Lieutenant Commander Data was able to determine that, by piloting a shuttle into a quantum fissure and initiating such a warp field, Lieutenant Worf would be able to seal the fissure and return to his own universe, as he had been uncontrollably shifting to different realities as a result of an encounter with the fissure. (TNG: "Parallels")
Creating an inverse warp field was also analogous to dropping the anchor for a starship. USS Voyager used such a field in 2376 in an attempt to ride out a massive neutronic wavefront impacting it's shields at a velocity of 200,000 kilometers per second. The warp core needed to be converted before the field could be generated. (VOY: "Fair Haven")