Subspace flow field
From Memory Alpha, the free Star Trek reference.
A subspace flow field is a spatial phenomenon. It is similar to a wormhole in that it emits neutrinos, ionized hydrogen, and theta-band radiation, but it does not display quantum fluctuations.
In 2373, Rislan attempted to convince B'Elanna Torres that a graviton fluctuation caused by the Nyrian translocator was a subspace flow field. She however was not fooled, after examining the spatial harmonics. (VOY: "Displaced")
