Jump gate

A vortex forms in a jump gate.

A jump gate is device that creates a vortex into hyperspace to provide ships that lack their own jump engines with a means of interstellar travel.

John Sheridan once used a jump gate as an improvised weapon to destroy a Shadow ship. With the vortex in the jump gate still open, he used the hyperdrive on his own ship -- the White Star -- to open another vortex inside the first one. This event created a massive explosion as all of the energy being used to maintain both vortexes was released at once. The actual amount of energy released by the explosion is not known, but it was sufficient to destroy the pursuing Shadow ship, and the White Star was almost unable to escape at maximum acceleration.