Subspace jammer

A subspace jammer was a technology developed on Dubrillion in the early years of the Galactic Empire. It used an expensive parallel to the inertial compensator that could affect a broad region, and could make it impossible to use propulsion such as ion engines effectively in a given area. It was used by the Galactic Empire to cut off planets prior to the completion of the Death Star and other superweapons.

Because this technology was relatively expensive, it was eventually dropped in favor of more destructive weapons.