Confinement rings

Confinement rings were a fictional type of force field within The Adventures of Captain Proton holoprogram. They were located in the Fortress of Doom and used by Doctor Chaotica to immobilize intruders.

Chaotica did just that to Kathryn Janeway, who was playing the part of Queen Arachnia within the program, when she attempted to take control of his death ray.