Electromagnetic generator
From The Stargate Omnipedia
Large device capable which emits enormous electromagnetic currents through an incoming wormhole. Before it can begin, the generator is hoisted by a wench into position in front of the event horizon.
See also: Electromagnetic pulse.
KEY EPISODE
Redemption, Part 2 - Dr. McKay suggests the use of an electromagnetic generator to deactivate the Stargate from Anubis's super-weapon, but it only cuts the detonation time down by 24 hours and injures Major Carter.