The energy weapon of Asgard design is a round device approximately four feet in diameter. When activated, it fires a brilliant white directed energy pulse. The device was used to correct the space-time rift when an SG-1 team from an alternate universe entered our reality by opening a wormhole through a black hole and causing a rupture in the space-time continuum that led to a ripple effect of multiple SG teams arriving through the gate from many different realities. By opening a wormhole through the black hole to the original point of origin at P7X-455 and firing a directed energy pulse through the stargate, SG-1 was able to reverse the space-time rupture and invert the convergence effect that had drawn the alternate teams into our universe. The plan worked, and the alternate teams were returned to their own realities. The energy weapon was only on loan to the SGC, however, and Kvasir insisted that it must be returned to the Asgard when the procedure was completed.
Cross Reference: Alternate Reality - Ripple Effect, Asgard, Kvasir
Episode Reference: Ripple Effect