Originally Posted by American Maid
Well, she does research on Einstein-Rosen bridges and certain anomalies that brought her to the New Mexico desert in the first film. The Foster Theory has something to do with the structure of Yggdrasil and how Einstein-Rosen bridges form interconnections therein.
I would assume the gadget allows her to take measurements when she is in the vicinity of some portal opening, or when she is observing some similar phenomenon. What few stills I am able to find of her equipment in Thor1 do not show anything bearing any resemblance to this device. But it could well be that this prop was indeed used in that film and no one posted a picture.
It also doesn't look like the device in the alternate ending that makes the image of Yggdrasil and shoots the beam into space.
Yeah, I'd be willing to bet it's some sort of wormhole warning system, or maybe even Foster and/or Selvig's research has gone so far as to allow them to create/manipulate the wormholes now themselves....?
Plot-wise, I'd guess that her Gizmospaztransmogrification Device went off when Thor made his way to London, and now, in this scene, it's gone off again because Malekith just showed up uninvited.