A magnetic field will move charged particles, but, unfortunately, will also draw them towards the ship at the poles. Lasers are also a no-go as, even if the photons could somehow get through the warp bubble, your ship is moving faster than they are and they'd just collect at the edge of the bubble. The same problem applies to anything else originating from the ship, really. Unless we can figure out some sort of anti-gravity projector to push the particles out of the way ahead of the bubble, I don't think there's a viable solution.
Centrifugal force? If the warp bubble is spinning on the ship's axis, it would capture the particles, but push them out to the side.
The nifty thing about an Alcubierre drive is that the interior is causally separated from the exterior, you don't need to deflect dangerous particles, they can't pass through the bubble to threaten the ship. The threat they pose is anything caught in the bubble being released when the bubble is dispersed. They wouldn't threaten the ship, but anything ahead of the ship.
I find this to be to quick to say the is a down side with warp drive so quickly since they have not even invented and test the technology yet. Sure if this is what they think may happened fine but I hope this will not stop them from at least trying. Surely cant they just drop at of warp before the ship get very close to its destination and do the rest of the trip with its sublight engines. Obviously they should continue to do more research and see where it really leads them. What about a collector which can collect the extra energy and put it to use?