The first question is why you want to get rid of them? Although moles hunt and eat worms, they do a great deal of good breaking up and aerating and draining soil.
However, in a decorative area they can be a problem.
The most effective way is definitely to use the traps which are buried in their runs and kills them quickly.
Most of the so-called ultra-sonic and vibrating devices are not that effective and merely drive them away temporarily. Whatever you do, don't use poisons as these can be eaten by other small mammals or dogs and cats.
Personally, I'm a live and let live person, and I am sorry when people want to destroy moles. All we do is to flatten the mole hills and reseed the grassy areas.

In a field I'd leave them be - why are you wanting to get rid of?

"Anti-mole bulbs" are available. See
http://www.gardenoasis.co.uk/antimole-bulbs-p-416.html

I've seen them in the Ken Muir catalogue too.

I've heard that mole tunnels can be a danger in fields where horses' legs can collapse them - and farm vehicles too, if they are abundant.