You might enjoy Lightning On Demand's Lorentz Cannon: https://www.youtube.com/watch?v=lix-vr_AF38

I does seem like a lot of stuff is needed. He's got 2 tons of capacitors in a stack 20 feet tall to get around 35 feet of range. He although he says:

"I was surprised at just how fast the plasma cannon range scaled with increasing drive voltage and how much explosive force the shock wave can deliver to target the data suggests that a plasma cannon with just a 30t high Marx Tower could achieve 1/4 mile range"

I know military contractors will have 3 or more orders of magnitude more money to throw at their technology demos, but I suspect there's some cold hard physics which shows it's totally impractical to defend anything more then very small high value targets with a system like that.