After I discovered that someone had made a handheld tesla coil (http://www.rmcybernetics.com/projects/DIY_Devices/plasma-gun.htm), I started thinking about the possibilities. For example, would it be possible to use a magnetic field(s) to control and focus the energy that is being randomly radiated from the coil? The application that I had in mind would be to focus the energy from the tesla coil along the outside of a cylindrical shaft as closely and densely as possible. Think stun baton meets lightsaber! If the shaft had an iron cored electromagnet it would only produce a circular field around the shaft that would not be sufficient to contain the energy; there would have to be a way to "compress" the field lines down as much as possible to focus the energy, not to mention to prevent being continuously x-rayed.