Ok, don't flame me if the science in this is a bit screwy. I get my physics from the back of cereal boxes. But eventually you're going to run into something impossible, and I never let the facts get in the way of a good story.

The lightsaber mechanism has a tiny subatomic particle, called a meson, trapped inside it, spinning along its axis. Now a meson consists of a quark and an antiquark, superposing all three color states, bound by gluons.

Now when the thing is turned on, somehow, the meson is stretched, pulling the quark away from the antiquark, still connected by its gluons, to a distance of one meter. This is mentioned as a theoretical possibility on one of the boo...err, cereal boxes, I own. The color force prohibits the quarks from becoming separated, but *boy* does it require a lot of power. The whole shebang is still spinning along the axis of the gluons.

Now, this results in several effects:
  • The vast amount of energy put into streching the meson results in a whole lot of spontaneous particle creation near the gluon string.
  • Since the meson is spinning, it trains the newly created particles to orbit the string at a relativistic speed, lending the thing some mass
  • A tremendous amount of radiation is emitted from decaying particles and whatnot, causing the glow and enough heat to melt things.
  • The operator can somehow control whether radiation is prevalent, or the particles are. Objects striking the beam of orbiting particles are either cooked from the radiation, or flung away by virtual photons, just the way a ball is flung away from a bat hitting it.
  • In the same fashion, light striking the beam is either reflected away or absorbed by the beam.