Plasma Guns

	Notice:
	Please bear with us. Your ride's still a work in progress.

Our most iconic science fiction works feature improbably attractive heroes and heroines wielding blaster guns that shoot out energized glowing bolts that zip along at speeds that can be visibly tracked by eye and explode when they hit something. These bolts are often popularly supposed to be made of a state of matter called plasma. Sometimes this is even supported in the show's lore and on-screen terminology. But how realistic are these? Can plasma weapons really even exist?

What is plasma

Plasma is a state of matter where the atoms are not bound to each other and can move freely, and the electrons are not bound to the atoms. Compare this to a gas, which is a state of matter where the atoms are not bound to each other but where the atoms are also electrically neutral. So, to a first approximation, a plasma is simply a gas with some additional electric and magnetic properties by way of having free charges that can transmit electric currents.

You can also compare this to a metal, which is a state of matter where the atoms are bound to each other, either as a solid (like copper) or a liquid (like mercury), but the electrons are free to move. So a plasma will behave something like a metal and something like a gas. But the particular emergent properties you get from both being able to flow and to conduct electricity give it a nature all of its own.

The physics of plasmas can get quite involved. However, for the purpose of this article, we can ask ourselves how much a plasma can deviate from gas-like behavior? This is constrained by the virial theorem, which shows that any localized configuration of fields, charges, and currents cannot hold itself together by any self-forces. It will dynamically expand until it is constrained by external forces.

Terminology: A localized "blob" of plasma is called a plasmoid

Stuff to do

Non-virialized plasmas – neutral particle beams

Producing your plasma at the target (lasers, bombs, hypervelocity kinetics, nuclear explosives)

Visual similarity (tracers and gyrojets)

What about ball lightning