A particle beam weapon uses an ultra high energy beam of atoms
or electrons to damage a material target by hitting it, and thus
disrupting its atomic and molecular structure.
particle beam weapons are still in the early stages of
development. Nikola Tesla published the first technical description
of a charged particle beam in 1937 in an attempt to provide a
superweapon that would put an end to all war, but he was never able
to act on his plans. The main impetus for its development in recent
years was the "Star Wars" defense program of the 1980s, which has
since passed away, so the future of the device is somewhat in
question. That's not to say that particle beams aren't in use -
particle accelerators and prototype magnetic confinement fusion
reactors use them all the time. There just aren't many military
applications for them at the moment (outside of science fiction and
computer games, that is.) Still, a certain amount of research into
weaponized particle beams has been conducted, and may continue for
some time.
Particle beam weapons work by accelerating a stream of atoms or
subatomic particles to near-relativistic velocities and projecting
them in a beam. Both electrons and protons can be used to form this
beam, and would be the choice for a weapon to be used within an
atmosphere. Hydrogen atoms are the preferred choice for an
extra-atmospheric weapon - they have a neutral charge, and thus the
beam wouldn't be deflected by the earth's magnetic field, or
scattered by the mutual repulsion exhibited by charged particles.
Any type of particle beam would transfer a large amount of energy
from the beam to any object struck by it, resulting in damage from
the swift temperature increase and possibly an explosion. Think of
the effects of a lightning bolt - which is essentially a charged
particle beam - and you'll get some idea of how destructive such a
weapon could be.
