Is an electron/proton gun possible?

In the 1944 SF story “Off the Beam” by George O. Smith, an electron gun is constructed along the length of a spaceship. In order to avoid being constrained by a net charge imbalance, it is built to also fire the same number of protons in the other direction, dissipating the mass of the “cathode”.

With current knowledge, is this plausible? That is,

  • Can a practical (i.e., not built with unobtanium insulators) electrostatic device like an electron gun separate and accelerate electrons and protons in this manner?
  • Can it actually disassemble solid matter? If so, how does the composition of the cathode affect the difficulty?


It would make far more sense to fire both streams of particles together so that you get a neutral particle beam. For starters, if the beam is uncharged it won’t disperse due to coulombic repulsion. This is basically how ion engines work.

Additional: Whilst it is sci-fi, Orion’s Arm has a fairly well thought out treatise on electron and proton beam weapons that’s well worth comparing and contrasting with the story you mentioned.

[EDIT]: I seem to have misunderstood what you meant with ‘disassemble solid matter’. As dmckee points out, all you really need to do is ionise some matter and accelerate the ions. In the simplest case, ionising hydrogen will allow you to make a proton beam. If a bulk material builds up enough charge it may disintegrate in a ‘coulombic explosion’. This is the principle behind electrospray mass spec., where you dump enough negative charge into droplets of water for them to fly apart.

Source : Link , Question Author : Kevin Reid , Answer Author : Richard Terrett

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