Unlike most modern electronic weapons, the functionality of fully-mechanical rifles are complemented by their durability. They can be used without authorization, electricity, or calamity-proofing.

However, plasma weapons are a different topic.

Gas magazines are easily contained, or harvested. You just need a pressurized tank with a trigger-controlled valve.

But, ionizing them into plasma, and then firing that plasma with electromagnets, more or less requires electricity, and electricity requires a battery, or at least an energy buffer, to be portable.

Everything that works with electricity is in danger of not working properly in presence of an EMP, lack of insulation, or lack of power source.

So, here goes.

What mechanism should a plasma rifle have for it to still work when there's a storm, when underwater, or when an EMP bomb is detonated?

  • $\begingroup$ Powered down and shielded electronics supposed to survive even the strongest EMP shock. Would that be sufficient for you? $\endgroup$ – Alexander Sep 26 '18 at 20:15
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    $\begingroup$ Plasma underwater? I don´t think it may be possible: Either Plasma would boil the water, or the water would cool the plasma, or else the plasma would occur only within a bubble. I recommend you to take a look at this article: scienceline.ucsb.edu/getkey.php?key=1690 $\endgroup$ – Carlos Zamora Sep 26 '18 at 20:18
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    $\begingroup$ Hello Kyle. Can you simplify this question by removing anything not related to your primary topic (electricity)? The mechanics for firing an electrical weapon underwater are very different from the mechanics needed to avoid an EMP. And discharging a plasma weapon underwater isn't sensible (unless you intended suicide) as the water immediately surrounding the weapon (and you) would instantly superheat in an expanding bubble. Bad. Very bad. $\endgroup$ – JBH Sep 26 '18 at 20:45
  • $\begingroup$ None? Plasma can't really exist underwater, there is no purely mechanical way to heat things so fast, in so small casing, and so on. $\endgroup$ – Mołot Sep 26 '18 at 21:21

Plasma can be created without electricity, it's just generally a lot harder any other way so we normally don't do it. What you need is a large concentration of energy applied to a relatively small number of particles in a short amount of time.

One way to do this is with a laser. Some research has been done on this to create a Plasma Channel along the path of a laser. Again normally most lasers are powered by electricity, but they can be powered directly by chemical reactions, requiring no electricity. Chemical lasers could be fired into a chamber in the rifle containing a gas to ionize it into plasma.

So your plasma weapon would need three tanks, two for the chemicals to mix to power your laser, and a third to supply the ionizing gas to produce the plasma.

After forming the plasma will want to expand rapidly and could most easily be directly vented to make an impressive short range plasma cutter type weapon. And based on how the process works it could be continuously fired by providing a continuous flow of chemical reactants.

For a longer range weapon, you need the magnetic field to confine and propel your plasma. This is likely only possible with electromagnets, but could be powered by the plasma itself and only be energized while firing, not requiring any electronics or batteries.

Oh and no plasma weapon will work underwater. You would get a large steam bubble exploding in all directions (including backwards at you), when the plasma hit the water at the barrel of your gun.


It should be possible to derive the energy from a purely mechanical source, the trick is that you need to convert it into electricity first. Now depending on how hard you can handwave the efficiency of the conversion; you have a variety of options:

Typical chemical cartridge: Gunpowder or possible a longer burning solid fuel (more like a model rocket engine) that can produce hot pressurized gas. Conventional turbine conversion for electricity.

Coiled Springs: Imagine a tape measure and how it tries to "wind back up" when you let go. Same type of thing in a case or box that can be loaded into your weapon; however in this case it's already got potential energy cranked into it. The trigger releases this lock and you convert the kinetic to electric.

Engines: Literally a generator, your "ammo" is fuel for the engine. Think something like a sci-fi plasma leaf blower.


Using it underwater seems impossible as others have stated, but having it work after being completely submerged shouldn't be an issue.

Wrap your gun in a Faraday cage

If your electronics are hidden away inside a suitable Faraday cage, an EMP shouldn't interfere with them. Though the cage itself might be charged up and problematic, but the gun itself should work if you can pull the trigger.

Use a generator directly

You already state that you're using gas magazines, and this can be used as fuel for a more or less purely mechanical engine that power your components directly. Igniting the gas can be done by a spark created by mechanical means.


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