# How could I contain plasma for use in weapons? [duplicate]

In this sci-fi world, plasma weapons are somewhat abundant in special forces, as their ammunition can be stored in smaller spaces, and in large quantities, but I ran into a problem regarding confinement:

We need a way of confinement that:

...can be created quickly.
...is capable of surviving speeds and acceleration up to 2 km/s.
...can hold plasma under higher pressures.
...is able to confine plasma with minimal losses.
...can be shaped into a bullet

Is such containment possible?

# N.S.F.A.Q:

• The intended use of this weapon is to have at least enough power to, for example, scramble or disable a random part of a Sovijet WW2 Tank, in one shot (e.g: the cannon, if struck at a sensitive point).
• The containing should last for 10 secs, max (Water bombs are contradictory, because they contain water, but are also weapons)

The More You Know!

... Randy Curry and his friends were able to fire a self-contained ring of plasma in open air, that lasted for 10 milliseconds.

• What's the intended of use of the few milligrams of plasma confined within the bullet? Maybe the same function might be achieved some other way. – AlexP May 30 '17 at 14:21
• "Containment" and "weapon" are typically contradictory. ;) – Draco18s no longer trusts SE May 30 '17 at 14:59
• Does it have to specifically contain plasma? Or can it simply generate plasma on discharge? – Chris M. May 30 '17 at 15:42
• @ChrisM No, it must contain the plasma. – Mephistopheles May 30 '17 at 15:45
• What is “NSFAQ? – JDługosz May 30 '17 at 21:17

This answer (given technological development to improve power efficiency) meets all but two of your requirements...but (potentially) bypasses their necessity. The two requirements being 'shaped into a bullet' and 'survive for 10 seconds.' This is actually a design for a true plasma weapon that fires a bolt of magnetically contained plasma.

# Yes (given technological development)

The USAF has already developed a plasma weapon that meets all but two of your requirements; but, it also bypasses their necessity.

## Project MARAUDER

Developed by Phillips Laboratory. MARAUDER was a United States Air Force experiment to develop long-range plasma weapons. It revolved around firing electromagnetically contained plasma out of a railgun encased in a toroidal (donut shaped) container. Little is known about it after 1993 because it swiftly Classified Status. We don't know if it ever went anywhere.

## Design

Their design for plasma containment is called a Compact Toroid, and their design was similar to an arrangement called a Spheromak. Basically, it looks like a donut. What's interesting about a Compact Toroid, however, is that they are capable of maintaining structural stability for a fraction of a second after release from the external magnetic fields that created it. In the case of MAURAUDER, the stability time was about $1 {\mu} s$. This was the project's biggest issue.

## Results

MARAUDER took these Compact Toroids and fired them from a railgun. Because the projectile was light-weight and magnetically strong, the prototype was able to accelerate a Compact Toroid of plasma at $10^{10}g$ (or about $98,100,000,000 m/s^2$). The resulting projectile moved at $3,000 km/s$ and struck its target with a $\approx 5$ lb TNT explosion ($5 \times 10^{-7} kT = 2.092MJ$) ---and a potent, short-range electromagnetic pulse.

MARAUDER estimated that by the year 2000, they could increase the shot velocity to $10,000km/s$. Before that could happen, MARAUDER vanished into Classified Status.

## Status

It is generally believed that MARAUDER was eventually scrapped. Because even with those insane speeds, their 'Plasma Bolt' didn't live long enough to achieve a useful range ($3,000 km/s \times 1 \mu s = 3m$).

However, in recent years, new research has shown promise in extending the lifespan of these Toroids. Some believe that we may not be far from getting containment times measured in Milliseconds ($ms$). And a plasma bolt with a lifespan of a millisecond, moving at 10,000km/s has a range of 10km. That's not bad at all. Still not quite good enough for the satellite-based weapon that MARAUDER was meant to be...but pretty solid for ground-based combat.

## Conclusion

Modern Science generally acknowledges that a donut-shape is the best shape for containing Plasma. We're still messing with the specifics of the donut (how tall is it, how wide is it, how big is the hole, how much plasma do we shove in, how hot should the plasma be, etc), but the basic consensus is that Toroids are the ideal shape for a self-sustaining plasma bolt. They work a lot like a Smoke Ring does.

Naturally, in science fiction it would be very easy to explain that scientists discovered a more stable Toroidial configuration that lasts...well...however long you need it to last for the sake of the story. And it remains grounded in science.

• You should add citations for some of the claims being made. (10^10 gs, 1 μs, etc). – KareemElashmawy May 30 '17 at 20:35
• @KareemElashmawy The vast bulk of what I said can be found in the wiki article I linked at the very start of the post. The rest can be found here: en.wikipedia.org/wiki/Shiva_Star – guildsbounty May 30 '17 at 20:41
• Yiur MathJax is formatting units as variables. – JDługosz May 30 '17 at 21:14
• @JDługosz Thanks for calling that out...that was edited in by someone else, I fixed it. – guildsbounty May 30 '17 at 21:21
• I still see them. Most don't need TeX formatting at all, if you know how to type × and µ. – JDługosz May 30 '17 at 21:24

Plasma is not necessarily hard to confine; for example, those of us who are old enough or who have an interest in the history of computing remember the beautiful Nixie tubes which were used for the displays of computers and calculators made until the 1980s or so; Nixie tubes can be ruggedized, and some have flown in space aboard Soviet (and maybe also American) spacecraft. And everybody likes the alluring neon lights which enliven nights and hide the stars.

(Picture of a Nixie tube by Hellbus. Picture of a historical neon discharge tube by Pslawinski. Both are from Wikipedia. The glowing light is emitted by plasma.)

Plasma is to be found in all gas discharge lamps while in operation; it's not magical, it is an ordinary state of matter.

Plasma requires constant electrical energy input to be maintained, so storing your plasma bullets is the biggest constraint, barring some sort of Infinite Power Supply. Other than that, you're essentially constructing bullet-sized fluorescent tubes with some sort of attached supercapacitor that can provide ionization voltages for ~10s. Glass, perhaps jacketed in something more durable like ceramic, could contain the plasma apparatus. Some handwaving of high-capacity, high-voltage, extremely compact and inexpensive supercapacitors will be needed.

To produce plasma-cutter-like effects on armored vehicles, which I assume is the goal, is slightly different, as the plasma in the above bullet won't last very long after the bullet impacts and the power source is (presumably) destroyed.

A transferred plasma cutter works by inducing a plasma in a carrier gas, which creates a very conductive path between the electrode and the "target" material, which creates a tremendous amount of heat. To recreate this in a bullet, you need:

• A small, extremely-highly-compressed canister of carrier gas
• A compact, high-voltage capacitor
• An electrode embedded inside the bullet
• A bullet design that becomes a nozzle on impact (hollow-

The idea here is that the bullet is fired not containing plasma, but everything needed to make plasma. On impact, the electrode is pushed back into the power supply and the carrier gas is released through the nozzle created on impact. The electrode strikes a plasma arc to the target, creating a conductive path and emptying the capacitor into the target. This creates your localized heat for as long as the arc can be maintained, greatly weakening or destroying the material at the point of impact.

I'm not sure if this would be able to disable a tank with a single shot, but it is scalable assuming you have this kind of super-capacitive tech. A bigger projectile yields a higher payload, so a rifle-mounted tank buster could be devised.

• Wouldn't this approach only create​ plasma for a tiny fraction of a second? More or less a tiny flash as the projectile is destroyed? – apaul May 30 '17 at 17:53
• @ apaul34208 Which approach? – Chris M. May 30 '17 at 17:54
• The approach of creating the plasma on contact – apaul May 30 '17 at 17:55
• @apaul34208 It depends on how the bullet is constructed and how "super" your supercapacitor is. But whether you store plasma inside a bullet or create it from parts of the bullet, you're not going to induce plasma for very long with a projectile. At least with the second approach, you can store your bullets normally. – Chris M. May 30 '17 at 18:00
• You'd have to get it to impact and either lightly penetrate or adhere to the surface to sustain the arc for any appreciable length of time, yes. Not to mention the fact that all the precision engineering in a plasma torch would be thrown out the window. But the OP specifically asked for "plasma contained in bullets". That's the best I could come up with, assuming he intended the plasma to cause damage. Plasma just doesn't last very long outside of carefully controlled scenarios. – Chris M. May 30 '17 at 18:15