Plasma weapon, why it will not work

His Divine Shadow · Post by **His Divine Shadow** » 2004-05-11 08:20am

http://www.schlockmercenary.com/chalain-vasimr.html

This article was once used on SB as an example of how a plasma weapon could work, but I doubt it, problem is I dunno why beyond that releasing the hot plasma will simply not work because it'll dissipate too quickly, anyway it sounded quite fascinating but I'd like to know whats wrong with this article, if anything.

Admiral Valdemar · Post by **Admiral Valdemar** » 2004-05-11 08:49am

Without containment, you don't need any other argument to show the weapons as useless. Lasers and particle beams would be far better or simple KE weapons anyway.

Metrion Cascade · Post by **Metrion Cascade** » 2004-05-11 09:04am

What about some kind of bomb or shell containing plasma?

Shroom Man 777 · Post by **Shroom Man 777** » 2004-05-11 09:25am

Well, won't a particle weapon be considered as a plasma weapon of some sort?

The Nomad · Post by **The Nomad** » 2004-05-11 09:48am

Shroom Man 777 wrote:Well, won't a particle weapon be considered as a plasma weapon of some sort?

Not necessarily, though a plasma beam is a kind of particle beam.

A plasma, by its simplest-sounding definition, is a collection of free charges. If the charges in the beam are freely moving ( but the beam is overall neutral ), it is a plasma beam. If there is only one type of charge, it's an electron/positron/(antiàproton/ion ( or whatever charged particle ) beam.

Though I suspect my definition of 'plasma' is not quite the same that is used in Sci-Fi ( aka superheated ionized gas...

).

To put it simply : a 'plasma weapon' won't work because the plasma will expand and therefore cool down ( the perfect gases law works for plasmas, right ? ). Magical containment fields are a brainbug - ask them references to peer-reviewed publications dealing with such kinds of wanktech

...

Come to think about it : the free electrons in a metal are technically a plasma, right ? So a knife, sword or average bullet contains plasma, if you see my point...

Post by **Darth Wong** » 2004-05-11 10:23am

The Nomad wrote:A plasma, by its simplest-sounding definition, is a collection of free charges. If the charges in the beam are freely moving ( but the beam is overall neutral ), it is a plasma beam. If there is only one type of charge, it's an electron/positron/(antiàproton/ion ( or whatever charged particle ) beam.

Though I suspect my definition of 'plasma' is not quite the same that is used in Sci-Fi ( aka superheated ionized gas... ).

To put it simply : a 'plasma weapon' won't work because the plasma will expand and therefore cool down ( the perfect gases law works for plasmas, right ? ). Magical containment fields are a brainbug - ask them references to peer-reviewed publications dealing with such kinds of wanktech ...

Come to think about it : the free electrons in a metal are technically a plasma, right ? So a knife, sword or average bullet contains plasma, if you see my point...

Where did you get that definition from? Plasma is ionized gas, not any moving charge. Ionization is part of the physics definition of plasma.

Anyway, the linked article describes a plasma rocket of sorts, not a plasma weapon. I've been tinkering with a partially finished article on plasma weapons at http://www.stardestroyer.net/Empire/Ess ... apons.html but I haven't had time to double-check the math and all the data yet.

Sarevok · Post by **Sarevok** » 2004-05-11 11:34am

Metrion Cascade wrote:What about some kind of bomb or shell containing plasma?

Conventional bombs or shells cant contain plasma becuase they would melt in the extreme heat Containing plasma requires huge amounts electrical power to generate the strong magnetic fields that contains them. A shell containing plasma would be extremely heavy due to the weight iof the power source. And it would probobly do less damage than a conventional shell of same mass.

Shroom Man 777 · Post by **Shroom Man 777** » 2004-05-11 11:45am

So if the beam travels at relativistic speeds, whatever that is, then all is well?

What is relativistic speed? Something akin to the speed of light?

Sarevok · Post by **Sarevok** » 2004-05-11 11:52am

Relativistic speed is close to the speed of light where effects predicted by Einstein become detectable.

SirNitram · Post by **SirNitram** » 2004-05-11 12:29pm

Just two things, probably worthless:

The idea that SW weapons are plasma come from the Original Trilogy Visual Dictionary's and Incredible Cross-Sections, IIRC. Definately in the VD.

At one point you talk about plasma weapons not falling due to gravity, and a little later you talk about them having to rise due to bouyancy. This scans a little oddly, but having not the knowledge of bouyancy mechanics, I can't check if they should be cancelling each other out.

McC · Post by **McC** » 2004-05-11 12:32pm

Darth Wong wrote:Anyway, the linked article describes a plasma rocket of sorts, not a plasma weapon. I've been tinkering with a partially finished article on plasma weapons at http://www.stardestroyer.net/Empire/Ess ... apons.html but I haven't had time to double-check the math and all the data yet.

That's a good read, Mike. Very insightful and educational.

Warspite · Post by **Warspite** » 2004-05-11 01:03pm

SirNitram wrote:At one point you talk about plasma weapons not falling due to gravity, and a little later you talk about them having to rise due to bouyancy. This scans a little oddly, but having not the knowledge of bouyancy mechanics, I can't check if they should be cancelling each other out.

Think about a hot air baloon, it's the same mechanism, substitute the hot air for plasma and it behaves in the same manner. (In extremis, plasma is hot air, no?)

Mike, good article, but you forget to mention the common misconception of using "rifling" to stabilize a plasma, without (or, in addition to) the magic containment field.

SirNitram · Post by **SirNitram** » 2004-05-11 01:05pm

Warspite wrote:
SirNitram wrote:At one point you talk about plasma weapons not falling due to gravity, and a little later you talk about them having to rise due to bouyancy. This scans a little oddly, but having not the knowledge of bouyancy mechanics, I can't check if they should be cancelling each other out.
Think about a hot air baloon, it's the same mechanism, substitute the hot air for plasma and it behaves in the same manner. (In extremis, plasma is hot air, no?)

Right, it can be made to acheive a 'Neutral' state. Which, if you are using plasma weapons for some reason, is a good idea, since it massively extends your weapons range, because the projectile won't drop.

The Nomad · Post by **The Nomad** » 2004-05-11 01:14pm

Darth Wong wrote: Where did you get that definition from? Plasma is ionized gas, not any moving charge. Ionization is part of the physics definition of plasma.

Well, I was taught that plasma was often a gas, but not always. Hence the mention of the electron in a metal ( unless you talk about an 'electron gas' in English - I know that this expression exists in French, but as far as English is concerned I don't know if it is accurate... ).

Perhaps it is the word 'free' that is innacurate : I meant that the charges are not bound together ( my apologies for being so vague, but I was only very briefly introduced to plasma physics more than six months ago and never told about since, and if that wasn't enough, my English has been far from improving

)

Merriam-Webster online wrote:4 : a collection of charged particles (as in the atmospheres of stars or in a metal) containing about equal numbers of positive ions and electrons and exhibiting some properties of a gas but differing from a gas in being a good conductor of electricity and in being affected by a magnetic field

I was probably focusing on the first part of the definition, which was closer to what I remembered... nevermind.

Excellent article, by the way.

The Nomad wrote:If the charges in the beam are freely moving ( but the beam is overall neutral ), it is a plasma beam. If there is only one type of charge, it's an electron/positron/(antiàproton/ion ( or whatever charged particle ) beam.
...
and therefore cool down ( the perfect gases law works for plasmas, right ? )

Please forget those parts.

Korvan · Post by **Korvan** » 2004-05-11 01:14pm

The Zot-Fot-Pik in Star Control 2 had a viable plasma weapon. Their special attack involved grappling with the enemy ship and injecting reactor plasma into said ship via a proboscis. In the game, it was one of the most damaging attacks, but difficult to carry out.

The Nomad · Post by **The Nomad** » 2004-05-11 01:17pm

The Nomad wrote: If the charges in the beam are freely moving ( but the beam is overall neutral ),

Upon re-reading my post more carefully, it appears that it is this part ( the 'freely moving' ) that's inaccurate : I wasn't in fact thinking of the charges freely moving within the beam, but of the particles moving overall as a beam ( my post was confusing eitherway - my apologies again

)...

1337n1nj4 · Post by **1337n1nj4** » 2004-05-11 01:28pm

Couldn't a pure-fusion warhead of sufficient yield be considered a "plasma bomb" of sorts? I mean, that's basically all the fireball is, and if said fireball lasts for a given amount of time (intentionally or otherwise), that'd be your boy right there.

'course, that would be limited to planet-side usage.

His Divine Shadow · Post by **His Divine Shadow** » 2004-05-11 01:28pm

SirNitram wrote:At one point you talk about plasma weapons not falling due to gravity, and a little later you talk about them having to rise due to bouyancy. This scans a little oddly, but having not the knowledge of bouyancy mechanics, I can't check if they should be cancelling each other out.

Well at first he's talking about a plasma weapon with low-density composition, this type will float because it's less dense than air.
The falling effect occurs when he moves on to the idea of compressing it into the size of a bullet in order to try and bypass some problems.

SirNitram · Post by **SirNitram** » 2004-05-11 01:29pm

His Divine Shadow wrote:
SirNitram wrote:At one point you talk about plasma weapons not falling due to gravity, and a little later you talk about them having to rise due to bouyancy. This scans a little oddly, but having not the knowledge of bouyancy mechanics, I can't check if they should be cancelling each other out.
Well at first he's talking about a plasma weapon with low-density composition, this type will float because it's less dense than air.
The falling effect occurs when he moves on to the idea of compressing it into the size of a bullet in order to try and bypass some problems.

True. Oh well, it was worth a few neuron firings.

1337n1nj4 · Post by **1337n1nj4** » 2004-05-11 01:37pm

His Divine Shadow wrote:
SirNitram wrote:At one point you talk about plasma weapons not falling due to gravity, and a little later you talk about them having to rise due to bouyancy. This scans a little oddly, but having not the knowledge of bouyancy mechanics, I can't check if they should be cancelling each other out.
Well at first he's talking about a plasma weapon with low-density composition, this type will float because it's less dense than air.
The falling effect occurs when he moves on to the idea of compressing it into the size of a bullet in order to try and bypass some problems.

You know....under the right circumstances, and with some handwavium thrown in for effect, that buoyancy effect might be exploited as a nifty AA weapon.

Or maybe not. The whole thing just sounds unfeasible.

Admiral Valdemar · Post by **Admiral Valdemar** » 2004-05-11 02:59pm

Technically, a HEAT anti-tank round is a plasma weapon or as close to it as we can get today (and they have existed for decades).

Hydrogen bombs are plasma bombs and charged or neutral particle beams could be considered plasma weapons in a way.

Plasma does NOT have to be hot by definition, there are plenty of plasmas that are at room temp.

Ender · Post by **Ender** » 2004-05-11 03:06pm

http://www.globalsecurity.org/military/ ... nd/pep.htm

US Army's use of a plasma weapon. Judging by the description, I can't tell if the plasma is actually fired towards the target first and the shockwave happens when the plasma gets close, or if it happens in the weapon itself and the shockwave is directed.

And Mike, what about using a low energy laser to cause thermal bloom and clear out the atmosphere ahead of the plasma?

SWPIGWANG · Post by **SWPIGWANG** » 2004-05-11 03:15pm

You still need magical containment force field even if you clear away the air. Hell, the amount of energy required to make the idea pratical would make a useful laser weapon in itself......

Warspite · Post by **Warspite** » 2004-05-11 05:55pm

Admiral Valdemar wrote:Technically, a HEAT anti-tank round is a plasma weapon or as close to it as we can get today (and they have existed for decades).

It's not because the copper "slug" is in a gellified state, it doesn't achieve a plasma state... The detonation only liquifies a part of the material, and it doesn't manages to sublime it into a gas.

Admiral Valdemar · Post by **Admiral Valdemar** » 2004-05-11 06:23pm

Warspite wrote:
Admiral Valdemar wrote:Technically, a HEAT anti-tank round is a plasma weapon or as close to it as we can get today (and they have existed for decades).
It's not because the copper "slug" is in a gellified state, it doesn't achieve a plasma state... The detonation only liquifies a part of the material, and it doesn't manages to sublime it into a gas.

The term "metal plasma" is used instead of the usual gas plasma. As I said, it's the closest to a plasma weapon we have in active conventional service right now until the PEP is brought in.