why are lasers better than neutral particle beams?

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Pu-239
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Post by Pu-239 »

Can't you make a crude ion cannon by using the focused exhaust of an ion engine?

BTW if the laser is too powerful, it'll melt the mirror. Same goes for particle cannon- melts barrel.

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Post by Admiral Valdemar »

Pu-239 wrote:Can't you make a crude ion cannon by using the focused exhaust of an ion engine?

BTW if the laser is too powerful, it'll melt the mirror. Same goes for particle cannon- melts barrel.
You could do, but an EMP burst would be more effective. Ion engines now are hardly powerful unless you had a fusion reactor powering it.

As for the laser, if it is a free-electron laser then it doesn't use mirrors anyway. As for the particle beam cannons, they are protected by EM fields.
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Post by phongn »

kojikun wrote:Deuterium is an isotope of hydrogen, not a hydrogen ion.
You can ionize deuterium, however, to accelerate it. That's what AV was stating.
And if you can built a 3e25 joule particle beam, you could easilly create a gigawatt laser which would be cheaper, faster, and carries the same energy as the particle beam.
I am almost positive that a 1GW laser would deliver less energy than a 3e25 J particle beam. A whole lot less energy, over any combat-useful amount of time.
you say the beam has more energy? well if you can put that energy into the particle beam you can put it into a laser too.
Not neccesarily. There may be engineering constraints preventing you from deploying a large laser as opposed to a particle beam (or vice-versa).
And because lasers have superiority over particle beams of equal energy, a laser is better then a particle beam. Not only that, but lasers dont need ammunition.
Lasers do require a power source as well, and many designs do need ammunition.
The fact remains that if you were to fire 1 gram of particles at relativistic speeds, you can do damange, but the same energy in laser form is superior.
The effects are different, kojikun. Different weapons for different situations.
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Post by Pu-239 »

Admiral Valdemar wrote:
Pu-239 wrote:Can't you make a crude ion cannon by using the focused exhaust of an ion engine?

BTW if the laser is too powerful, it'll melt the mirror. Same goes for particle cannon- melts barrel.
You could do, but an EMP burst would be more effective. Ion engines now are hardly powerful unless you had a fusion reactor powering it.

As for the laser, if it is a free-electron laser then it doesn't use mirrors anyway. As for the particle beam cannons, they are protected by EM fields.
Can't regular reactors work? Isn't there a limit however- too much power causes the engine to wear out quickly due to the particles hitting the grid too fast?

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Post by jaeger115 »

If I recall correctly, lasers can be hampered by severe weather and clouds while a particle beam could just charge through them.
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Post by Admiral Valdemar »

jaeger115 wrote:If I recall correctly, lasers can be hampered by severe weather and clouds while a particle beam could just charge through them.
Well a particle beam would still be affected, maybe not as bad. The idea is to use a high power laser first to "drill" a hole through the atmosphere to let the particle beam through unimpeded. It would sound like a massive thunderclap as it happened in nanoseconds, the ionised air would make it look like a straight lightning bolt too and a lot of thermal and x-ray effects would be present.
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Post by jaeger115 »

Well a particle beam would still be affected, maybe not as bad. The idea is to use a high power laser first to "drill" a hole through the atmosphere to let the particle beam through unimpeded. It would sound like a massive thunderclap as it happened in nanoseconds, the ionised air would make it look like a straight lightning bolt too and a lot of thermal and x-ray effects would be present.
Cool! :D So we'd see a brilliant white beam slice through the sky with lightning bolts branching from it? I'd PAY to see that!
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Post by Pu-239 »

I think the particle beam would be affected, because of the particles being deflected by air.

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Post by Graeme Dice »

kojikun wrote: And if you can built a 3e25 joule particle beam, you could easilly create a gigawatt laser which would be cheaper, faster, and carries the same energy as the particle beam.
It wouldn't be much faster. A neutron with 50J of energy is moving at 0.977c.
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Post by Shrike »

phongn wrote:
kojikun wrote:You can ionize deuterium, however, to accelerate it. That's what AV was stating.
*cough*
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Post by Shrike »

Is there no accursed edit button? :?
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Post by Admiral Valdemar »

No, editing is not allowed for some reason.

But, yeah, it wasn't me that said that though I was going to. :)
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Post by SyntaxVorlon »

Pu-239 wrote:Can't you make a crude ion cannon by using the focused exhaust of an ion engine?

BTW if the laser is too powerful, it'll melt the mirror. Same goes for particle cannon- melts barrel.
A particle beam would not need a barrel as a laser or slug thrower does, it uses a mag field to control the heat of the plasma. A directional field cannon does roughly the same thing.
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Post by Connor MacLeod »

SyntaxVorlon wrote: A particle beam would not need a barrel as a laser or slug thrower does, it uses a mag field to control the heat of the plasma. A directional field cannon does roughly the same thing.
You need some sort of magnetic (or other if applicable) force to accelerate the particles, which may require fairly long barrels (to house the acceleration coils.)

A laser might not need a barrel though.
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Post by Connor MacLeod »

Admiral Valdemar wrote:
jaeger115 wrote:If I recall correctly, lasers can be hampered by severe weather and clouds while a particle beam could just charge through them.
Well a particle beam would still be affected, maybe not as bad. The idea is to use a high power laser first to "drill" a hole through the atmosphere to let the particle beam through unimpeded. It would sound like a massive thunderclap as it happened in nanoseconds, the ionised air would make it look like a straight lightning bolt too and a lot of thermal and x-ray effects would be present.
As I understand it, particle beams suffer worse in an atmosphere (if they're charged, the charges may ionize the surrounding atmosphere, in addition to any collsiions/repulsions that may result from passing through.)
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Post by Sea Skimmer »

Admiral Valdemar wrote:
jaeger115 wrote:If I recall correctly, lasers can be hampered by severe weather and clouds while a particle beam could just charge through them.
Well a particle beam would still be affected, maybe not as bad. The idea is to use a high power laser first to "drill" a hole through the atmosphere to let the particle beam through unimpeded. It would sound like a massive thunderclap as it happened in nanoseconds, the ionised air would make it look like a straight lightning bolt too and a lot of thermal and x-ray effects would be present.
That's what pure lasers weapons do as well. Current military lasers fire a brief low power pulse to get rid of any moister in the way, and then fire the main pulse to hit the target. Otherwise the moister will depleate the beam by reflecting it and simply being in the way.

The more humid the air, the more powerful an inital pulse you'd need. To go through a thunderstorm the inital pulse would have to be far more powerful then anything we have today, and would likely be highly effective against any target on its own. No need for the particle beam.
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Post by Connor MacLeod »

Particle beams are generally more destructive than lasers because their damage delivery mechanism differs from a laser. Lasers (IIRC) rely on "thermal coupling" - the conversion of photons into heat energy, IIRC - and alot of factors can affect this (I can't remember all of them, but they include whether the target is shiny, or dull - more reflective surfaces absorb less energy. Also, target material and wavelengths of the laser can affect thermal coupling, and significantly higher energy levels can also increase this. I can't give exact efficiency figures, but I've heard that anywhere from 30%-50% conversion efficiency is considered "good" for a laser.) Also, lasers generally also require longer "dwell" times to do their damage than a particle beam would (this isn't universal - a very energetic laser could damage as quickly as aparticle beam, one supposes). And vaporized matter at the point of contact, if sufficiently dense, can interfere with the beam and prevent it from striking the target in sustained-beam applications (called "blooming" I believe.)

Most of these problems can generally be overcome by using a high-frequency laser (X-ray laser or graser) - which are both very penetrative. But few ways exist of creating an effective X-ray laser that I know of (Free Electron laser is one way, but I dont recall any efficiencies on that - bomb pumped x-ray lasers are the other,, but of course are effectively "one shot" tricks.)

Lasers do have several advantages - for one, they don't really require the long, bulky barrels or large turrets a particle beam might (for the acceleration coils, ionization chambers, whatnot) - the optics systems can be both small and lightweight, allowing for fast tracking or targeting. Also, their velocity is not energy-dependent. They always move at c - whereas high velocities are generally applicable to larger guns (it need not neccesarily be large energy INPUTS, but particle beam velocity can be limited by the accelerator, I believe.) Of course, a laser is also going to have substantially less recoil than a particle beam, and no need to carry any "ammo" to generate said beam with. And of course, they're a bit better in an atmosphere, and aren't quite subject to the kind of scattering m ost particle beams are (mainly charged particle or plasma, whose scattering and repulsion can limit them to ranges of only a couple of thousand of kilometers, by memory.)
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Post by ClaysGhost »

Connor MacLeod wrote:Particle beams are generally more destructive than lasers because their damage delivery mechanism differs from a laser. Lasers (IIRC) rely on "thermal coupling" - the conversion of photons into heat energy, IIRC
Sufficiently powerful lasers produce such extreme electric fields that afflicted matter is almost instantly ionised, producing a propagating shock in the material.
Also, lasers generally also require longer "dwell" times to do their damage than a particle beam would (this isn't universal - a very energetic laser could damage as quickly as aparticle beam, one supposes).
In the limit of atomic-scale particles with energies like 50J , you effectively have a mass driver that operates in a beam mode. I don't think there's anything fundamental that says that lasers will require longer dwell times, though. Here, at the moment, large particle beams are simply more common than large lasers because of all the particle physics research groups wanting one, rather than lasers being inherently less effective.
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Post by Admiral Valdemar »

http://www.fas.org/spp/military/docops/ ... m#Contents

That site pretty much tells you all the pros and cons of next gen weapon systems from mirror weapons in space like Icarus in Die Another Day to orbital railguns or laser constellations and masers mounted on tanks.

It also has some nifty ideas for orbital transports etc.
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Post by phongn »

Shrike wrote:
phongn wrote:
kojikun wrote:You can ionize deuterium, however, to accelerate it. That's what AV was stating.
*cough*
::hits head on desk::
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Post by Admiral Valdemar »

phongn wrote:
Shrike wrote:
phongn wrote:*cough*
::hits head on desk::
*Keeps making phongn hit his head on desk*

Wheee!
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Post by kojikun »

But, yeah, it wasn't me that said that though I was going to.
Sorry, Psychic powers acting up again :lol:

I concede the point. Particle beams are probably better for space weapons. I would offer a concession picture, in the spirit of physics bets, but I can't think of any witty ways to work particle beams into a perverted picture :)
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Post by kojikun »

Oh, on a related note, I'm going to build a small cyclotron and try testing how well neutral particle beam weapons work on steel. :)
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Post by Admiral Valdemar »

kojikun wrote:Oh, on a related note, I'm going to build a small cyclotron and try testing how well neutral particle beam weapons work on steel. :)
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Post by kojikun »

Uh.. no exploding of the cities. o__o;
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