"Pulse" and "Phased" Weapons

[Battlehymn Republic]

Do the adjectives "pulse" and "phased" weapons in sci-fi (as in lasers and particle beams) mean anything? Or are they usually just technobabble? What are the exceptions?

[Hotfoot]

Quite often (especially in star trek), it's technobabble. Lasers are almost always pulsed and "in phase" by their natural operation method. It's like referring to an EMP weapon as an "EMP Pulse", but only slightly less annoying.

Don't know as much about particle beams, however. I imagine one that is in phase would be a curiousity.

[Ariphaos]

A pulse gun might be a repeating laser cannon or similar to allow the components to cool, try to take advantage of resonant frequencies in poorly built armor, or merely that it is a scaled down, single-blast version of a larger, continuous-firing weapon. A PPB might be a Pulse Particle Beam gun, for example, because for one reason or another it can't or won't put out an extended stream.

Regarding light and electricity, phase has meaning, in the case of electricity for example, your house gets two wires of three-phase alternating current power, because it is more efficient to transmit power that way. Some industrial machines require all three 'lines' of this system, because they're cheaper to build (I forget the exact reason).

IIRC phase in light has to do with polarity. Some creatures see polarity instead of color (octopus, etc), especially underwater in order to determine what is sunlight and what is reflected. I don't know how lasers affect polarity or why it would matter. Perhaps Star Trek shields are ultra-efficient at polarity setups that end up crossing 'zero' or something.

[Braedley]

Regarding light and electricity, phase has meaning, in the case of electricity for example, your house gets two wires of three-phase alternating current power, because it is more efficient to transmit power that way. Some industrial machines require all three 'lines' of this system, because they're cheaper to build (I forget the exact reason).

No, no, no. If your house gets a 3 phase supply, either 3 or 4 wires enter your home (depending on the conductivity of the ground, we won't go into this). Some home appliances use 3 phase power (clothes wahser and dryer for exapmle), so it's not limited to industry. 3 phase is not necessarily more efficient to transmit. Some 3 phase machines aren't cheaper to build, but when you need 3 phase for something else, a machine that's more expensive to build may be much cheaper to run. I have only started to deal with 3 phase power in my courses, and I don't plan on entering that area of electrical engineering, but I know what you're saying isn't totally correct.

Now, back on topic. A pulsed weapon sends out pulses of energy, much like a machine gun sends out discrete bullets, not a solid stream of lead. My guess (and it is only a guess) is that phased weapons somehow alter the phase between the electric and magnetic components of an electromagnetic wave.

[Darth Wong]

"Phased" is a totally meaningless concept in sci-fi. They use it almost as a magic word. In real-life, it just means that you've got something which is phase-coherent: that's something you can say about lasers, electrical wiring, and even a standing audio wave from the subwoofer in your living room.

[Ariphaos]

No, no, no. If your house gets a 3 phase supply, either 3 or 4 wires enter your home (depending on the conductivity of the ground, we won't go into this). Some home appliances use 3 phase power (clothes wahser and dryer for exapmle), so it's not limited to industry. 3 phase is not necessarily more efficient to transmit. Some 3 phase machines aren't cheaper to build, but when you need 3 phase for something else, a machine that's more expensive to build may be much cheaper to run. I have only started to deal with 3 phase power in my courses, and I don't plan on entering that area of electrical engineering, but I know what you're saying isn't totally correct.

Uhh, four wires enter your home.

Two of them are power. 'Black' or 'Hot' wires. If you open up your circuit panel at home and pry off the covering, you might be able to see it depending on how your wiring is laid out.

One is return / neutral. The white wire. It's actually the sum of all three phases.

One is ground. Bare wire.

Your washing machine, dryer, and probably air conditioner run on two phases, not three. You should know that already if you're in such a course, or maybe they haven't quite gotten to the math yet.

Other houses on your block will get a different set of the three power wires, to hopefully balance out the load.

Transmitting a single phase or DC current over extreme distances -is- inefficient. That's why it's sent out from the power station as three-phase power - because it all adds up to zero (neutral).

-----

Doing some more lookup on my basic electrics, phases and all that, a single phased beam is meaningless technobabble. Two lasers that are phase coherent with eachother can have a meaningful effect by generating an effective current between them on a target. However it's not possible to have a single beam be 'phase coherent' - it explicitely refers to the continual difference in signal strength between two charges.

[drachefly]

"Phased" is a totally meaningless concept in sci-fi. They use it almost as a magic word. In real-life, it just means that you've got something which is phase-coherent: that's something you can say about lasers, electrical wiring, and even a standing audio wave from the subwoofer in your living room.

Achieving a phase-match in real life can have dramatic effects -- the reason it's commonly used it because it's useful. So it's reasonable that it would continue to be useful in the future. However, in ST it tended to get applied to things for which the concept is meaningless. ::

[Ariphaos]

Achieving a phase-match in real life can have dramatic effects -- the reason it's commonly used it because it's useful. So it's reasonable that it would continue to be useful in the future. However, in ST it tended to get applied to things for which the concept is meaningless. ::

Notice, though, that in TOS the ship's main phaser banks were two separate beams. If those were phase coherent with eachother, they could generate a pretty powerful effect on the area between them on a target.

[kheegster]

IIRC phase in light has to do with polarity. Some creatures see polarity instead of color (octopus, etc), especially underwater in order to determine what is sunlight and what is reflected. I don't know how lasers affect polarity or why it would matter. Perhaps Star Trek shields are ultra-efficient at polarity setups that end up crossing 'zero' or something.

Phases in light are separate from polarity, but refer to how 'out of step' the wavelengths of the individual photons are. So in lasers, the term 'being in phases' means that all the photons are in phase.

Polarity, on the other hand, refers to the inclination of the electric/magnetic fields that makes up light.

[Darth Wong]

Achieving a phase-match in real life can have dramatic effects -- the reason it's commonly used it because it's useful. So it's reasonable that it would continue to be useful in the future. However, in ST it tended to get applied to things for which the concept is meaningless. ::

Notice, though, that in TOS the ship's main phaser banks were two separate beams. If those were phase coherent with eachother, they could generate a pretty powerful effect on the area between them on a target.

No they couldn't, because the total power of the two beams cannot exceed their raw mathematical sum. 1 + 1 = 2, even if the two "1"'s are phase-coherent.

[Admiral Valdemar]

The only problem with The Terminator ones is that plasma is a somewhat less accurate term. It's obviously a particle beam weapon, since plasma is a brainbug of sci-fi and would be useless unless the particles were phased via an EM field and projected at a good fraction of c. That, and Ah-nuld saying "40 Watt range" in the movie. I'm thinking big goof, unless SKYNET managed to make 40 Watts vape humans through sheer intellect.

In reality, "pulse" has a special meaning with lasers. You get continuous wave lasers like in your CD player. For military concerns, a CW laser is inefficient, unless you can keep it on target for seconds. Pulsed beams are far better, giving out the energy froma capacitor in a microsecond and doing so continuously for a continuous beam like effect if fired successfully. Particle beams are the same.

[Ariphaos]

No they couldn't, because the total power of the two beams cannot exceed their raw mathematical sum. 1 + 1 = 2, even if the two "1"'s are phase-coherent.

Considering that this type of technology has actually been developed and been in use since the electric grid got laid down in the US... Thinking of it like 1 + 1 = 2 is going to get you nowhere. I'll draw the pictures and do the math if you want, but to summerize -

For example, it's how your dryer works. Rather than using neutral and a hot wire, it uses the power difference between both hot wires. The two hot wires are phase coherent with eachother, each supplying ~117 RMS voltage, but since they are 120 degrees out of phase with eachother, they supply roughly 220 volts of power, instead of 230.

If you have two phase coherent beams striking a surface, and they are 180 degrees out of sync from eachother, then they will generate a current between them with roughly the same amplitude (on a superconducting surface...). This third waveform is the actualy phase coherent 'beam', as it represents the difference in potential between the two beams. That is, that energy is there, it's real, it's just a cheaper way of transporting it.

Such devices have actually been designed, and in theory they would work like tasers, but since the atmosphere tends to conduct at the necessary voltages, their range is doomed to be extremely short.

[Darth Wong]

No they couldn't, because the total power of the two beams cannot exceed their raw mathematical sum. 1 + 1 = 2, even if the two "1"'s are phase-coherent.

Considering that this type of technology has actually been developed and been in use since the electric grid got laid down in the US... Thinking of it like 1 + 1 = 2 is going to get you nowhere. I'll draw the pictures and do the math if you want, but to summerize -

For example, it's how your dryer works. Rather than using neutral and a hot wire, it uses the power difference between both hot wires. The two hot wires are phase coherent with eachother, each supplying ~117 RMS voltage, but since they are 120 degrees out of phase with eachother, they supply roughly 220 volts of power, instead of 230.

If you have two phase coherent beams striking a surface, and they are 180 degrees out of sync from eachother, then they will generate a current between them with roughly the same amplitude (on a superconducting surface...). This third waveform is the actualy phase coherent 'beam', as it represents the difference in potential between the two beams. That is, that energy is there, it's real, it's just a cheaper way of transporting it.

Such devices have actually been designed, and in theory they would work like tasers, but since the atmosphere tends to conduct at the necessary voltages, their range is doomed to be extremely short.

Have you got a problem with math? The point remains: the power of two phase-coherent beams will not exceed their mathematical sum.

[Ariphaos]

Have you got a problem with math? The point remains: the power of two phase-coherent beams will not exceed their mathematical sum.

I think I'm doing a poor job of explaining. When a single laser beam hits a target, its energy will normally be entirely dispersed as heat into the target (ignoring albedo for a moment), because the excited electrons aren't going to go anywhere in particular.

Say though, you have two lasers and they are firing in 180 degree phase coherence. You then begin to cause a flux between the points of impact, and the energy that would normally evenly dissipate into the target at the target points instead creates a current between them.

If you want to think of pure electricity, two wires, 180 degrees out of phase, crossing a light bulb will generate an alternating current twice as strong as a single wire going to ground. No additional energy is being created, it's just being directed in a different manner than you are normally used to.

That better?

[Wyrm]

<snip some laser thing>

Dude, is this laser thing a real life, physical effect your talking about? If so, I think it's time for some references.

[Braedley]

<snip some laser thing>

Dude, is this laser thing a real life, physical effect your talking about? If so, I think it's time for some references.

Actually, I think it's time to reference everything you've said in this thread. Also, maybe some credentials?

[Ariphaos]

Dude, is this laser thing a real life, physical effect your talking about? If so, I think it's time for some references.

Well I can find an article about a spin-polarized current being generated using a double-photon 1.55 um laser and a single-photon 775 nm laser, but the article itself costs $30 so I can't see how far apart those beams are.

http://www.iop.org/EJ/abstract/0268-1242/19/4/075

They can't be too far, and they can't be too close otherwise they would phase lock. Incidentally, is another way of creating a 'pulsed' laser weapon - by bringing two laser waveforms close enough together to phase lock, you can create a nonstandard waveform and transmit high-energies in short periods in a 'beat effect'. This I have far more sources for if you want.

[wilfulton]

I think we can agree for the most part that phase and pulse are more or less just technoblabbalations, but what about using both at the same time?

Phased pulse weaponry must be twice as good (the generators on Halo that give it an effective radius of 25,000 ly vs anything with sufficient biomass and cognitive capability to sustain the flood).


And phased plasma rifles in the 40 watt range (Terminator) are obviously more powerful than a rather feeble incandescent light bulb, so it must mean something, right? (despite the fact that plasma is inherently chaotic).

[Darth Wong]

Have you got a problem with math? The point remains: the power of two phase-coherent beams will not exceed their mathematical sum.

I think I'm doing a poor job of explaining. When a single laser beam hits a target, its energy will normally be entirely dispersed as heat into the target (ignoring albedo for a moment), because the excited electrons aren't going to go anywhere in particular.

Say though, you have two lasers and they are firing in 180 degree phase coherence. You then begin to cause a flux between the points of impact, and the energy that would normally evenly dissipate into the target at the target points instead creates a current between them.

Only insofar as it is converted to electrical current in the target material, which would depend on the nature of the target material. And I still see no reason to conclude that it would be especially powerful.

If you want to think of pure electricity, two wires, 180 degrees out of phase, crossing a light bulb will generate an alternating current twice as strong as a single wire going to ground.

Not if that single wire has twice the voltage. Obviously, opposing waveforms will produce a larger voltage differential, but it's silly to point out that they would produce more power than a single waveform of the same amplitude. Of course they would, but that doesn't mean anything because that's not what we're comparing it to.

No additional energy is being created, it's just being directed in a different manner than you are normally used to.

That better?

Yes, but then you are conceding the point; the combination would not be especially powerful; it would only produce unusual effects with the power it has.

[Eleas]

Do the adjectives "pulse" and "phased" weapons in sci-fi (as in lasers and particle beams) mean anything? Or are they usually just technobabble? What are the exceptions?

I always took "pulse phasers" to be a reference to the pact that they, I dunno, seem to fire discrete pulses of energy as opposed to the standard phaser beam. But I'm silly that way.

[Ariphaos]

Only insofar as it is converted to electrical current in the target material, which would depend on the nature of the target material. And I still see no reason to conclude that it would be especially powerful.

I would imagine that if a superconducting or near-superconducting material could be vulnerable to such an attack if it is unable to properly dissipate it.

Not if that single wire has twice the voltage. Obviously, opposing waveforms will produce a larger voltage differential, but it's silly to point out that they would produce more power than a single waveform of the same amplitude. Of course they would, but that doesn't mean anything because that's not what we're comparing it to.

Did I mention that it would actually generate additional power up there? I merely said it could be a powerful effect, and that they don't always work by straight addition if not 180 degrees out of phase.

If a material or composite requires an extremely tuned electrical field, then striking it in such a manner could have a potent effect.

Yes, but then you are conceding the point; the combination would not be especially powerful; it would only produce unusual effects with the power it has.

Fine. I was not referring to 'especially powerful' as in 'more power' but rather that the unusual effects could be potent (depending on target material).

[Braedley]

Only insofar as it is converted to electrical current in the target material, which would depend on the nature of the target material. And I still see no reason to conclude that it would be especially powerful.

I would imagine that if a superconducting or near-superconducting material could be vulnerable to such an attack if it is unable to properly dissipate it.

I'm just wondering how much physics you really know. If something is a perfect conductor (aka a superconductor) at the ambient temperature, then it also dissapates heat nearly perfectly at said temperature. Now granted, the object in question would still heat up a little, as the time constant k is determined by both the "hot" and "cold" objects associated with the governing differential equation, however, k is nearly 0 within the superconducting body itself, meaning it distributes heat almost instantaneously and uniformly.