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ArcticMyst Security by Avery

the numbers: laser weaponry

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Jan 28, 2015
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Alright, enthusiasts.
i am going to do some of the math in what it would take to make a viable laser rifle.
2014.11.24.NewsletterScreen2-1080.jpg

So, i'm going to define some arbitrary numbers here, that we will use to math our way through.
1)the lethal dose of laser is enough energy to vaporize 10 mols of water (about 200 grams)
2)the absorbance of the target is .3 (70% of the energy is not absorbed)
3)laser effeciency is about 25%
4)we want to have to shoot the enemy for more than 1/4 of a second.

Alright, first off. We look to mine out more constants.
i) according to wikipedia the energy of vaporization of water at body tempreture is 43500 Joules per mol (43.5 KJ/mol)
Actually, i think that's the only constant that we need.

calculations
so, you want to vaporize 10 mols of water in .25 seconds?
10 mols of water is 435KJ of energy that we hope to get in .25 on the clock, eh?
that's about 1.740 Mega watts.
that's a class V laser putting out 1,740,000 watts of photon energy.
that's if you're bare nekkid, and you just take in the energy.
according to above, we are only absorbing 30% of the energy at best.
this bumps us up to 5.8Mw. (That's a capital M for MEGA).
at 25% effeciency that bumps us to 23.2MW of power dissipation
at 3.7 volts that's 6270 Amperes.
if you're looking to do that, aside from the diode, it's possible. Just hook up 41 car batteries in parallel
And the diode may be possible, too. livermore is creating a supposed 1Pw laser (1,000,000,000,000,000 watts). If the laser could fire for a quarter of a second, it would be enough to kill 4,347,000 humans in one go.
Go figure.
 





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So we're just waiting for 41 car batteries to be reduced to something more portable. ;)

Imagine the size of the heatsink!
 

Teej

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41 car batteries....how many 18650's is that? I might have that many....

:D

On the other hand...if laser rifles, etc, became common, just as we use Kevlar, etc, for bullets, we'd use reflective armor for lasers, etc.

Also, what wavelength are the calculations for?
 
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A bank of ultra capacitors could be wired together and charged to provide a single pulse. What size wire do you need for 6270 Amps? LOL!

Alan
 
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41 car batteries....how many 18650's is that? I might have that many....

:D

On the other hand...if laser rifles, etc, became common, just as we use Kevlar, etc, for bullets, we'd use reflective armor for lasers, etc.

Also, what wavelength are the calculations for?

2944 of those suckers
my calculations use absorbance, not wavelength
 
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Teej

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2944 of those suckers
my calculations use absorbance, not wavelength

Not even a half Tesla pack...so your Tesla could power it with room to spare.

:D



Wouldn't the surface being lased be a factor in how much energy was absorbed vs reflected?
 
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A bank of ultra capacitors could be wired together and charged to provide a single pulse. What size wire do you need for 6270 Amps? LOL!

And speaking of pulses, much higher peak power could be achieved with pulsing, requiring less average power and possibly requiring far less time to do damage. A quarter second is actually rather a long time to train on a single location on a moving target.
 
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Less amps, more volts.

fewer amps ;)

it's possible. Just hook up 41 car batteries in parallel

And what is that number based on?

livermore is creating a supposed 1Pw laser (1,000,000,000,000,000 watts). If the laser could fire for a quarter of a second

It couldn't. The only way you get powers that high is to drop the pulse duration into the femtosecond range. Average power is not impressive at all.

23.2MW of power dissipation
at 3.7 volts that's 6270 Amperes.

You missed three zeroes there. :undecided:
 
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fewer amps ;)



And what is that number based on?



It couldn't. The only way you get powers that high is to drop the pulse duration into the femtosecond range. Average power is not impressive at all.



You missed three zeroes there. :undecided:

A) 13v car battery running oaon 40 amperes.
and It appeares i missed many zeroes
 
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Whoa wasn't expecting to see a Dust514 pic on here but I have that game on my PS3

Also Dust514 lasers are yellow not blue but whatever
 
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