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PEW-PEW !! USS Ponce deploys laser weapon in Gulf

sevenhelmet

Low calorie attack from the Heartland
pilot
As for anti-air, the atmosphere changes the higher you go so it's a lot more difficult to focus it in on the target (whereas at sea level it's constant and predictable).

That's a pretty bold statement...
 

sickboy

Well-Known Member
pilot
If you are a naval aviator, this thing should scare the shit out of you.


I got to be the target for one of the calibration runs a few month ago. It did, it didn't help that they wouldn't tell us the wavelengths so we went in hoping our LEPs would be enough. Luckily we can still see. That was six hours of "F&ck this noise"
 

Flash

SEVAL/ECMO
None
Super Moderator
Contributor
The radar range equation doesn't apply to lasers and the distances they can get out of this thing are phenomenal. Specifics I don't have, but from what we've covered it's got amazing potential. I know some lasers will actually use the atmosphere to help tune or focus the beam on the target. Atmospherics such as clouds and fog will affect it, however I see this being more as a small boat defense weapon (anyone notice where it was tested? hint, hint?). As for anti-air, the atmosphere changes the higher you go so it's a lot more difficult to focus it in on the target (whereas at sea level it's constant and predictable).

They still have to be aimed and even if they have potential they still have a very long way to go, there were a lot of good reasons the YAL-1 was cancelled.
 
According to some googling I did, the laser spread equation is: RT = 0.61 * D * L / RL

Where RT = beam radius at target (meters)
D = distance from laser emitter to target (meters)
L = wavelength to beam
RL = radius of laser lens or reflector

So with a wavelength of 1000 nm through a 2 meter telescope has a spot size of 12.2 cm at 100km. If the power output is 1 megawatt it could burn through about 1mm of graphite a second. It would burn through metal at a much higher rate.

Of course the published power of the laser on the Ponce is 30 kilowatts
 

nittany03

Recovering NFO. Herder of Programmers.
pilot
None
Super Moderator
Contributor
According to some googling I did, the laser spread equation is: RT = 0.61 * D * L / RL

Where RT = beam radius at target (meters)
D = distance from laser emitter to target (meters)
L = wavelength to beam
RL = radius of laser lens or reflector

So with a wavelength of 1000 nm through a 2 meter telescope has a spot size of 12.2 cm at 100km. If the power output is 1 megawatt it could burn through about 1mm of graphite a second. It would burn through metal at a much higher rate.

Of course the published power of the laser on the Ponce is 30 kilowatts
Hmm. Learning has occurred. So the range, if I'm doing my math right, is not linear with distance, but limited by the ratio of lens radius to wavelength. Still less than linear for a given power increase, depending on engineering constraints, but better than an inverse square law.
 

Beans

*1. Loins... GIRD
pilot
According to some googling I did, the laser spread equation is: RT = 0.61 * D * L / RL

Where RT = beam radius at target (meters)
D = distance from laser emitter to target (meters)
L = wavelength to beam
RL = radius of laser lens or reflector

So with a wavelength of 1000 nm through a 2 meter telescope has a spot size of 12.2 cm at 100km. If the power output is 1 megawatt it could burn through about 1mm of graphite a second. It would burn through metal at a much higher rate.

Of course the published power of the laser on the Ponce is 30 kilowatts
So it is an inverse square relationship... The power output of the beam is distributed in the spot. The spot is presumably a circle, with the area = <SEE ASTB STUDY SECTION>. So.... the intensity of that spot (like radar intensity) is its power/Area... and area goes like RT^2, and RT goes like distance, so intensity goes like 1/D^2.

The bonus here is that you have the 0.61 factor in there, and the L/RL can be used the same way you can focus a radar beam with a big reflector.

... ok someone post the nerds photo ...
 

sevenhelmet

Low calorie attack from the Heartland
pilot
What that equation apparently ignores is atmospheric absorption and scatter, although some nominal ballpark value could be rolled up somewhere in that 0.61 constant.
 

wlawr005

Well-Known Member
pilot
Contributor
My question is how they cool the thing. Pumping 50kw through a lense for any period of time is gonna heat the glass and distort the beam focus.

The NIF has finally gotten down to four hours between shots, however they're pumping 400 TW through their lasers.
 

Hotdogs

I don’t care if I hurt your feelings
pilot
Change lens like you change a barrel? or rotate it like most modern GAUs.
 
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