Lasers in atmosphere

[Carlobrand]

I want to make sure I understand this right. My knowledge of physics is about the level of interested amateur, so...

Half-Value Layer - X-rays | nuclear-power.com

The half-value layer expresses the thickness of absorbing material needed to reduce the incident radiation intensity by a factor of two. Half-Value Layer - X-rays

www.nuclear-power.com

Half value layer for a 100 keV x-ray beam in air is 35 meters. Near as I can tell, ship lasers at TL13+ are x-ray lasers. So, you're landed, you pump 250 MWs into a laser to deal with an approaching APC. Half the energy gets dumped into the air over a 35 meter distance? We just dumped 125 megajoules into a line 35 meters long? That's, what, equivalent to 60 pounds of TNT? Did I do that wrong?

 

[Spinward Flow]

Near as I can tell, ship lasers at TL13+ are x-ray lasers.

Correct.

Half the energy gets dumped into the air over a 35 meter distance?

Not exactly.
According to the table at the bottom of the page:

Absorber	100 keV	200 keV	500 keV
Air	3555 cm	4359 cm	6189 cm

For our purposes, 1EP = 250MW ... not 250kW.
250MW = 6.241388888888887E+21 eV ... or 6.241388888888887E+18 keV ...

In other words, a 250MW pulse laser is 12,482,777,777,777,777x more powerful than the 500 keV example given for reference on that page.
That's almost 12.5 quadrillion times more powerful.

I'm thinking that might change the half-value layer of "air" by ... a little bit ...
Your mileage may vary, of course.

 

[kilemall]

Fusion changes everything.