[Not Soon(tm)] Space Beam Network

[raxo2222]

Question inspired by KSP Interstellar mod.

Lets say there is 2117 year.

We have colonies on Moon and Mars.

We already have established fusion powered beam network sending a lot of energy - most powerful generators creating around 100 - 1000 GW of energy.

What happens if such 100 GW beam misses target and lands on planet - lets say such spotsize is in between 100 - 10 000 meters.

Of course there would be difference between microwave beam sent from nearby station (low atmospheric absorption, but spreads out easily) and extreme UV one (almost 100% atmospheric absorption, but can travel far without spreading very much)

 

Can it cause forest fires/sunburns?

Can  few second exposure actually melt something?

 

Edited March 26, 2017 by raxo2222

[Shpaget]

100 GW shining on a circle with 10 km diameter delivers 1270 W per square metre. That is quite close to the radiation coming from the Sun (1370 W/m^2 in orbit, 1100 on the surface), so it would get quite hot - nice summer day hot, not counting the Sun. Combined with Sun, it could definitely start forest fires and cause sunburns - the Sun alone does that.

The same 100 GW beam shining on a 100 m radius is another story. Can you say death ray?

[Vanamonde]

What form does the beam take? Radio waves? Laser light? X-rays? 

[raxo2222]

1 hour ago, Shpaget said:

100 GW shining on a circle with 10 km diameter delivers 1270 W per square metre. That is quite close to the radiation coming from the Sun (1370 W/m^2 in orbit, 1100 on the surface), so it would get quite hot - nice summer day hot, not counting the Sun. Combined with Sun, it could definitely start forest fires and cause sunburns - the Sun alone does that.

The same 100 GW beam shining on a 100 m radius is another story. Can you say death ray?

That would be 10 000 times more flux - such beam could have such high intensity near source.

13 MW per square meter is a lot - that comparable with Sun's 63 MW / m^2 Temperature would be around 3900 K

(for emissivity of 1) meaning you can't stay too long under such beam.

Instant fires and stuff could actually melt and collapse when hit with it.

Black body would glow in orange light if stayed long enough in beam.

@FreeThinker can we model "Deadly Reentry" conditions, when our ship gets hit with powerful beam? Meaning it would heat up if we had for example had 2 receivers (beam would try to hit them), or if beam is too spread out.

1 hour ago, Vanamonde said:

What form does the beam take? Radio waves? Laser light? X-rays? 

Lets pick 3 wavelengths:

Microwaves, green light and extreme UV.

Thermodynamically there wouldn't be much difference - emissivity may wary for each wavelength, but stuff would melt/vaporise.

Wonder if ozone would give up if such powerful beam passed trough atmosphere.

And what we would see on moon/earth, while standing far enough to be safe and close enough to see its effects?

Edited March 26, 2017 by raxo2222