> Do you mean emergency thrust, takeoff thrust, or during cruise?
Doesn't matter, that's a percentage difference, and doesn't affect the orders of magnitude here.
> 1000 watts per square meter doesn't seem such a big deal.
Maybe you misread what I wrote, 1 kilowatt/m^2 is the power of direct sunlight. The power per square meter to power a jumbojet realistically needs to be 10s to 100s of times higher than that. And those are dangerous levels of power. For example, the risk of eye damage from reflections would be a significant concern, but realistically at those power levels you could risk melting plastics and so forth.
> Maybe you misread what I wrote, 1 kilowatt/m^2 is the power of direct sunlight. The power per square meter to power a jumbojet realistically needs to be 10s to 100s of times higher than that.
Indeed I did. However, I was primarily thinking about the waste heat, which would only be about 1 or two kilowatt/m^2.
> For example, the risk of eye damage from reflections would be a significant concern
I doubt this would be a concern for microwaves.
> but realistically at those power levels you could risk melting plastics and so forth.
That's only if all the power went towards melting those plastics. If the transmission and conversion is efficient enough, then this isn't necessarily the case. Also, just don't use plastics.
Shielding passengers inside a metal hull from 10 kilowatts/m^2 isn't that big a deal. Nor would dissipating 1.5 kilowatts/m^2 of waste heat.
10s of kilowatts, not 10 kilowatts. And that's for a huge, delta-shaped blended wing aircraft. If you take the takeoff power of a 777 and distribute it over the entire cross-sectional area of the plane you'll end up with several hundred kilowatts per square meter.
Even rounding down to 100 megawatts and then assuming a 70m x 60m triangle (2100 m^2) you end up with about 50 kilowatts per square meter. Now consider that the power gathering equipment not only needs to be extremely efficient (as even 95% efficiency would dump enough heat into the plane's structure to cause it to melt fairly quickly) but also needs to be built extremely carefully as any imperfection that resulted in a drop in efficiency for any small part of the plane would result in catastrophe.
And, of course, as mentioned there would be the problems of bleed-over and so forth. You want to be able to fly planes over populated areas, most likely.
The total power output of a 747 at takeoff is 90MW (90,000,000W), while cruising it is 45MW. (According to answers.com). A kilowatt is 1000W (you seem to have been mixing up megawatts and kilowatts).
Doesn't matter, that's a percentage difference, and doesn't affect the orders of magnitude here.
> 1000 watts per square meter doesn't seem such a big deal.
Maybe you misread what I wrote, 1 kilowatt/m^2 is the power of direct sunlight. The power per square meter to power a jumbojet realistically needs to be 10s to 100s of times higher than that. And those are dangerous levels of power. For example, the risk of eye damage from reflections would be a significant concern, but realistically at those power levels you could risk melting plastics and so forth.