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Replicate atmosphere of Earth, scaled down for experimenting

  1. Apr 1, 2013 #1
    I would like to analyse the effects of passing a laser/microwave through the Earth's atmosphere, in relation to space-based solar power.

    As I can't do my experiment on the real scale. I would like to know if it's possible to scale it down. I.e. replicating the relative amounts of gas at specific pressure levels in some container, to produce the diffraction effects that would occur from transmitting mw/laser from space to ground.

    Does Rayleigh-scattering come into play? Or just diffraction.

    Any ideas, how could I do it for my experiment?
     
  2. jcsd
  3. Apr 1, 2013 #2

    russ_watters

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    Can't you just use actual air?
     
  4. Apr 1, 2013 #3
    Nope.
     
  5. Apr 1, 2013 #4

    russ_watters

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    Ok.

    .......
     
  6. Apr 1, 2013 #5
    Obviously you can't just use air. There are much higher concentrations of some gases in the atmosphere. And gaseous attenuation, scattering and diffraction effects would occur on lasers/microwaves being transmitted through the atmosphere. So no, air just wouldn't do it.

    My idea is too concentrate the different atmospheric gases in a container and pass the wireless energy through, but I need some thought input into it, do I separate layers to replicate the different levels of atmosphere or does it not matter, or is it not possible to do.

    Again the goal is to replicate the scattering effect of the laser/wireless energy passing through the atmosphere, with a sensible scale.
     
  7. Apr 1, 2013 #6

    Bobbywhy

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    Astralfx, you are free to try experimentally measure the passage of laser and or microwave radiation through the Earth’s atmosphere but it will not be simple. On the other hand, the opacity/transitivity of our atmosphere across the entire electromagnetic spectrum has already been measured and documented.

    Accordingly, it may be more expedient for you to research these measurements to help to decide on passing which electromagnetic energy frequency through the atmosphere for your project.
    http://en.wikipedia.org/wiki/Absorption_(electromagnetic_radiation [Broken])

    and be sure to see this graph: http://en.wikipedia.org/wiki/File:Atmospheric_electromagnetic_opacity.svg

    Detailed studies of the effects of clouds, humidity, etc. have already been done as well.

    Bobbywhy
     
    Last edited by a moderator: May 6, 2017
  8. Apr 1, 2013 #7
    It will be difficult to mimic the "turbulence" in the atmosphere if you're trying to study spatial distributions. This has a big difference on light that passes through it from a source, take for example a large telescope. It's not just the presence of gas that causes distortion, but the motion caused by temperature gradient.
     
  9. Apr 2, 2013 #8
    Thanks, that will be very useful.

    My project is on space-based solar power. Generating solar energy via PV in a SPS, and powering a microwave transmitter or many smaller laser-based SPS. What I'm trying to think of is a practical project. I can do the theory easily, and analyse, modern costs, performance to an extent and other factors. But what I want is a practical project to go along with it, as I already have the idea of everything needed from space specific PV, microwave transmitter using vibrating crystals, recetennas for reciever, the only thing originally I didn't have was a small atmosphere. Any thoughts, on an experiment?
     
    Last edited by a moderator: May 6, 2017
  10. Apr 2, 2013 #9

    CWatters

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    Fly a transmitter on a balloon?
     
  11. Apr 2, 2013 #10

    sophiecentaur

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    I never can see the point of Solar harvesting up in space. We are not actually short of real estate on Earth and we can get 1kW for every msq on the actual surface. That is probably worth about a third or a quarter of what you could get from a msq up in orbit, allowing for day and night and atmospheric absorption. Making and launching a vehicle to carry the equipment and then converting, transmitting, gathering, receiving and converting, once again is going to account for a massive contribution to overall inefficiency. At best, any advantage must be only marginal. Where is the attraction in such projects?
     
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