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Would space lightning last longer then earth lighting?

  1. Nov 21, 2011 #1
    I'm writing a paper on the possibility of harvesting space lighting, but the main question would be, does space lightning last longer then real lighting. My argument would be that air resistance cuases the channel which the current is traveling through to split. However in a vacuum, you would have a continous channel much like an electron gun in a CRT tube.
     
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  3. Nov 21, 2011 #2
    What do you think " space lightning" would be? And what would be it's cause? How would you measure its duration? (I don't know the answer to any of these questions.)

    Terrestrial lightning is based on leaders and ionized air....so most of "space" cannot conduct similar releases of energy. Although not completely understood, lightning has a number of unusual features such as:



    [Lots of good insights in this article.]


    http://en.wikipedia.org/wiki/Lightning




    Each of these requires a leader and I'd guess, but do not know, that this would be highly unlikely in a vacuum.

    However, there are huge clouds of rather free floating ionized gas in space and these can emit radiation of all sorts....some from gases being accelerated towards black holes. As for the most common clouds, such as near the centers of many galaxies, you'd have to decide if the concentration is sufficient to ionize very frequently.

    Also note in the Wikipedia article 'upper atmosphere lightning' and the SEE ALSO additional references at the bottom of the article.
     
  4. Nov 21, 2011 #3
    In my system, there would be a base on the moon and a satalite orbiting the van allen belts on earth. The satalite would stream electrons to the base and the base would stream protons to the satalite to create a channel. Lunar dust is known to be positively charged on the day side, and the van allen belts have a mixed charge. If the connection was formed, would it last longer than traditional lightning on earth?
     
  5. Nov 21, 2011 #4

    ZapperZ

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    No you don't.

    Look up "vacuum breakdown in RF cavities". The fact that you see "lightning" or "sparks" imply that there's a plasma that sets up, and thus, requires residual gasses. So by default, using the word "lightning" alone is sufficient to requires not a total, complete void of gas molecules.

    Zz.
     
  6. Nov 21, 2011 #5
    Would it be possible if you created some sort of plasma connection between the two charges. If so, could this be done using particle accelerators?
     
  7. Nov 21, 2011 #6

    davenn

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    nice idea, but pretty much impractical. For you to get the electrons to "stream" in any one direction they would have to be contained within a tube of some sort surrounded by a magnetic field to keep them on the "straight and narrow" else they would just fly off in any old direction.
    Over the 200,000++ km path you are looking at the positive charge on the moon would have to be astronomically huge even just to begin to attract the electrons.

    Think about what is happening in your old TV CRT tube, it if wasnt for the huge ~26,000 volts on the front part of the tube, the electrons would just shoot off at any angle.
    Thats 20kV thats needed only over ~ 1-2ft from the electron guns to the front of the tube.
    You are never going to generate the the huge voltages needed to attract electrons over several 100,000's of km

    Dave

    PS as far as I'm aware there is no such thing as space lightning, another bit of sci fi :)
     
  8. Nov 21, 2011 #7

    ZapperZ

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    What is "plasma connection between the two charges"?

    A plasma is highly unstable thing to play with. And now you want to add a particle accelerator? Do you know what is the typical wall-plug efficiency of a particle accelerator? I'd say that immediately, there goes your idea of generating power out of the window.

    Zz.
     
  9. Nov 21, 2011 #8
    I realize the idea is highly unlikely, and I am by no means in the interest to build such a device, but more on the side to make an interesting paper. That being said in response to davven. There should be on average a steady state magnetic field, such that there is a way to direct the protons and electrons. Once electrons have been been boiled off in an electron gun, they shouldn't experience much "friction" so it shouldn't matter the distance it travels. The hardest part would be to create a steady stream, and perhaps for this reason, the stream might only work for short distances.

    In response to zapperz. Most internet article describe ionized gas in space as a plasma. Hence when I refer to the electron and proton streams, they fall under the same category. And, like I said I know it would be very difficult to build such a connection between two streams, but if they did connect, would it have the same effect as lightning, such that a current would flow. I know that it wouldn't have the casdade effect, but I think it may be possible to extract energy from two charges in space.
     
  10. Nov 22, 2011 #9

    ZapperZ

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    And I think you haven't understood the phenomenon yet.

    A stream of electrons is not a lightning! A stream of electrons moving in vacuum does not emit light the way a lightning does! I work in a linear particle accelerator. Those bunches of electrons we shoot emit no lightning!

    But you are forgetting something here. Your whole premise is to tap a lightning in VACUUM with the presumption of taking advantage of the vacuum itself. I've just shown to you that a "lightning", by default, requires the presence of residual gasses! So this is no different than normal lightning that we see in the atmosphere, as far as this situation is concerned. This means that if you can't tap such a lighting under ordinary situation, what's the point in doing this in vacuum when the phenomenon is almost identical?

    Read "Vacuum Breakdown on Metal Surfaces" by Schwirzke (IEEE Transaction on Plasma Science, 1991) and learn a bit more on this phenomenon.

    Zz.
     
  11. Nov 22, 2011 #10
    The moon dust may be positively charged. But from this to a stream of protons it a very long way. How do you propose to use positively charged dust to create a stream of protons?
     
  12. Nov 22, 2011 #11
    I realize it wouldn't be lightning now, initally I thought it would be becuase I read this article.

    http://www.huffingtonpost.com/2011/...urrent-universe-space-lightning_n_882534.html

    I know a stream of electrons isn't lightning. What I was reffering to were leaders to connect the charges. This picture porbably describes it best.

    http://en.wikipedia.org/wiki/File:Leaderlightnig.gif

    Where the particle accelerators create leaders between the two charges.

    And finnaly, its just a thermodynamics paper. The reason I decided to write about space lightning was becuase I told my teacher I would write my paper about vacuum energy. My general understanding is that when you have an accelerating particle in space, it increases its energy through the unruh effect. Normal particle accelerators do this but they expend a lot of energy. The most practicle way to accelerate a body to remove energy is through a natural force. Lightning does this, but only lasts for a short time and is sporadic. My thought was that air resistence makes it harder to achieve a stable connection with the ground. This brought me to the conclusion that if you could connect two charged bodies in space, you would be accelerating charged particles between the two enough to say that the unruh effect is happening. My boldest statement would be to say that if you could replicate the same conditions on earth which cuase lightning, you would get the same thing in space. There are four things I could see happening; you would get some sort of glow (aurora) but not have a stable connection, you would get a stable connection but wouldnt create a flow, you would create a flow but it cuases an explosion, or you would create a steady flow which looks like some sort of plasma tube instead of lightning and your able to extract energy.

    @nasu- the base would have to have some sort of funnel so that the charge doesnt decide to hit anywhere else on the moon. The moons "leader" stream would use some sort of particle accelerator to start the connection. The same thing happens when you use a rocket to get artificial lightning, you create a path for it to flow through. My geuss is that more lunar dust will be "vacuumed" to the site through van der waals force. The funnel would focus the lunar dust.
     
  13. Nov 22, 2011 #12

    ZapperZ

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    And I would dispute that by what I have stated earlier, which I don't think you have understood. The "leader" ionizes the path of the surrounding gasses! There are no "surrounding gasses" in space/vacuum! This is the fatal flaw which you appear to not grasp.

    Think about it. If such a thing is THAT possible in vacuum, we would have see a gazillion of this in particle accelerators. After all, these moving charge particles are "leaders" in vacuum! By your faulty physics, there would have been this "lightning" following behind it, or caused by it!

    I will let you guess if such a thing is a common occurrence.

    Zz.
     
  14. Nov 22, 2011 #13
    My understanding was that you don't need gas to have a current. But the whole idea was based somewhat off cathode rays.

    "The gas ionization (or cold cathode) method of producing cathode rays used in Crookes tubes was unreliable, because it depended on the pressure of the residual air in the tube. Over time, the air was absorbed by the walls of the tube, and it stopped working.

    A more reliable and controllable method of producing cathode rays was investigated by Hittorf and Goldstein,[citation needed] and rediscovered by Thomas Edison in 1880. A cathode made of a wire filament heated red hot by a separate current passing through it would release electrons into the tube by a process called thermionic emission. The first true electronic vacuum tubes, invented around 1906, used this hot cathode technique, and they superseded Crookes tubes. These tubes didn't need gas in them to work, so they were evacuated to a lower pressure, around 10−9 atm (10−4 P). The ionization method of creating cathode rays used in Crookes tubes is today only used in a few specialized gas discharge tubes such as krytrons."
     
  15. Nov 22, 2011 #14

    ZapperZ

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    1. Are you trying to teach me about thermionic emission?

    2. When you "quote" something, you must cite the source.

    3. What does this have anything to do with what you are proposing? Thermionic emission has nothing to do with creating a spark or lightning.

    4. You are still missing the fact that electrons moving in vacuum creates no lightning or sparks.

    5. If all you care about is creating stream of electrons, I can show you easier ways of doing this. I do this for a living. However, this then has nothing to do with the topic of this thread that you created.

    Zz.
     
  16. Nov 22, 2011 #15
    1. Is it possible to connect two charges in space with a cathode ray.

    2. If it is possible, would the cathode ray provide a sufficient medium to transfer a current between the two charges.

    I think you understand where I'm coming from. I don't so much care about creating "lightning" but creating a current through space to connect two charges. In my paper, I propose that particles traveling through this current would accelerate and increase in energy due to the unruh effect. I realize a particle accelerator and electron gun combo might not be the best way to connect these charges. What do you propose would be the best way?


    link for above quote:
    http://en.wikipedia.org/wiki/Cathode_ray
     
  17. Nov 22, 2011 #16

    FlexGunship

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    What is this paper for? It just seems odd that there is so little to your idea other than a Srabble board's worth of sciencey words.

    What does the Unruh effect have to do with this? You're going to accelerate yourself quickly enough to see black body radiation from the stream of charged particles you're sending to earth? Given that an acceleration of 10,000,000,000,000,000,000,000 m/s2 corresponds to 1 Kelvin and the Earth's gravitational acceleration at the surface is a mere 10 m/s2 (rounded up, nonetheless) I don't think there is anything to this idea at all. I don't even know what this would gain you!

    From the start of this thread you have been in the weeds and poor ZapperZ has been trying sooooo hard to help you but you keep just missing what he's saying.

    What is your background with this topic?
     
  18. Nov 22, 2011 #17
    Its just a thermodynamics project where we look into possible future energy sources. The main goal is to make the paper interesting. I was trying to think outside the box since most people are going to write about fusion and renewable energy.

    The electrons initial acceleration when being fired from an electron gun is about 1E17 m/s^s.

    https://www.physicsforums.com/showthread.php?t=271682

    Still less then 1 Kelvin. My hypothesis is that if it is moving towards a positve charge it will accelerate slightly more. I get the effect would be negligible but its enough so that I could say it happens. If the system did work, most of the energy would be from the current between the two charges. Again, I wasn't going for practicality, just something interesting.
     
  19. Nov 22, 2011 #18

    FlexGunship

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    If you're firing it from an electron gun, then you've ALREADY imparted that energy into it. The only additional energy you'd be harnessing is from the gravitational potential from Earth which is negligible.

    If this is for a thermodynamics project, I think you should try for the highest grade possible which would mean thinking slightly more inside the box; you can still be creative. I'm sure that there's an incentive for you to use known thermodynamic principles in your paper... it isn't a creative writing class, after all.

    Why not explore the idea of solar collectors and targeted microwave transmission?
     
  20. Nov 22, 2011 #19

    Drakkith

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    If you already have positive charges, then simply providing a source of electrons would allow a generation of current. However I don't think the solar wind is full of just protons, but also electrons as well, so I don't think the idea would work. If you artificially generated the charges in a vacuum then you've expended energy already and at MOST you would only get back as much as you spent. In reality it would be even less due to losses.
     
  21. Nov 22, 2011 #20

    ZapperZ

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    You really should do your own calculation.

    Let's say you have a DC electron gun. You have an accelerating gradient of, say, 1 kV. Accelerate one electron, for simplicity sake. You have an electron with KE of 1 keV.

    1. Do you think you can convert 100% that energy to useable energy?

    2. Do you think that the electrical power you used to generate that 1 kV gradient, the energy you used to produce the electrons, etc. are LESS than the energy you will get from that electron that you accelerated? Remember what I asked you earlier about the wall-plug efficiency of a typical accelerator? This is where THAT comes in!

    If you submit this as your project, and I am your teacher, sure, I would say that you were "thinking outside the box", but you went for "style" but no substance. You failed to make consideration if you're using more energy than you generate!

    Zz.
     
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