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Solar laser. Why not ?

  1. Jan 14, 2005 #1
    It is known that lasers are based on various media: on ruby crystals, on inert gases (Helium & Neon), on CO_2 etc. In Reagan's projects of Star Wars in the middle of 1980s the laser based on a nuclear explosion was discussed. Following this idea, one can expect to use the Sun as an active medium for a laser. Two satellites at diametrically opposite positions on a circular Solar orbit can carry two mirrors composing the laser.

    The sun can de understood as a completely ionized gas. Therefore orbital electronic transitions cannot be used for such a laser. However, there are quantum states of nuclei. Transitions between these quantum states possibly can produce a coherent radiation of the "gluon field". Why not ? This is the question for specialists. Let's discuss this project.

    Ruslan Sharipov, Ufa, Russia.
     
  2. jcsd
  3. Jan 15, 2005 #2
    That would sure shut Darth Vader up.
     
    Last edited by a moderator: Jan 15, 2005
  4. Jan 15, 2005 #3

    vanesch

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    Apart from the fact that you are a dangerous nutcase :surprised I don't think this can work. I HOPE that this cannot work, in fact! A "gluon" laser will have a few problems of confinement :biggrin: and of manufacture of the mirrors.
    But even a simplistic gamma laser (using nuclear transitions) will have a few difficulties. There will be a few technological difficulties in the manufacturing of gamma mirrors, but you will also have a more fundamental problem: the sun's matter being locally essentially in a thermal equilibrium, normally you don't get population inversion. So I don't see how you can get any laser action out of it.
     
  5. Jan 15, 2005 #4

    Nereid

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    Welcome to Physics Forums, Ruslan_Sharipov!

    In addition to the 'challenges' which vanesch identified, you would also have the problem of absorption; the baryons between the 'mirrors' will certainly have a non-zero cross section wrt whatever EM is passing through! Oh, and let's not overlook pair-production.

    What do y'all think, move this thread to TD?
     
  6. Jan 16, 2005 #5

    dextercioby

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    Let him have his second opinion...If it's as unrealistic as the first,then it should be moved.If my post turns out to be the last one in this thread,i don't see why...

    Daniel.

    PS.Never underestimate the power of imagination... :tongue2:
     
  7. Jan 16, 2005 #6

    vanesch

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    I would say that as long as the arguments use physics, it can be fun to think about it. If the aim is of course to promote gluon-vortex aether wave theory, it should go into TD :smile:

    cheers,
    Patrick.
     
  8. Jan 18, 2005 #7
    Nuclei before the decay and nucleai produced by fusion from smaller ones cannot be in thermal equilibrium with the surrounding matter.
     
  9. Jan 18, 2005 #8

    dextercioby

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    Then how would u explain the EQUILIBRIUM THERMAL RADIATION EMITTED BY THE SUN???????????????

    Or the light that we get is something else and we don't know... :wink:

    Please,don't keep it for yourself,share it with us...

    Daniel.
     
  10. Jan 19, 2005 #9

    vanesch

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    Ah, I think I see what you mean. You mean that hydrogen nucleae are in a higher energy state than the small nucleus in the ground state that will be the product of their fusion. This is correct, and if you take these degrees of liberty into account, you have indeed a population inversion (these degrees of liberty are indeed not in thermal equilibrium). But I fail to see how to exploit that "population inversion" in a laser activity. Nevertheless, you are right that the possibility exists. In fact, that possibility exists even in a bottle of hydrogen gas !
    I was more thinking about the nuclear levels for one given nucleus, in this case the levels of the smaller fused nucleae. THIS family of nucleae is not in a population inversion: there are many more in their ground state than in an excited state. So you cannot - in my opinion - make a laser based on that transition....
    Hmmmm...

    Except of course if there is a cascade ! Yes, you are right that in the first few steps of nuclear fusion, the system is NOT in thermal equilibrium: the energy of fusion is 14.1 MeV, and the sun's core isn't at 100 billion degrees.
    Nevertheless, if there is only one transition possible, there is no population inversion because there are many more in the ground state or the lower excited states. However, if, say, there is a level in the middle somewhere, and it is NOT the preferred down-cascade, then there might indeed be a possibility of population inversion. I don't know enough about the nuclear structure of the light nucleae to say something about it.
    What I can say, however, is that this is highly unlikely, because otherwise the sun would ALREADY work as a laser ! Not an oscillating one, because there's no cavity, but as a "one go" amplifier. Maybe it does, actually, but with such a low amplification factor (say, 1.1) that we don't realise it.... Mmmm, as I said, you ARE a dangerous nutcase :tongue:

    cheers,
    Patrick.
     
  11. Jan 19, 2005 #10

    vanesch

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    However, what kills the idea is of course the absorption of gamma radiation in the huge amount of matter it will have to cross. The gamma energy will be below 14MeV anyway, and that will be completely absorbed by the tens of thousands of kilometers of gas to be traversed... You will never have an overall factor larger than 1.

    cheers,
    Patrick.
     
  12. Jan 19, 2005 #11

    Nereid

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    Hmm, I have this vague recollection that someone else made a point similar to this, somewhere else .... but I just can't think who, or where
    :wink:

    Or is it a case of 'great minds think alike'? or perhaps 'fools never differ'?
     
  13. Jan 19, 2005 #12

    vanesch

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    Let's go for the first alternative :rofl:

    cheers,
    Patrick.
     
  14. Mar 5, 2005 #13

    gvk

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    Yes, it's right. The density of the sun's core is ~160 g/cm^3, and it's completely nontranslucent. The only way to consider any laser effect in man-made mirror cavity is to use the midea the corona of the sun. It is highly ionized hydrogen gas outside the chromosphere of the sun having the temperature of several millions K. It is equivalent to the electron energy ~10-13 eV. So, it is a good physical problem to consider a possibility of coherent X, ultraviolet, or visible emission.
    One mirror could be located on our Earth, other on satellite somewhere near Mercury :cool:.
     
    Last edited: Mar 5, 2005
  15. Dec 10, 2005 #14
    Two satellites orbiting the Sun.

    About one or two months ago on Russian TV I have heard a news that NASA has launched two satellites, as it was said, for making stereographic snapshots of the Sun. However, I couldn't find any information concerning this project on the NASA web site. Please, maybe someone has more info about this project or can give me the URL reference to its web site.
    Ruslan Sharipov,
    Ufa, Russia
     
  16. Dec 10, 2005 #15

    Astronuc

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    The nuclear pumped laser concept in Star Wars (SDI) was nevertheless chemical. X-ray lasers were considered, and these are constrained to the 0.1 MeV range.

    Diametrically opposed satellites around the sun will not pump the sun, not in the electron states and not in the nuclear states.

    As for the exciting states in the "gluon field", I would imagine that is quite impossible based upon the energy required in simple scattering experiments.

    The key here is analogous. Gluons have a short range influence. Even in fusion, the products will emit gamma rays, positrons and neutrinos, but the influence of the gluons is still within the nuclei or more accurate nucleons.

    Gamma rays are problematic. Gamma-rays with energy greater than 1.022 MeV generally produce electron-positron pairs, especially for high Z elements, and there is a competing Compton scattering effect.
     
  17. Dec 22, 2005 #16
    In atomic fission,a heavy nucleus splits into fragments and emits energy in different forms, for example photons. Do these photons have the same frequency, phase and direction? I don't know much about nuclear physics,could you please tell me?Thanks.
     
  18. Dec 22, 2005 #17

    ZapperZ

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    Think about it. How could they have the same phase when all of these do not occur coherently in the same time? And why would a particular direction in space be something special to the randomonly oriented nuclei that they will all emit radiation in that particular direction?

    Zz.
     
  19. Jun 9, 2007 #18
    To revitalize the discusion

    Now I would like to revitalize the discussion on the solar laser. I saw that making a nuclear laser is a very difficult problem. However, the Sun has an extremely hot atmosphere that stores a lot of energy. It is far from being in equilibrium, therefore, one can expect that in some places inside the solar atmosphere there are atoms or ions with inverse population of their energy levels. Such regions of solar atmosphere could be used in order to pump the energy directly from the Sun by means of a "Giant Optical Laser" or a "Giant Radio-Wave Laser".

    I know that NASA had launched the STEREO Mission.

    http://www.nasa.gov/mission_pages/stereo/main/index.html

    They spent a lot of money just for getting stereo images of the Sun. Placing their satellites on almost opposite positions on a circular orbit, they could shot a laser pulse or a radar pulse through the solar atmosphere and detect it on another satellite thus zonding the solar atmosphere for inverse population areas. My question is

    WHY THEY DID NOT DO IT ?

    Whom should I refer in order to suggest my idea for future missions planning? Please, help me to contact a person responsible for that in NASA.
     
  20. Jun 9, 2007 #19

    ZapperZ

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    This is a resurrection of a very old thread that should have gone to the now-defunct TD section in the first place. If you wish to continue with this (assuming you have SOME idea on how to make such radiation COHERENT in the first place), please do so in the IR forum.

    Zz.
     
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