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Beamed emission from pulsars

  1. May 8, 2012 #1

    RHK

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    Hello everybody.
    I am searching for an explanation about the beamed emission of pulsars, either in radio and in X-rays bands.
    I can not find a "standard" reason (with demonstration, eventually) for the beaming of this objects' radiation.
    Please, can you suggest to me something, or even a link or a pdf?

    Thanks in advance.
     
  2. jcsd
  3. May 8, 2012 #2

    Chronos

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    The intense magnetic field of a pulsar is the short answer.
     
  4. May 8, 2012 #3

    RHK

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    Too much short, perhaps :)
    Pulsars have a magnetosphere: why does the beaming occur only through the poles?
     
  5. May 8, 2012 #4

    Drakkith

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    Staff: Mentor

  6. May 8, 2012 #5

    RHK

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    I am sorry, I can not understand.
    From the link:
    "The beam originates from the rotational energy of the neutron star, which generates an electrical field from the movement of the very strong magnetic field, resulting in the acceleration of protons and electrons on the star surface and the creation of an electromagnetic beam emanating from the poles of the magnetic field."

    This does not explain the direction and the "tightness" of the beam.
    Can you be a little more clear for my understanding?
     
  7. May 8, 2012 #6

    Drakkith

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    I wish I could. I don't understand that well myself. Perhaps the magnetic field causes charges near the magnetic poles to gyrate around the field lines and produce the radiation, with the high density of field lines at the poles explaining the "tightness" of the beam. Just a guess though.
     
  8. May 30, 2012 #7

    RHK

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    Is there any other idea?
     
  9. May 30, 2012 #8

    Chronos

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    Other sources which may be helpful:
    http://burro.astr.cwru.edu/Academics/Astr221/LifeCycle/pulsars.html
    http://www.physics.usyd.edu.au/ugrad/hons/hons_courses/PA(05)20.pdf [Broken]
    Note as well that most pulsars are members of multiple star systems. This provides a source of material to 'feed' the beaming process. Not that this is absolutely essential to permit a pulsar to form, given their environment is typically 'polluted' to with remnant material from the parent star.
     
    Last edited by a moderator: May 6, 2017
  10. May 30, 2012 #9

    RHK

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    From the pdf document:
    "In polar cap models, the beaming is explained in terms of the relativistic beaming e ect for relativistic particles propagating along the magnetic eld lines, which implies that the radiation is con ned to a cone with half-angle 1/γ about the direction of the magnetic fi eld.
    This beaming is a feature of emission by relativistic particles and applies to all emission mechanisms that involve relativistic particles in one-dimensional motion along B."

    The question is: should I consider only the magnetic axis, and not the field lines direction?
     
  11. May 31, 2012 #10

    I checked into this myself. I concluded that 1) everyone agreed that the old theories were wrong. 2) Some said that it had been explained as an obscure consequence of general relativity 3) Others did not believe this.

    Everyone agreed that it was a difficult problem.
     
  12. Jun 1, 2012 #11
    There isn't one.

    There is very strong observational evidence that pulsars beam energy, however unlike the universe or particle physics, there is no "standard model" of pulsar beaming.

    Black holes and the entire universe are very simple. Anything with a magnetic field becomes complex to the point that we understand more about the big bang than we do about pulsar beaming.
     
  13. Jun 6, 2012 #12

    RHK

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    So, is there no model for the polar emission?
    I have found some (not well understood) explanations about the emission from the open field lines around the magnetic polar axis... is not this the "standard model"?
     
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