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B The Sun's magnetic field

  1. Aug 28, 2018 #1
    https://phys.org/news/2018-08-image-sun-magnetic-field.html#jCp

    These fields are generated by the solar wind?
    By the sun spinning does it generate another mag field?

    Is this a good example of how hot objects loose their coherent magnetic field by misaligned temperature generated ad hoc domains making the overall magnetic field incoherent? Once the heat breaches the shell of the object the solar wind starts flowing and it disrupts the overall magnetic field. Earths core is hot and spins but the earth still has a coherent magnetic field is this because the heat hasn't penetrated the crust?
     
  2. jcsd
  3. Aug 28, 2018 #2

    Drakkith

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    I don't believe so. I believe they are formed from currents of charged particles inside the Sun.

    Not really. The Sun isn't composed of small magnetic domains like a magnetic metal is. If you cooled the Sun down its magnetic field would probably not get stronger.

    This doesn't look correct to me. The entire surface of the Sun (the photosphere) is thousands of degrees in temperature and heat is constantly leaving in the form of electromagnetic radiation. There are no spots where the heat doesn't 'leak' out.

    The Earth's magnetic field is generated from a dynamo effect, not because of the Earth's surface is insulating against heat loss. Besides, the Earth's crust still radiates energy from every location, just like the Sun does, so the heat has indeed 'penetrated' the crust. Most of the radiation is in the infrared region of the spectrum, versus the Sun's spectrum where most of the radiation is in the visible and near-IR parts of the spectrum.
     
  4. Aug 28, 2018 #3

    davenn

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    OK lets get the image in here so it is easy for all to see
    Note, despite the Aug 2018 date of the article .... modelling the magnetic fields like this has been done for quite some years

    imagesunsmag.jpg



    Agreed

    The source of the solar wind originates in the solar corona, well above the photosphere ( the visible surface ) of the sun.
    The corona is substantially hotter than the photosphere at more than 1 million K compared to ~ 5700 K for the photosphere.



    The sun does have an overall magnetic field ( not sure that solar rotation causes it tho?)
    The magnetic fields you see in the above image are localised ones related directly to active regions.
    These active regions are where the Suns magnetic field penetrates the photosphere and produces sunspots ....

    Sunspots-24a151h.jpg


    Now referring back to the first image, you will note something that stands out ...... areas of intense magnetic fields, the bright active
    regions and areas of almost no magnetic field activity as in the upper left of the sun. These dark areas of no magnetic fields are called
    coronal holes and show areas where the magnetic field lines are not connected as they are over those bright active regions.
    Coronal holes are areas where the magnetic field streams out into space and with them high speed streams of solar wind ( much
    higher than the average solar wind speed)
    The avg speed is around 300 km/s and from coronal holes speeds often reach 800 to 1000 km / s
    and occasionally up to ~ 1200-1400 km / s.


    This is a bad assumption. Heat from the interior of the Earth DOES penetrate the crust .... have you
    heard of volcanoes ??



    Dave
     
  5. Aug 30, 2018 #4
    I was looking at the multiple domains on the image.
    I was thinking the overall field would be more aligned with less disrupting ad hoc magnetic fields.
    Does electromagnetic radiation generate a magnetic field when moving?
    I know the magnetic field is not generated because the earth is insulating the heat, got more to do with the earth and core spinning? I'll check out the dynamo effect. I was thinking the insulation was not allowing the heat to influence the earths magnetic field and therefore making it more coherent.
    If I go to space away from the earth and all the other objects of influence and take out my compass will the needle point to the suns north pole?
     
  6. Aug 30, 2018 #5

    Drakkith

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    Not in the way that you're thinking. Electromagnetic radiation is a wave in the electromagnetic field, so one component of it is a changing magnetic field. But this doesn't set up a large magnetic field like moving charges do.

    Heat doesn't affect a magnetic field directly. Instead it affects the magnetic domains (in a magnetic solid like iron). An external magnetic field passing through a material at 2,000 degrees would remain unaffected.

    It will point along the local magnetic field lines, which would be the Sun's. This might point towards the Sun's north pole (which is a south magnetic pole, just like the Earth's north pole) but it may also point up and out of the plane of the solar system depending on where you are and the exact details of the magnetic field. Note that the Earth's magnetic field lines run roughly parallel to the surface when you're near to Earth, which is the reason we can use a compass to help us find direction. The needle doesn't actually point towards the north pole, it points along the magnetic field line. It's just that we're restricted to moving along the surface of the Earth, and moving in the direction of the compass needle moves us along the field lines towards the pole. However, if you're far from Earth and no longer restricted to moving on its surface, a compass becomes mostly useless as a navigation device.
     
  7. Sep 3, 2018 #6
    If the sun and earths moving EM aren't generating their overall magnetic fields and earths magnetic field can also be generated without solar wind leaving the earth to carry it, what's carrying earths magnetic field? Not all magnetic fields require a moving charge to physically generate the field at that location in the field?

    Can you think of the earths magnetic field as a electric field with moving charges constantly alternating between the north and south poles in the field and the moving charges physically generate the magnetic field?
     
  8. Sep 3, 2018 #7

    Drakkith

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    I'm sorry I don't know what this is supposed to mean. EM is short for electromagnetic, but something that's a term that describes something, such as a field or a wave. It's not something in and of itself.

    Nothing. An EM field requires nothing to 'carry' it.

    Nope. And the way you've worded it makes it sound like a charge is required everywhere in a field in order to generate it. But that can't be correct, because there are often empty spaces between particles but the field is not zero between them.

    No, as the alternating charges would generate electromagnetic waves instead of a magnetic field.
     
  9. Sep 3, 2018 #8
    Sorry, EM = EM radiation
     
  10. Sep 13, 2018 #9
    If moving charged particles of the solar wind generate a magnetic field, what do the moving charges spinning with the sun generate?
    Something needs to move the needle on the compass, a charge flowing between the poles would have the right moving directional momentum to physically move the magnetic needle to point north when the moving charges interact with the magnetic compass needles poles?
    Dark Energy?
    https://www.express.co.uk/news/worl...latest-Mount-Kilauea-magnetic-field-compasses
     
  11. Sep 13, 2018 #10

    Drakkith

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    No, not at all. This doesn't even make any sense. You've simply strung together a series of science words without understanding anything about them. Instead, I recommend starting with more fundamental concepts before moving on. Otherwise you just skip over all of the basic concepts that you'll actually need to understand the more advanced concepts. As an example, if you remove the idea of a 'field' that serves as the medium for a force, you now have to replace that idea with something else that also works just as well. But we can already explain electromagnetism to an incredible degree of accuracy using the concept of a field. So accurately that we can't actually detect any difference between our experiments and our predictions.

    Please don't make random guesses. It doesn't facilitate a useful and productive discussion. Remember that PF exists to teach science as it is currently understood and practiced by the mainstream scientific community. Throwing out random ideas before having a firm grasp on how mainstream science currently understands them does not meet our mission statement. I don't say this to be rude, only to help guide you towards actually learning real science, not the watered down stuff you find in 99.9% of youtube videos and popular science books.
     
  12. Sep 14, 2018 #11
    To move something you need to transfer acceleration to that thing in the direction of motion?
    Is there dark energy in "empty space" between objects in space where the field is not zero in mainstream science?
     
  13. Sep 14, 2018 #12

    Drakkith

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    No. Acceleration is not something that can be transferred. Acceleration is the change in an objects velocity over time and occurs as the result of an applied net force on the object.

    Dark energy, as it is currently understood by mainstream cosmology, has absolutely nothing to do with this and discussing it without dedicating an entire thread to it would not be very productive. I say that because your question cannot be answered with a simple yes or no, as dark energy is not understood well enough to give concrete answers. However we understand it well enough to know that it does not have anything to do with the topic of this thread.

    If you want to find out more about dark energy I suggest making a new thread in the cosmology forum asking for information and references. However, be aware that understanding dark energy at even a beginner level requires at least a basic understanding of many different advanced concepts, so don't expect to be able to spend a handful of minutes reading a couple of posts and come away with an understanding of dark energy.
     
  14. Sep 15, 2018 at 3:25 AM #13
    A applied net force doesn't transfer acceleration to a object when moving it. wow...
     
  15. Sep 15, 2018 at 4:32 AM #14
    A applied net force doesn't transfer a change in an objects velocity over time when moving it. wow...
     
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