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Magnetic field question

  1. Feb 4, 2010 #1
    So I have had a question running through my head for a while now.

    Can a magnetic field be projected???

    I guess that is very general so to elaborate what I am asking is that could you make a device that can cause an item outside of itself to have a magnetic field? Also is there any way to induce a magnetic field in a non conductive material?
  2. jcsd
  3. Feb 4, 2010 #2


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    Conductivity is not the same as magnetization. The ability to induce secondary magnetic fields in an object is called magnetization. A classical explanation of this phenomenon is that microscopic current loops are aligned with the applied magnetic field. The macroscopic result of all these aligned current loops is a macroscopic effective current loop that creates its own magnetic field. In a ferromagnetic material, the alignment of these loops, or domains, can be retained after the applied magnetic field is gone. So you can create a permenant or at least temporary magnet by applying a strong magnetic field to a suitable material. Indeed, this is how many permanent magnets are created, in addition to other steps like heating to a high temperature.

    So I do not quite understand what you are asking. In my mind, the fact that we can place a magnet on a table, a piece of pig iron off to the side and magnetize the iron seems to satisfy your question.
  4. Feb 5, 2010 #3
    The big magnet used for the 184" cyclotron at UC Berkeley (Lawrence Radiation Lab) had a stray magnetic field up to 60 Gauss that extended ~50 feet out from the magnet. The magnet pole tip diameter was about 184", and the gap was big enough to crawl in to. The field in the center was about 2.4 Tesla, and the iron saturated at about 1.6 Tesla, so the rest of the field was essentially like a big Helmholz coil.
    http://imglib.lbl.gov/ImgLib/COLLECTIONS/BERKELEY-LAB/images/96803598.lowres.jpeg [Broken]
    Bob S
    Last edited by a moderator: May 4, 2017
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