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Magnet in a AC current solenoid

  1. Feb 10, 2012 #1
    when you place a magnet into a solenoid with a ac current it will get demagnetised. So does this mean that the magnetic field will go into the magnet in the opposite direction of the magnet's own magnetic field? and disalign it. meaning will the magnetic field enter the magnet as though it is like another piece of iron?

    thanks for the help!
  2. jcsd
  3. Mar 17, 2012 #2
    A rapidly alternating mag field will dis-arrage the mag-wessels. hence deenergising the same.
  4. Mar 17, 2012 #3
    Perhaps it's easier to consider the magnet as a large number of atoms. Since electron and protons have very small dimensions, most of the atom is empty space ( vacuum). So, the magnetic field "enters" the magnet. The filed there applies toque on electron magnetic dipoles.The torque doesn't simply rotate the dipole to get parallel with the field but it initially cause precession. the precession damps usually after a short time ( in order of nano-seconds) and the new alignment would be parallel with the applied field ( assumed strong enough to case the reversal)
  5. Mar 17, 2012 #4

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    This link,

    on page 27 & 28 (PDF pages 29 & 30) speaks to demagnetizing of transformer cores that have retained magnetism.

    They have a different shaped B-H curve than your permanent magnet but principle is same.

    If thet link doesn't work, search on : ittechinfoappguide.pdf

    and pick this one: www05.abb.com/global/scot/scot235.nsf/.../ittechinfoappguide.pdf
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