Magnet in a AC current solenoid

[sgstudent]

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!

 

[gosain_sanjay]

A rapidly alternating mag field will dis-arrage the mag-wessels. hence deenergising the same.

 

[Hassan2]

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)

 

[jim hardy]

This link,
http://www.google.com/url?sa=t&rct=...rey3Dw&usg=AFQjCNGKy8swuzdp-t8dpWyhgMX3vsrpTg

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

 

[sardar]

I can confirm that placing a magnet into a solenoid with an AC current will cause the magnet to become demagnetized. This is because the changing magnetic field produced by the AC current induces an opposing magnetic field within the magnet, causing its magnetic domains to become disordered and lose their alignment. This process is known as electromagnetic induction.

To answer your question, the magnetic field will not necessarily enter the magnet in the opposite direction of its own magnetic field. Instead, the magnetic field within the solenoid induces a magnetic field within the magnet that is opposite in direction, leading to the demagnetization. This is similar to how a transformer works, where the changing magnetic field in one coil induces a current in a nearby coil.

In terms of the magnetic field entering the magnet as though it is another piece of iron, it is not entirely accurate. The magnet itself already has its own magnetic field, and the induced field from the solenoid simply disrupts and weakens it. The magnet does not behave exactly like a piece of iron, as its magnetic properties are different due to the presence of its own magnetic field.

I hope this explanation helps clarify the phenomenon of demagnetization in a solenoid with an AC current.