How Do Bound Charges and Magnetization Affect Insulators?

[Niles]

Hi all.

I was thinking of something: Bound charges in an insulator arise because of the polarisation, so even though we have bound surface and volume charges, an insulator will still be electrically neutral.

I was trying to apply this line of though to a magnetized object. Here, the magnetization is due to bound surface- and volume currents. If the magnetization is 100% uniform, all the bound volume currents will cancel each other, and we will have a current around the edge of our object. If the magnetization is not uniform, we will have a bound volume current - in both cases, the net current is zero. And by net current I mean the current from bound volume and surface charges.

Am I corrent about this?

 

[Meir Achuz]

What do you mean by "net current"? If you mean \int{\bf j}d^{3}r,
that is zero in any static case. But there will be a non-vanishing bound solenoid-like current in a uniformly magnetized cylinder.

 

[Niles]

I mean net bound current - i.e. bound volume + surface charge