<br><font size=2 face="sans-serif">Thanks a lot Matt, Oliver, and Luigi
for the detailed (but important to me) answer.</font>
<br>
<br><font size=2 face="sans-serif">I get it now.</font>
<br>
<br><font size=2 face="sans-serif">Best Regards,</font>
<br>
<br><font size=2 face="sans-serif">Pei</font>
<br>
<br>
<br>
<br>
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<td width=40%><font size=1 face="sans-serif"><b>Matt Koch <mattkoch@scitex.us></b>
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<p><font size=1 face="sans-serif">03/16/2007 10:39 PM</font>
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<div align=center><font size=1 face="sans-serif">Please respond to<br>
mattkoch@scitex.us</font></div></table>
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<div align=right><font size=1 face="sans-serif">To</font></div>
<td><font size=1 face="sans-serif">Pei-Ying Hsieh <pei-ying.hsieh@siemens.com></font>
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<div align=right><font size=1 face="sans-serif">cc</font></div>
<td><font size=1 face="sans-serif">getdp@geuz.org</font>
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<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td><font size=1 face="sans-serif">Re: [Getdp] basic permant magnet question
- please help</font></table>
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<br><font size=2><tt><br>
Hello Pei-Ying,<br>
<br>
seems to me that for this equation to be true, the magnetic field in a
<br>
permanent magnet would have to be constant in space. Outside of the <br>
magnet it is H = nu*B and B = curl(A), so H = nu*curl(A), but inside the
<br>
magnet, it is H = Hc, i.e. the coercive field. There may be a <br>
simplifying assumption here, like assuming that the magnetic field <br>
inside a solenoid is constant in space.<br>
<br>
Regards,<br>
<br>
Matt Koch<br>
<br>
<br>
Pei-Ying Hsieh wrote:<br>
><br>
> Dear GetDP users:<br>
><br>
> I just started learning about magnetism. I have a couple of
basic <br>
> questions that I am not able to figure out. It will be appreciated
if <br>
> someone here can shed some light on this.<br>
><br>
> I have a permanent magnet - no electric current in the domain. I
<br>
> would like to calculate the magnetic flux density.<br>
><br>
> I have found a 3D code posted by Jasper in 2006. The questions
are:<br>
><br>
> 1. The governing equation for magnetostatics filed is:<br>
> Curl ( nu * Curl A) = J, where A is vector potential
and J is <br>
> electric current density.<br>
> Now, since there is no current, I will think that J
is zero.<br>
> 2. In the Formulation of getdp code (2D Magnetostatics example on
<br>
> getdp wiki),<br>
> it showed:<br>
> Equation {<br>
>
Galerkin { [nu[] * Dof{ Curl a}, {Curl a}]; In <br>
> Domain; Jacobian JVol; Integration I1; }<br>
>
Galerkin { [hc[], {Curl a}; In Domain_M; Jacobian <br>
> JVol; Integration I1;}<br>
> }<br>
><br>
> How does {hc[], {Curl a}} come into the equation? I believe that hc
is <br>
> Coercitivity of the magnet?<br>
><br>
> Thanks in advance for your reply!<br>
><br>
> Best Regards,<br>
><br>
> Pei<br>
> ------------------------------------------------------------------------<br>
><br>
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> getdp@geuz.org<br>
> http://www.geuz.org/mailman/listinfo/getdp<br>
> <br>
<br>
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