Re: [femm] Superconductor model

[Peter Schönhuber <Peter.Schoenhuber@xxxxxxxxxxxx>]

The equivalency of perfect conducting and superconducting material might be
a good starting point, although the physics behind is somewhat different
(look at the frequency behavior of both materials!).

Moreover, please keep in mind that identifying a material with a constant
permeability (whatever value) makes the assumption of homogeneity, linearity
and isotropy. Probably this is just a (very) rough approximation of a
real-world Type I - Superconductor. You won´t be able to model a Type II
Superconductor (high Tc stuff and all that) at all!

Best regards,

Peter Schönhuber


----- Original Message -----
From: "David Meeker" <dmeeker@xxxxxxxxxxxxxxxxx>
To: <femm@xxxxxxxxxxxxxxx>
Sent: Tuesday, May 08, 2001 11:37 PM
Subject: Re: [femm] Superconductor model




Vencislav wrote:

> Hello,
>
> this is my first question in this group:
>
> how do I make a model of superconductor in femm?
>
> I'm trying to see how will magnetic field behave
> when there is superconductor, since we know that
> superconductors do not let magnetic field lines
> go through it.
>

The easiest way to model a region filled with a perfect conductor is just to
assign it an extremely low permeability. You can't assign a region a
permeability that is exactly zero, because the problem would be too badly
conditioned to solve. But that's ok--assigning a relative permeability of
0.001 excludes flux nicely and generally solves ok.

Somebody even got a paper out of this technique once. If you are
interested,
you can check out:
A. Konrad and M. Graovac, "The finite element modeling of conductors and
floating potentials," IEEE Transactions on Magnetics, 32(5):4329-4311, Sept.
1996.

Dave Meeker




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