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Description of current density quantities welcome

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Hello fellow Comsol users,

let me ask you a short question: what is the relation of the quantities normJ and Jcoordinate (where coordinate is any space coordinate). In my study (2D axisymmetric) I modeled a single turn coil, driven by fixed current of 1A.

When integrating the current density quantities of the coil domain in postprocessing, I achieve confusing results: Jphi equals 1, Jr and Jz equal zero at all frequencies, as expected. But normJ equals 1 at 0Hz and >1 at frequencies >0Hz, e.g. normJ=1.36 @ 2kHz.

Afaik, a vector norm in 3D is defined as norm(v)=sqrt(v1^2+v2^2+v3^2), i.e. the square root of the sum of the norm of its components. In the above mentioned case, I would expect normJ to equal 1 at all frequencies. So obviously there is another definition of normJ in Comsol.

Unfortunately I cannot find any explanation of the relation of these current density quantities in the documentation set. If somebody could enlight my mind, this would be much appreciated.

Thanks in advance.
MV

0 Replies Last Post Oct 6, 2010, 4:13 a.m. EDT
COMSOL Moderator

Hello Marco Völker

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