Magnetic Enrgy (B^2/2u or H^2/8pi)

[asheg]

Hi,

I have a problem that in some references the magnetic energy is B^2/(2 mu) and in some references it is H^2/8pi. is it a matter of units and if it's so what is the name of these unit system (i.e. MKS). How I can convert them.

 

[dextercioby]

First of all B and H are not the same thing. Next comes the problem with units. Please, read here http://en.wikipedia.org/wiki/Magnetic_field

 

[asheg]

First of all B and H are not the same thing. Next comes the problem with units. Please, read here http://en.wikipedia.org/wiki/Magnetic_field

Thank you for your reply,
But it doesn't answer my question perfectly. I know the difference between H and B. I want to know why in a system we have (Energy = mu H^2/2) and in other (Energy = H^2/8 pi)

 

[dextercioby]

The $\pi$ part comes from the CGS system with nonrationalized units, more on which you can read also on wiki: http://en.wikipedia.org/wiki/Gaussian_units

 

[asheg]

Thank you, It answers my question perfectly this time