# What does nonpermeable mean?

1. Nov 21, 2009

### Old Guy

1. The problem statement, all variables and given/known data

I'm reading Jackson Section 5.10, where he solves for a uniformly magnetized sphere "embedded in a nonpermeable medium." I'm not looking for an example, but to understand what it means. It can't mean there is no B or H field external to the sphere; in fact, Jackson has a figure showing field lines. Does it perhaps mean that there is no source of B or H external to the sphere? But if that's the case, wouldn't the exterior region be free space which has a permeability?

2. Relevant equations

3. The attempt at a solution

2. Nov 21, 2009

### gabbagabbahey

The definition of magnetically non-permeable is that the material has the same magnetic permeability of free space $\mu=\mu_0$, and hence will have zero magnetization.

3. Nov 21, 2009

### Old Guy

Thanks, I can accept that. Just seems like an odd choice of words (or maybe my many years working with fluid flow in porous media . . .)