# Coaxial coils in dielectric material

1. May 29, 2012

### orcaja

Hi everyone

I have a problem to solve, I already simulated it with FEMM, but I wonder if it is possible to find an analytical solution.

Let's say that there's a small coil (100 turns) around a pipe (2in diameter), the pipe is filled with air.
This pipe is located inside a bigger pipe (8in diameter), which also has a coil similar to the first one (100 turns), the two coils are aligned (coaxial). Outside of this pipe there is air.

The space between the two coils is filled with two layers of different diamagnetic materials.

The outside coil is excited with an ac signal, (let's say 1Vpp, 100kHz).
Neglecting the effect of the pipes, (i.e. just taking into account the effect of the diamagnetic materials, and the air) How can I calculate the induced voltage in the inside coil?

I'm really a beginner, but willing to try everything, right now I'm having a look at the book
classical electrodynamics by David Jackson, but I still don't have an idea how to solve it.