Schmucker-Weidelt Lecture Notes, Aarhus, 1975 - MTNet

The field within the conducting sphere, r - < a, is derived from - P
as described in Sec. 7.3. Observing that the radial component of
rot rot - P reduces by the use of spherical harmonics to
the field components of the spherical harmonic of degree n and
order m are:
and
The impedance of the field at spherical sur'aces, expressed in
terms of c:, is then as in the case of plane donductors given by
For the field outside of the conducting sphere, r - > a, the solution
of the radial function is (in quasi-stationary approximation)
Hence, the surface value of the charlac-terisll-ic scale length for
r = a is found to be
The ratio of internal. -to external. parts of the magnetj.~ surfacc
fleld is by definition