Solutions have been obtained for axially symmetric eddy‐current problems in two configurations of wide applicability. In both cases, the eddy currents are assumed to be produced by a circular coil of rectangular cross section, driven by a constant amplitude alternating current. One solution is for a coil above a semi‐infinite conducting slab with a plane surface, covered with a uniform layer of another conductor. This solution includes the special cases of a coil above a single infinite plane conductor or above a sheet of finite thickness, as well as the case of one metal clad on another. The other solution is for a coil surrounding an infinitely long circular conducting rod with a uniformly thick coating of another conductor. This includes the special cases of a coil around a conducting tube or rod, as well as one metal clad on a rod of another metal. The solutions are in the form of integrals of first‐order Bessel functions giving the vector potential, from which the other electromagnetic quantities of interest can be obtained. The coil impedance has been calculated for the case of a coil above a two‐conductor plane. The agreement between the calculated and experimental values is excellent.

1.
D. E.
Hughes
,
Phil. Mag.
8
,
50
(
1879
).
2.
Friedrich
Förster
,
Z. Metallk.
43
,
163
(
1952
).
3.
Friedrich
Förster
and
Kurt
Stambke
,
Z. Metallk.
45
,
166
(
1954
).
4.
Friedrich
Förster
,
Z. Metallk.
45
,
197
(
1954
).
5.
R. Hochschild, Progress in Nondestructive Testing (The Macmillan Company, New York, 1959), Vol. 1.
6.
D. L.
Waidelich
and
C. J.
Renken
,
Proc. Natl. Electron. Conf.
12
,
188
(
1956
).
7.
H. L. Libby, Broadband Electromagnetic Testing Methods, Hanford Atomic Products Operation, HW‐59614 (1959).
8.
K. W. Atwood and H. L. Libby, Diffusion of Eddy Currents, Hanford Atomic Products Operation, HW‐79844 (1963).
9.
T. J.
Russell
,
V. E.
Schuster
, and
D. L.
Waidelich
,
J. Electron. Control
13
,
232
(
1962
).
10.
P. R.
Vein
,
J. Electron. Control
13
,
471
(
1962
).
11.
David H. S. Cheng, Ph.D. dissertation (University of Missouri, 1964).
12.
Michael Leonard Burrows, A Theory of Eddy Current Flow Detection (University Microfilms, Inc., Ann Arbor, Michigan, 1964).
13.
C. V. Dodd and W. E. Deeds, in Proceedings of the Symposium on Physics and Nondestructive Testing (Southwest Research Institute, San Antonio, Texas, 1963).
14.
C. V. Dodd, A Solution to Electromagnetic Induction Problems, Oak Ridge National Laboratory, ORNL‐TM‐1185 (1965);
M.S. thesis, The University of Tennessee, 1965.
15.
C. V. Dodd, Solutions to Electromagnetic Induction Problems, Oak Ridge National Laboratory, ORNL‐TM‐1842 (1967);
Ph.D. dissertation, the University of Tennessee, 1967.
16.
C. V. Dodd and W. E. Deeds, Analytical Solutions to Eddy‐Current Probe Coil Problems, Oak Ridge National Laboratory, ORNL‐TM‐1987 (1967).
17.
Edward B.
Rosa
and
Frederick W.
Grover
,
Natl. Bur. Stds. (U.S.), Tech. News Bull.
8
,
1
(
1912
).
This content is only available via PDF.
You do not currently have access to this content.