Demagnetizing Factors of Rods and Tubes Computed from Analog Measurements

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Abstract
A method of computing demagnetizing factors using a resistance network analog or an electrolytic tank has been devised, and the demagnetizing factors for spheres, rods, disks, and tubes have been computed for the case μ = ∞. When the size of the model on the analog is appropriate, the value obtained for a sphere is within 1% of the theoretical value of ⅓. Although the demagnetizing factor is not a precise concept for rods, disks, or tubes, in which the induced magnetization is not uniform, this term is often used for convenience. In this paper, the ``ballistic demagnetizing factor'' (defined in terms of the mean magnetization over the median cross section of the object) is considered. The values obtained for rods and disks are compared with those found in the literature, principally with Bozorth and Chapin's compiled values. Typical results are 0.37 (0.47), 0.223 (0.27), 0.117 (0.14), and 0.052 (0.056) for (L/d) = ½, 1, 2, and 4, respectively, where (L/d) denotes the length‐to‐diameter ratio and the values in the brackets are the previously used values. The axial nonuniformity of the magnetization in rods and tubes is also measured and discussed.