In this paper, linear lightning diffusion into a Faraday cage is studied. The high-altitude Electromagnetic Pulse (HEMP) and nearby lightning are used as examples for a uniform field drive and the direct-strike lightning adjacent to the enclosure is used as a worst-case configuration of a line source excitation. The time-derivative of the magnetic field (HDOT) inside the enclosure for a uniform field drive with a decaying exponential waveform is analyzed and numerically determined. The physically relevant time-derivative of the magnetic field and voltage characterizations of an optimum coupling loop inside the enclosure for a decaying exponential waveform in a worst-case line source coupling configuration are numerically determined. First, the impulse and the unit step response peaks are shown to bound the decaying exponential peaks. Next, a simple fit function for a decaying exponential peak HDOT or a voltage bound for a single-turn loop inside the Faraday cage is constructed from peak responses of the unit step and impulse limiting cases. Excitations used are from (1) a uniform field drive of HEMP or nearby lightning and (2) a line source of direct-strike lightning. Comparisons of HDOT and voltage bounds of the fit function and actual numerical evaluations are given in Table 3.
Kenneth Chien-Ying Chen,
Yau Tang Lin,
Larry Kevin Warne,
Kimball O. Merewether,
"Linear Diffusion into
a Faraday Cage," Progress In Electromagnetics Research M,
Vol. 23, 299-311, 2012. doi:10.2528/PIERM12010410
1. Lee, K. S. H. (ed.), EMP Interaction: Principle, Techniques, and Reference Data, 559-573, Revised Printing, Hemisphere Publishing Corporation and Taylor & Francis, 1986 and 1995..
2. Warne, L. K., W. A. Johnson, and K. C. Chen, "Maximum interior voltage and magnetic field penetration through a linear conducting layer," Journal of Electromagnetic Waves and Applications, Vol. 9, No. 4, 569-598, 1995.
3. Chen, K. C., Y. T. Lin, L. K.Warne, and K. O. Merewether, "Linear diffusion into a Faraday cage,", Sandia National Laboratories, Albuquerque, NM, SAND2011-8012, November 2011.