MT 61000-2-9 - TC 77/SC 77C/MT 61000-2-9

IEC 61000-2-9: 2025 defines the high-altitude electromagnetic pulse (HEMP) environment that is one of the consequences of a high-altitude nuclear explosion. There are two cases of nuclear detonations:
- high-altitude nuclear explosions;
- low-altitude nuclear explosions.
For civil systems, the most important case is the high-altitude nuclear explosion. In this case, the other effects of the nuclear explosion such as blast, ground shock, thermal and nuclear ionizing radiation are not present at the ground level. However, the electromagnetic pulse associated with the explosion can cause disruption of, and damage to, communications, electronic systems, electric power systems and other portions of the commercial critical infrastructures, thereby upsetting the stability of modern society. The object of this document is to establish a common reference for the HEMP environment in order to select realistic stresses to apply to victim equipment for evaluating their performance and in order to develop protection methods to minimize the impacts of the HEMP. This second edition cancels and replaces the first edition published in 1996. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) updating the document to provide new information on the variation of the early-time HEMP on the earth's surface and to provide new information on the late-time HEMP;
b) adding a new informative Annex A which provides details concerning the development of the early- and late-time standard waveforms in the main body, an explanation of the advantages and disadvantages for the use of the double exponential waveform, and an explanation of the far field region for the early-time HEMP.
IEC 61000-2-9: 2025 has the status of a basic EMC publication in accordance with IEC Guide 107.