Update of IEC 61000-2-9: Description of the HEMP Radiated Environment

Edition 1 of IEC 61000-2-9 was developed in the early 1990s and published in 1996; it provided information on the early-time (E1), intermediate-time (E2) and the late-time (E3) HEMP radiated environments, including worst-case waveforms for each time period to be used for coupling to commercial systems and equipment. This approach was similar to that used for military systems at the time, as the location of a high-altitude burst is unknown and is only under the control of the attacker. Military systems during the Cold War considered that there would be many high altitude bursts during a nuclear attack, and therefore it was likely that all important military systems would be exposed to the maximum HEMP fields. Given that all commercial systems may not need to consider the worst-case threats due to the fewer high altitude bursts and the possibility of recovery over time, it was decided that the new edition of IEC 61000-2-9 should contain more information concerning the variability of the HEMP waveforms. This was done in particular for the E1 and E3 HEMP waveforms.