IEC 61000-2-9:2025

Overview

IEC 61000-2-9:2025 - Electromagnetic compatibility (EMC) - Part 2-9: Environment - Description of HEMP environment - Radiated disturbance - defines a standardized description of the high-altitude electromagnetic pulse (HEMP) radiated environment resulting from nuclear detonations. This edition (2025) replaces the 1996 version and provides updated information on spatial variation of the early-time HEMP, new material on late-time HEMP, and an informative Annex A that details waveform development and far-field considerations. The document is a basic EMC publication (IEC Guide 107) intended as a common reference for selecting realistic HEMP stresses for testing and protection design.

Key topics

• HEMP scenarios: differentiation of high-altitude vs. low-altitude nuclear bursts and emphasis on high-altitude effects relevant to civil systems (radiated disturbance only; no blast/thermal/ground shock at surface).
• Time-domain waveforms: standardized descriptions of early-time, intermediate-time and late-time HEMP components and the complete composite time waveform.
• Standard waveforms and analytic forms: development and comparison of waveform representations including double-exponential and alternate analytic forms (DEXP, QEXP) discussed in Annex A.
• Field components: characterization of both electric (E) and magnetic (H) field components, including spatial variation on the Earth’s surface and geomagnetic dip-angle dependence.
• Spectral/energy metrics: amplitude spectra and energy fluence distributions across frequency bands.
• Radiation interaction with environment: reflection, transmission and far-field region analysis for early-time HEMP at surface interfaces.
• Guidance for test stress selection: use as a reference to derive realistic radiated stresses for immunity testing and vulnerability assessment.

Applications

• Developing and validating EMC immunity tests and laboratory HEMP simulation waveforms.
• Designing hardening and protection measures for communications, electronic equipment, power systems and critical infrastructure.
• Performing risk and vulnerability assessments for utilities, transportation, telecommunications and emergency systems.
• Informing procurement, certification and regulatory requirements for equipment that must withstand HEMP radiated disturbances.

Who should use this standard

• EMC engineers and test laboratories
• Power system and utility planners
• Telecommunications and data-center designers
• Critical infrastructure protection specialists
• National regulators, defence and standards organizations
• Manufacturers of electronic and control systems

Related standards

• Other parts of the IEC 61000 series (Environment - Part 2; Limits - Part 3; Testing & measurement - Part 4; Installation & mitigation - Part 5)
• IEC Guide 107 (status as a basic EMC publication)

Keywords: IEC 61000-2-9:2025, HEMP, electromagnetic compatibility, radiated disturbance, high-altitude electromagnetic pulse, HEMP waveforms, EMC testing, critical infrastructure protection.