The pulse from an Intentional Electromagnetic Interference (IEMI) device can be far higher in magnitude and frequency than that of a nuclear EMP, though its effective range is far shorter, affecting only discrete “point” targets.
When manufactured as weapons, IEMI devices, also known as Radio Frequency (RF) weapons, can in some cases produce multiple, repeated pulses, and are typically quite mobile. A primary concern for such weapons (as for a Coordinated Physical Assault) is the potential for simultaneous strikes on multiple critical infrastructure nodes.
Since the assets most vulnerable are computers and electronics, this hazard has been characterized as a “dumb” cyber threat. IEMI weapons can damage or destroy microprocessors, corrupt or wipe out data on hard drives and could cause misoperation of relays and electrical arcing in high power system components such as transformers. Commercial and military versions of these systems are available or under development in a growing number of nations.
While utilities and government agencies have made progress in strengthening security against cyber threats, the destructiveness and sophistication of cyber weapons are growing. A successful, severe cyber-attack could cause serious damage to critical infrastructures, on national scales.