The EMP Threat: The State of Preparedness against the Threat of an Electromagnetic Pulse (EMP) Event

Key Findings from the EMP Commission Report of 2008

The Commission to Assess the threat to the United States from Electromagnetic Pulse, on which I served as principal staff, made a compelling case for protecting critical infrastructure against the nuclear electromagnetic pulse (EMP) and geomagnetic disturbances (GMD) caused by severe solar storms. Their 2008 Critical Infrastructure Report explains EMP effects, consequences, and protection means for critical infrastructure sectors. EMP and GMD are particularly challenging in that they interfere with electrical power and electronic data, control, transmission, and communication systems organic to nearly all critical infrastructures. The affected geography may be continental in scale. EMP and GMD events thus represent a class of high-consequence disasters that is unique in its coverage, ubiquity, and simultaneous system debilitation. Such disasters deserve particular attention with regard to preparedness and recovery since assistance from nonaffected regions of the nation could be scarce or nonexistent. The major point I want to make to Congress is that such disasters are preventable. We have the engineering knowhow and tools to protect ourselves. What is lacking is resolve.

Brief Tutorial on EMP and GMD Phenomenology

A brief tutorial on EMP and GMD phenomenology will be helpful to the discussion. The nuclear electromagnetic pulse (EMP) results from a nuclear burst high above the jet stream. A similar effect can occur naturally when an intense wave of charged particles from the sun perturbs the earth’s magnetic field, causing a solar storm GMD. In the case of high altitude nuclear bursts, two main EMP types come into play that I will refer to as the “fast pulse” and the “slow pulse.” The fast pulse EMP field, also referred to as E1, is created by gamma ray interaction with stratospheric air molecules. It peaks at tens of kilovolts per meter in a few nanoseconds, and lasts for a few hundred nanoseconds. The broad-band frequency content of E1 (0-1000 megahertz) enables it to couple to electrical and electronic systems in general, regardless of the length of their penetrating cables and antenna lines. Induced currents range into the 1,000s of amperes. Exposed systems may be upset or permanently damaged. 

The “slow pulse” EMP, also referred to as E3, is caused by the distortion of the earth’s magnetic field lines due to the expanding nuclear fireball and rising of heated and ionized layers of the ionosphere. The change of the magnetic field at the earth’s surface induces currents of hundreds to thousands of amperes in long conducting lines (with lengths of a few kilometers or greater) that damage components of the electric power grid itself as well as powered systems. Long-line communication systems are also affected, including copper as well as fiber-optic lines with repeaters. Transoceanic cables are a prime example of the latter.

Solar storm GMD effects are the result of large excursions in the flux levels of charged particles from the Sun and their interactions with the Earth’s magnetic field. The electrojets from these storms, depending on their orientation, generate overvoltages in long-line systems over large regions of the earth’s surface affecting electric power and communication transmission networks in a similar fashion to EMP/E3. Note that protecting long-line systems against EMP (E1 and E3) also affords protection against GMD effects. The converse is not true. Protecting electric transmission systems against solar storm GMD/E3 does protect against EMP/E3 –but defending against the fast pulse EMP/E1requires different equipment. 

Long-line connected equipment is especially vulnerable to EMP and GMD

Similar to protecting critical infrastructure against any hazard, it will be important to develop risk-based priority approach for the solar GMD and nuclear EMP threats, recognizing that it will be fiscally impracticable to protect everything. Because electromagnetic threat environments are measured in volts per meter, a given system’s vulnerability increases with the length of its connecting lines. Because the electric power grid and long-haul communications network (including telephone and Internet) deliver services on long-lines, these infrastructures are the most vulnerable to EMP and GMD. It is ironic that the infrastructures most vulnerable to EMP and GMD are arguably the most critical to society, not only for day-to-day enterprise and life support, but also for recovery were disasters to occur.

Since a simple measure of risk is the multiplicative product of vulnerability and criticality, the electric power and the long-haul telecommunications networks sit at the top of the risk ranking hierarchy. Thus, attention to the electric power grid and long-haul communications infrastructures would bring major benefits to national resiliency. Of these two, the electric power grid is the arguably the most important – all other infrastructures ride on the electric power system. And the grid is the most essential infrastructure for sustaining population life-support services. And the electric power system operation is brittle and binary, and fails fast and hard. Some essential heavy-duty electric power grid components take months to replace – or years if large numbers are damaged. A primary example is high voltage transformers which are known to irreparably fail during major solar storms and are thus likely to fail during an EMP event. Protection of these large transformers will buy valuable time in restoring the grid and the lifeline services it enables. By contrast, communications networks are more malleable due to their technological diversity and the relative ease of component replacement and repair.

DoD has adopted protective priorities using commercial protective equipment 

We have much to learn from the Department of Defense (DoD) experience in prioritizing and protecting systems since the 1960s. The DoD has prioritized and has protected selected systems against EMP (and, by similitude to E3, GMD effects). DoD places emphasis on protecting its strategic triad and associated command, control, communications, computer, and intelligence (C4I) systems.

Although DoD has been successful in protecting its high priority systems dating back to the Minuteman system procurement in the 1960s, our civilian enterprise remain unprotected. In my experience, the lack of progress in protecting civilian infrastructures to EMP and GMD is due to three main factors:

1. There are prevalent misconceptions about EMP and GMD threats and consequences.
2. Stakeholders are reluctant to act.
3. No single organization is the designated executive agent.