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The Electromagnetic “Triple Threat” and the Critical Infrastructures Revisited


Dr. William A. Radasky, Ph.D., P.E.; This e-mail address is being protected from spambots. You need JavaScript enabled to view it ; Metatech Corporation


In 2009 this author first used the term “triple threat” to describe three severe electromagnetic (EM) threats and the protection methods available to protect commercial installations from the high-altitude electromagnetic pulse (HEMP) produced from a nuclear detonation in space, the intentional electromagnetic pulse (IEMI) produced by electromagnetic weapons used by criminals and terrorists and from severe geomagnetic storms produced by solar activity [1].  This previous paper focused on the fact that while each of these three severe electromagnetic threats are low-probability events, their impacts could be so significant that some attention should be paid to protecting critical commercial assets.

As an aside, the term “triple threat” originally arose in the early 1900’s with respect to American football players who could run, kick and throw the football.  The term has been adapted to other sports and even to business where someone or something has the ability to produce three separate “capabilities”.  It may seem odd to apply this term in this context, but it turns out that these three electromagnetic threats, while being produced in completely different ways, can be protected against in similar fashions [1].

With regard to protection, it is well known that there are other day-to-day “problems” that can occur due to electromagnetic interference (EMI).  Today we have the situation that there are more and more mobile emitters (e.g. cellular phones, tablets, etc.) and additional transmitters operating at higher frequencies such as: WIMAX, RFID, automobile radars, etc.  In addition, each new design of computer equipment must consider some level of EMC immunity from these “new” everyday electromagnetic threats.  As is well known in the EMC community, higher frequencies penetrate small seams (apertures) in equipment cases more easily, allowing higher levels of fields to reach circuit boards.  While EMC board design has advanced over the years, it is necessary to reduce the level of EM fields that can reach a board to make protection solutions more manageable.

For these reasons this author believes that there is a need to consider electromagnetic protection at the building or room level against the high-frequency portion of HEMP and against IEMI, which can also have the benefit of reducing the threat of “everyday” EMI at the same time.  In addition, if this type of protection is considered during the construction phase of a new building or addition, the added cost will be in the few percent range.

One of the most significant advances since 2009 with regard to this “triple threat” occurred on 14 January 2013 at a special seminar hosted by the Institution of Engineering and Technology (IET) in London on 14 January 2013.  This seminar provided an opportunity for researchers in the UK to further their understanding of these threats after the recent enquiry by the House of Commons Defence Committee [3].  Dr. Anthony Wraight, an active member of IEC HPEM standardization activities in the UK, undertook the organization of this seminar, and it was successful in presenting a wide range of technical presentations relating to potential impacts and protection solutions.  This paper will summarize the seminar and provides links for the readers to obtain additional information.

The Seminar Program

Title:  Extreme Electromagnetics – The Triple Threat to the Infrastructures [2]

1.  Welcome and Introduction – Dr. Anthony Wraight

2.  Keynote Address: The Triple Threat to Critical Infrastructures – Dr. William Radasky, Metatech

3.  Space Weather – Nature’s Electromagnetic Hazard Space – Prof. Mike Hapgood, RAL

4.  Geomagnetic Disturbances on the GB Transmission Network – Dr. Andrew Richards, National Grid

5.  Prediction of Extreme Geomagnetically Induced Currents in the UK High-Voltage Network – Dr. Ciarán Beggan, The British Geological Survey

6.  A Survey of Advances in IEMI Source Research – Prof. Edl Schamiloglu, University of New Mexico

7.  Intentional EMI – Experiences from Research, Testing and Vulnerability Assessments in Sweden – Dr Mats Bäckström, Saab AB and Royal Inst. of Technology (KTH)

8.  Potential Implications of the Triple Threat for Critical Infrastructures – Colin Harper, QinetiQ

9.  The STRUCTURES Project (Strategies for The Improvement of critical infrastructureResilience to Electromagnetic attacks) – Dr. John Dawson, University of York

10.  Understanding and Managing the Risk and Resilience of Systems to EMP Events – Andy Titley, CMC and Dr James Kimmance, Parsons Brinckerhoff

11.  Protection of Infrastructure from HEMP and IEMI Disturbances through the Application of Standards – Dr. Richard Hoad, QinetiQ

Discussion of the Presentations

Dr. Anthony Wraight, the seminar organizer, introduced the purpose of the seminar and indicated that the talks were organized in logical blocks beginning with the description of the three electromagnetic threats.  This was followed by 3 talks dealing with the threats of space weather and geomagnetic storms to the British high voltage power grid.  The next two talks dealt with IEMI.  Afterwards there were three talks dealing with implications of these electromagnetic threats and how to develop strategies for protection and resilience.  The final talk of the day dealt with standards activities associated with these threats.

This author was privileged to be the keynote speaker to introduce the electromagnetic characteristics of the three threat environments in terms of how they are generated, their time waveforms, their frequency content and their respective areas of coverage.  I also provided specific information on how each of the three electromagnetic threats could create wide-area power system blackouts and under some circumstances create damage to electric power system components, thus slowing the ability to recover from such an event.  At the end of the talk, I mentioned that the mitigation concepts (including forecasting, protection, and recovery) for these threats are well known, although it is important to design any protection in a cost-effective manner.  Standards have been developed in the IEC for HEMP and IEMI protection, and a later talk in the seminar would discuss this in more detail.

Prof. Mike Hapgood from RAL Space presented an overview of space weather as it is initiated by the Sun, including several fascinating videos of recent solar eruptions.  He also reviewed several historical examples of solar activity and their impacts on Earth; he felt that these events should lead us to a better understanding.  He also made a strong point that the popular media is often not helpful to achieve understanding in that they often hype the possibilities from a solar event before the charged particles arrive at the Earth.  While some earth-bound effects have occurred during recent solar events in this solar cycle, they have been relatively minor.  This leads the public to think that the solar threat is “overblown”.  Unfortunately we know that severe storms have occurred in the past and will occur again someday.  Prof. Hapgood made the point that in spite of difficulties with the popular media, it is important for the scientific community to accurately evaluate an arriving storm to provide situational awareness for the critical infrastructures.

Dr. Andrew Richards from the UK National Grid began his talk with a discussion of the different types of effects that could occur due to the “arrival” of a geomagnetic storm on the Earth.  He then discussed the process of how the time varying geomagnetic fields couple to long high voltage power lines and may, under severe conditions, create problems in large transformers including: flux leakage, voltage instability, distorted a.c. waveforms, and potentially catastrophic damage.  He also summarized the results of a geomagnetic storm study for the National Grid high voltage network, which includes over 1400 transformers.  They classified the risk to each transformer by its design type, age and likelihood of observing a high level of Geomagnetically Induced Current (GIC) under different storm scenarios.  He concluded his talk by summarizing their plans for both operational and engineering mitigation in the future.

Dr. Ciarán Beggan from The British Geological Survey spoke next with a presentation covering the generation of extreme Geomagnetically Induced Currents (GICs) in the UK high-voltage network, and the calculation of these events.  He pointed out that the process of computing the electric fields in the Earth depend primarily on the dH/dt (horizontal component) and the local Earth conductivity.  Their approach was to solve the problem in the frequency domain, which requires Fourier analysis of the time-dependent magnetic field fluctuations.  The modeling of the UK power grid was described in terms of a preliminary model and a more recent detailed computational model.  Using these models several extreme cases of possible future storms were considered from a probabilistic perspective.  He also described the possible effects of the late-time (E3) portion of the HEMP, and concluded that due to its shorter pulse width, it was more likely to create a rapid power blackout instead of creating damage to many transformers.

The next set of talks dealt with IEMI, and Prof. Edl Schamiloglu spoke about advances in Intentional Electromagnetic Interference (IEMI) research.  He surveyed narrowband sources, which produce high power microwaves (HPM) and could power IEMI weapons.  He discussed the characteristics of different types of narrowband sources in terms of their peak power vs. their frequency of operation.  In addition, he discussed the historical increase of peak power capability from these types of sources from 1940 to the present.  The last portion of his talk was about more recent developments that have resulted in more compact sources, which are of concern with regard to the IEMI threat to commercial facilities.

Dr. Mats Bäckström next presented the background of the Intentional Electromagnetic Interference (IEMI) threat against the civilian infrastructures, including an overview of the comprehensive R&D on Intentional EMI that has been carried out within the Swedish defence community over the past 25 years.  He spoke about both radiated and conducted threats including narrowband and wideband waveforms.  In addition he discussed the problems of front door (e.g. antenna in-band) and back door (through unintentional paths) coupling interactions.  He also reviewed some of the susceptibility studies performed in Sweden over the years to evaluate the performance of typical commercial electronics.  In his concluding remarks he recommended that in the future the community should study the impacts of IEMI on complete systems, not only on particular pieces of equipment.

The next three talks covered the implications of these intense EM fields, and Mr. Colin Harper of QinetiQ began this discussion by describing how to evaluate the Triple threat against the functioning of modern societies.  He reviewed some of the work performed by the US EMP Commission and several US Congressional Bills that have dealt with these severe EM threats, and he also discussed documented cases of IEMI attacks on commercial systems.  He continued to mention the fact that the Smart Grid could present itself as an “easier target” for criminals due to the complex communications capability required for its operation.  In the last part of his talk he felt that several factors needed to be considered together including the technology capability of IEMI sources, their costs, and the types of effects that could result from their use.  This information is needed in order to define the proper level of protection for each situation.

Dr. John Dawson from the University of York next gave a presentation covering a new EU project on Strategies for The impRovement of critical infrastrUCTUre Resilience to Electromagnetic attackS (STRUCTURES).  This is a 3-year project that began in July 2012 and is to be completed by June 2015.  The project has 12 partners and several end users participating.  The project objectives are to: bring together existing research in IEMI; analyze risks to the critical infrastructures; evaluate protection and detection methods; produce guidelines for end users and policy makers, and interact with end users during the project.

Mr. Andrew Titley and Dr. James Kimmance from CMC and Parsons Brinckerhoff, respectively, presented their views of how to assess and manage severe risks to society.  They pointed out that it is crucial to understand the nature, likelihood, consequences and uncertainties to perform a proper evaluation of the risks for a particular threat.  They discussed the term, “emergent risks” which are different from those for which we can readily identify the frequency and consequence.  The term “emerging” is used because these risks are related to new technologies and new dependencies on society.  These emerging risks are also characterized by the absence of data or statistics, creating a difficulty in estimating the frequency and magnitudes of the consequences if they occur.  In addition they discussed the important role of uncertainty and how it can affect our ability to evaluate the risks.  The remainder of their talk covered how to put the various triple threats into the proper context for the evaluation of risk.

Dr. Richard Hoad of QinetiQ provided the last presentation of the day covering the standardization work accomplished in several international standards organizations.  The largest number of standards covering:  the threat waveforms associated with HEMP and IEMI, their effects on equipment and systems, test methods to evaluate hardness or vulnerability, and protection methods have been prepared by the International Electrotechnical Commission (IEC) in Geneva.  Dr. Hoad is the Secretary of IEC SC 77C, which has developed these standards.  In addition, he mentioned the work of ITU-T in terms of developing protection standards for telecommunications facilities against the threats of HEMP and IEMI and also the work of Cigré to evaluate the threat of IEMI against the control electronics in high voltage power stations.  It was emphasized that the electromagnetics community knows how to design protection against these extreme electromagnetic threats, but it is necessary to evaluate the requirements and levels of protection required.


It is important to note that while the subject of the electromagnetic triple threat has been discussed for many years, this one-day seminar in London was successful in updating the work underway in the UK and several other countries in a technical fashion.  It is hoped that those who have interest will download and read the presentations to further their understanding (go first to the link referenced below in [2]).  This author hopes that this type of seminar can be repeated in the future to gauge the progress being made regarding this important problem.


[1] W. Radasky, “Protection of commercial installations from the “triple threat” of HEMP, IEMI, and severe geomagnetic storms,” Interference Technology EMC Directory and Design Guide 2009, April 2009.


[3] House of Commons Defence Committee, “Developing Threats: Electro-Magnetic Pulses (EMP),” HC1552, 22 February 2012.  Link: