E-Bombs: The Allure and Peril of High-Power Microwave Weapons

E-bombs might be the most dangerous WMDs of our modern world.
Christopher McFadden

Good news! For those worried about the imminent take over of AI and robots, humans may have an "Ace card" up our sleeves — the E-bomb. These electronic weapons of mass destruction might just be the trick for knocking out any want-to-be Skynet in the near future. 

Likely, these bombs may just represent one of the most serious threats to our modern tech-dominated lives after the nuclear bomb. Whether by belligerent nations or terrorists, such bombs could be used to wreak havoc without a bullet ever taking flight. 

Prepare to be shocked.

What is an E-bomb?

An electromagnetic bomb, or E-bomb for short, is a device that generates a high-power electromagnetic pulse and/or high-power microwave pulse, that is capable of severely damaging, or rendering completely useless, electronic devices within its pulse radius. Similar in concept to a conventional high-explosive bomb, the damage caused is not from the bomb's physical ability to destroy a target object, but rather its devastating effect on electronic devices and networks. 

e-bombs electrical WMDs
Source: photographymontreal/Flickr

While few E-bombs currently exist (as far as we know) these kinds of bombs could prove devastating to nations that are heavily reliant on electrical and digital infrastructures. In fact, a form of NNEMP (non-nuclear E-bomb) was reportedly used to disable Saddam Hussein's propaganda network during the 2003 Invasion of Iraq. 

Theoretically, such bombs could be used to disable a target nation's digital infrastructure and economy, potentially causing internal unrest, severely damaging their ability to wage war, and ultimately potentially create a societal collapse. 

Similar EMP bursts are often observed during nuclear weapon detonations that propagate rapidly fluctuating electric and magnetic fields resulting in damaging current and voltage surges. Although, the term E-bomb often refers to non-nuclear EMP weapons (NNEMP). 

EMP blasts can also be observed in nature, often associated with lightning storms and solar storm events. However, the impacts of the former tend to be more localized and small-scale. Solar storms, on the other hand, could arguably be more severe than a theoretical E-bomb attack. 

These bombs potentially offer a greater threat to modern nations than atomic weapons, as digital hardware is now all-pervasive and increasingly critical to many developed economies. With drives for ever-more increased interconnectivity, like the Internet of Things, the potential threat these weapons would offer in the future is only set to increase exponentially. 

e-bomb explosion
Source: aimee rivers/Flickr

With the increasing reliance on digital technology in military assets, such bombs could also prove devastating to naval, airborne, and ground-based military targets or communications. 

While the threat these weapons pose might sound fanciful, some experts are so worried about them that they have been warning about the potential danger for many years. Unfortunately, these concerns have all-too-often fallen on deaf ears.

Some have even gone as far as to say that we may well see a real E-bomb attack within the next decade or so. 

How do E-bombs work?

In our digitally-interconnected modern world, weapons like E-bombs could prove to be very dangerous indeed. One of the main reasons for this is the proliferation of electronic machinery and digital hardware around the world throughout the 20th and 21st centuries. 

Digital infrastructure exists everywhere today in many nations, with applications varying from handheld devices, domestic or office equipment, transportation (like smart cars), production, health, to power plants. While the benefits of such digital integration are incalculable, the electronics used in any digital infrastructure could be a very serious chink in the armor of a nation's security with regards to E-bomb vulnerability. This could include infrastructure systems such as nuclear power plants, and water and sewer management plants.

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Any exposure of these systems, be it to transient or radiant frequency, in excess of their specified voltage limit could result in very serious damage. 

E-bombs friendly
Not all EMp devices are hostile. This "friendly" EM Environment Simulator is used to test the effects of EMP pulses on electronic devices. Source: Sandia Labs/Fliclr

For example, most electronic devices will break down through a number of over-voltage-related mechanisms. An attack from a large enough E-bomb, or set of smaller ones could cause transient dropouts,  lead to longer-term "wounds" in the system, or even end up with a complete electrical failure. A big enough surge could not only burn out semiconductor devices, but could melt wiring, fry batteries, and even explode transformers. All within the weapon's so-called "lethal footprint".

This is effectively the EMP "blast radius" of the E-bomb. EMP blasts tend to occur over three discrete phases. First seen in nuclear detonations, these are:

1. The initial near-instantaneous pulse (sometimes referred to as the "E1" phase).

2. A subsequent high-amplitude phase, aka the "E2" pulse.

3. And, the final lower-amplitude (but still damaging) "E3" pulse.

You can liken an E-bomb to a device that cracks a dyke or dam allowing an uncontrolled flood of electricity (the water being held back by the dyke) in its wake.

The first phase ("E1") causes most of the damage by inducing a voltage in electronic conductors beyond their safety tolerances (i.e. it cracks the dyke). The next phase ("E2") acts in a similar fashion to a lightning strike and would likely be the least damaging, assuming lighting protection is not compromised from the "E1" pulse. 

EMP bombs nukes
Similar EMP pulses are also generated by nuclear explosions. Source: Burnt Pineapple Productions / Flickr

The third, and final, "E3" pulse can last from seconds to minutes and occurs when the fireball (if explosively generated) from the initial blast temporarily warps the Earth's magnetic field. This is the phase that could cause the highly damaging cascading damage to digital infrastructures (more on this later). 

Exposure to massive bursts of EM energy can cause dielectric insulators (like MOSFETs, which are metal-oxide-semiconductor field-effect transistors) to break down or leak, and reverse-biased junctions can suffer avalanche breakdowns. Once things like MOSFETs are compromised, they are no longer able to switch/control current flow and electrons are able to freely move between the source (power supply) and drain. 

Another problem is the consequential build-up of heat in electronics too. According to Ohm's law, higher voltages tend to increase the amount of current in electrical circuits leading to a chain reaction in heat generation because of a semiconductor's negative temperature coefficient. This heat, while likely not high enough to melt the semiconductors, will probably be enough to melt thin metal wires and epoxy, resulting in burnouts. 

Grid or battery-powered devices often require very little energy to actually initiate this kind of catastrophic failure.

After the initial EMP pulse and with insulators damaged, the power supply (be it battery or mains), can flow unimpeded wreaking havoc in electrical circuitry. 

For this reason, one of the most important potential impacts from E-bomb attacks is the cascading damage caused within a nation's digital infrastructure. The failure of one device in the system, could, potentially, trigger an overload in another, and then another, so on and so forth all the way along the network.

For large interconnected systems, like those in developed nations, E-bomb attacks could lead to a total power grid, and/or digital network, collapse. 

This kind of cascading effect would lead to things like switch mode power supply (SMPS) blowouts that will, in turn, produce electrical spikes in the power grid. This could conceivably cause hundreds of thousands of these to fail near-simultaneously within the peripheral areas to the E-bombs initial "lethal footprint". 

As you can imagine, this would be devastating and potentially a very efficient way to severely cripple an enemy nation. 

Which countries have E-bombs?

The short answer is that we don't really know. While it is known that countries like the US, Russia, EU member states, China, and possibly North Korea have been conducting research into the weaponization of such technology, we can not be entirely sure how much progress has been made. 

That being said, and as we previously mentioned, the US appears to have a working example, if reports of their use during the 2003 Invasion of Iraq are correct. 

One disconcerting thing to note is that anyone with sufficient knowledge of how a nuclear or conventional bomb works, and access to the required materials, could conceivably make one relatively easily. 

However, this should also bring some form of comfort, as any research team would need to have sufficient physicists with a working knowledge of how to make FCGs (flux compression generators) and vircators (VIRtual CAthode oscillaTOR). 

examples of theorized e-bombs
Examples of theorized E-bombs. Source: ausairpower

With regards to the equipment and components needed, much of what would be required have existed since the 1950s or so. If someone could get accurate enough schematics, or devise their own, a working E-Bomb could be built for a few hundred to a couple of thousand dollars in uncontrolled materials. 

For example, such devices often require access to C4, Semtex, or other high-velocity castable explosives that are readily available. 

What kind of electromagnetic weapons are there?

You might be surprised to hear that there are actually quite a few of them. However, most generally tend to fall into several types depending on their means of deployment and spectral coverage. 

It is important to note, that various electromagnetic pulse generating equipment is also used for scientific and more benign purposes also. 

For their effect, be it steady-state or transient effect, the former tends to consist of things like beam weapons, with the latter one-shot devices like E-bombs. Once activated, or detonated, the spectral coverage released then tends to fall into either wideband or narrowband, high or low frequency, and emitted power. 

According to one expert, Carlo Kopp, "a wideband low-frequency low power one-shot weapon might be a submunition for a cluster bomb using a rare earth magnet with a high explosive jacket, while a wideband high-frequency high power repetitively pulsed weapon might be a Marx bank driven Landecker Ring mounted in the focal area of a parabolic dish antenna."

e-bombs damage
E-bomb attacks would seriously damage electronic circuits and networks. Source: Rick Kimpel/Flickr

Kopp also happens to be the person who first coined the term "E-bomb" back in the 1990s.

This term has been used to describe both something like a high-altitude, nuclear Electro-Magnetic Pulse (EMP) bomb and has been applied to smaller, non-nuclear devices based on something called a Flux Compression Generator (FCG).

This device, first demonstrated by Max Fowler in the 1940s, uses a fast explosive to rapidly compress a magnetic field, transferring energy from the explosive into the magnetic field. During operation, the FGC would be destroyed, but it would emit enormous amounts of electrical current in the process. If enough of them were detonated in sequence, this current can be amplified into peak power levels of the order of TeraWatts to tens of TeraWatts.

These devices would produce a direct low-frequency wideband effect or could be used as a one-shot pulse power supply for a High Power Microwave (HPM) tube such as a Virtual Cathode Oscillator (Vircator). A vircator is a device used to focus the energy released from an FGC over hundreds of meters, or more, away a bit like the reflector on a torch or car headlight. 

What are the limitations of E-bombs?

The main limitation of E-bombs, like any other conventional bomb, is their means of delivery to a target. If launched from an aircraft, their effectiveness is completely reliant on the delivery platform's ability to reach and deploy the weapon.

If intended to be delivered by smaller fighter-bomber jets, for example, the size of the E-bomb will be limited. Delivery by larger intercontinental ballistic missiles (ICBM) would offer the potential for higher payloads, but would also drastically increase the cost per unit. 

Interestingly, another limitation of E-bombs is also their intended target. If older electronics are used, for example, thermionic technology rather than solid-state, the target would have some resilience to an E-bomb attack. 

Some other targets, like radar installations, may also appear to have been unaffected if they continue to radiate radar signals after an attack. While receiving equipment will likely have been knocked out of action, this would not be obvious to an observer. Shutting off such systems prior to an attack could also be used to "fool" attacking forces into thinking an attack has been successful too. 

Can digital infrastructure be protected from E-bombs?

Are you scared yet? The good news is that while E-bombs are potentially incredibly destructive devices, there are things that can be done to protect against them — electromagnetic hardening of digital infrastructure. 

This process involves the "hardening" of digital equipment and power supplies. One example is to replace all metallic cabling (especially old copper wiring) with optical fiber alternatives in networks. Others include installing protection devices into antenna feeds, and grid power interfaces. 

E-bombs could knock out power grids. Source: Daniel Arrhakis/Flickr

Other options include enclosing critical electronic systems within conductive enclosures, like a Faraday cage. However, systems inside the cage would still need connectivity or power from outside it, which can still present a vulnerability. 

Under such circumstances, electromagnetic arresting devices could prove incredibly useful. 

While homeowners can do this to their own homes to some extent, it is important to note it is more critical to protect the main grid and telecom networks. A protected, working computer will be practically useless with no grid power or internet connection should an E-bomb be detonated.

Retroactive hardening of this kind would be costly, and time-consuming, for most developed nations, but if experts in the field are correct, E-bombs are quite literally, a ticking time bomb. It is not a matter of if, but when, an E-bomb attack is seen. 

If decision-makers in governments can be convinced to take the problem seriously, rather than treat it as an esoteric or ethereal fantasy, only then can nations fortify their electronic defenses. Even if they are never needed. 

If newer devices and installations could be "hardened" from the outset, this will save time and shouldn't add that much extra cost (estimates range from 10 to 20%) at the point of purchase or commission. 

Even if E-bombs never really materialize as a potential national security threat in the near term, the hardening of our digital infrastructures might be a good idea anyway. After all, concerns about acts of nature like Coronal Mass Ejections, and other solar events, have been shown to disable electrical systems here on Earth. 

Two birds with one stone, if you like. So far we've been lucky, but large future solar storm events are an inevitability.