Non-nuclear EMP


in Bombs and rockets, Geek stuff, Science, Security

Several fictional portrayals have drawn attention to the possibility of an electromagnetic pulse (EMP) being used as a weapon, capable of disabling or destroying electronic equipment over a wide area. Such pulses can be created by detonating nuclear weapons at high altitude, though doing so in a war would provoke international outrage. To get around that, the United States and possibly others have developed non-nuclear EMP generators:

One such weapon uses a small charge of explosive to ram an armature down the axis of a current-carrying coil, squeezing its magnetic field so violently in the process that it emits a powerful burst of electromagnetic energy over distances of several hundred metres. Another type employs a Marx generator (a machine used for simulating lightning strikes) to dump a large electrical charge stored in a bank of capacitors into a specially shaped antenna.

American defence forces have converted a number of cruise missiles to function as non-nuclear EMP generators. Apparently, cars parked up to 300 metres away have had their alternators, ignition coils and engine controls disabled this way. Such e-weapons are said to have been used in Kosovo, the Persian Gulf and Afghanistan.

Intriguingly, a pair of such devices has recently broken cover. The Counter-Electronics High-Power Microwave Advanced Missile Project (CHAMP) is an unmanned aircraft fitted with a microwave pulse generator—presumably for disrupting enemy communications. The Pentagon has also announced that it is deploying an electromagnetic weapon, believed to be called Max Power, for detonating roadside bombs and disabling enemy vehicles. Both CHAMP and Max Power mimic the electromagnetic pulse of a nuclear explosion—albeit over a narrowly focused area and without the geomagnetic effect.

Such weapons could be useful for reducing civilian casualties in war, particularly in situations where military targets are located in civilian areas. For example, if a state put an air defence RADAR station in a residential area, an EMP weapon could disable it at lesser risk to the civilian population, compared with conventional munitions.

Apparently, electromagnetic pulses can also be used to punch holes through steel for industrial purposes.

{ 18 comments… read them below or add one }

R.K. September 7, 2010 at 9:04 am

Such weapons could be useful for reducing civilian casualties in war, particularly in situations where military targets are located in civilian areas.

Destroying all the electronics in the area might not cause immediate civilian casualties, but it would cause at least some in the long term by disrupting critical infrastructure like water treatment plants and hospitals.

Milan September 8, 2010 at 11:36 am

I was thinking of the conventional sort of EMP generators described in the linked article, not the city-wide nuclear EMP devices that would cause the kind of collateral damage you highlight.

. September 13, 2010 at 3:23 pm

“The effects of an EMP — both tactical and strategic — have the potential to be quite significant, but they are also quite uncertain. Such widespread effects can be created during a high-altitude nuclear detonation (generally above 30 kilometers, or about 18 miles). This widespread EMP effect is referred to as high-altitude EMP or HEMP. Test data from actual high-altitude nuclear explosions is extremely limited. Only the United States and the Soviet Union conducted atmospheric nuclear tests above 20 kilometers and, combined, they carried out fewer than 20 actual tests.

As late as 1962 — a year before the Partial Test Ban Treaty went into effect, prohibiting its signatories from conducting aboveground test detonations and ending atmospheric tests — scientists were surprised by the HEMP effect. During a July 1962 atmospheric nuclear test called “Starfish Prime,” which took place 400 kilometers above Johnston Island in the Pacific, electrical and electronic systems were damaged in Hawaii, some 1,400 kilometers away. The Starfish Prime test was not designed to study HEMP, and the effect on Hawaii, which was so far from ground zero, startled U.S. scientists.

Non-nuclear devices that create an EMP-like effect, such as high-power microwave (HPM) devices, have been developed by several countries, including the United States. The most capable of these devices are thought to have significant tactical utility and more powerful variants may be able to achieve effects more than a kilometer away. But at the present time, such weapons do not appear to be able to create an EMP effect large enough to affect a city, much less an entire country. Because of this, we will confine our discussion of the EMP threat to HEMP caused by a nuclear detonation, which also happens to be the most prevalent scenario appearing in the media.”

Vance January 14, 2011 at 1:58 pm

There has been a lot of discussion recently about Chinese military capabilities and the startling improvements/innovations they’ve made within the past 5-10 years.

One of the more interesting new weapons making the news circuits concernes the DF21 ASBM (anti ship ballistic missle). When fully operational, it is believed that this missle would be able to accurately target and strike a moving aircraft carrier 1,300 miles off the Chinese coast.

Many analysts are quoted by journalists as saying that the probability of any missle hitting a moving carrier is rather remote. After reading some of this material regarding non-nuclear EMP weapons, I’m not so sure the missle would actually have to strike it’s target to be effective.

Based on what I’ve read, if a DF21 armed with a non-nuclear EMP warhead were to detonate within a mile of a carrier, wouldn’t it be “all ahead stop”?

Milan January 16, 2011 at 9:48 pm

I know the American navy is particularly nervous about emerging threats to carrier battle groups, including supercavitating torpedoes.

Vance January 17, 2011 at 8:45 am

I suppose there’s no shortage of emerging threats to the US Navy, yet I don’t know that I’d have included the supercavitating torpedo as one of them simply because it is not a new weapon, nor does it have a tremendous range (~4 miles).

Getting a shot off at a carrier within that range would be difficult and almost certainly suicidal. Now, picking off an escort ship would present a much more managable challenge, however the chances of the attacker’s survival remains dismal.

Granted, suicide missions are all the rage among American enemies these days, but such an attack would almost certainly be state sponsored due to it’s cost. A NK minisub, for example would NOT be able to attemt such a feat because the torpedo (at 27′) is almost longer than the craft itself. In short, the attacking craft would have to be of sufficient size to carry out the mission, meaning that it is likely cost prohibitive to send such an asset on a suicide mission.

Thank you, Milan, for inspiring me to research supercavitation! I knew very little about it before your post.

Milan January 18, 2011 at 11:32 pm

China is also developing one or more type(s) of anti-ship ballistic missile.

Some related articles:

China: Fielding a New Anti-Ship Capability

Part 2: China’s Plan for a Blue-Water Fleet

Vance January 19, 2011 at 8:15 am


Thanks for forwarding the links to the related articles. They are informative and well written.

So far as I’m aware, the DF21d (the latest variant on the DengFao – eastern wind – missle program) is the only true ASBM system in existence, although it is not operational at this time.

Other anti-ship weapon systems are employed by the Chinese and other nations as well. The PLA has exported some of these systems to other countries (such as the silkworm shore or sea based missle to Iran, India, Brazil and North Korea). What sets these apart from an ASBM is the lack of a ballistic quality. The DF21d leaves the earth’s atmosphere and releases an unpowered armed reentry vehicle, much like an ICBM or medium range nuclear ballistic missle. The other noted systems remain in the atmosphere and rely on a guidance system and motor to to deliver them to their target.

The US was experimenting with an ASBM system in the 1980’s, but scrapped the program when the Soviet Union dissolved.

From some accounts I’ve read, the DF21d reentry vehicle uses a guidance system almost identicle to the US Pershing II meduim range ballistic missle. Although a Pershing II is said to be able to hit a small automobile from 1,500 miles away, that automobile must be stationary. The DF21d aims to overcome this limitation. This is what would make an operational ASBM truly remarkable.

. January 19, 2011 at 6:22 pm

A chief Pentagon concern is China’s development and purchase of missiles making it more difficult for American aircraft carriers to operate in the western Pacific. The missiles include the DF-21D, a medium-range ballistic missile. In December the head of the United States Pacific Command, Admiral Robert Willard, said that the DF-21D had reached “initial operating capability”. The weapon would use data fed by satellites and other surveillance devices to home in on a moving carrier more than 1,500km (930 miles) offshore. Pentagon officials say work on the DF-21D (which would be the first such missile deployed by any army) and the J-20 fighter has progressed faster than they had expected. China is also reportedly close to deploying its first aircraft carrier, a refitted ex-Soviet ship. It may be a long time before any of these can challenge America’s military domination of the Pacific, but they may constrain what the United States can do in waters around China—and Taiwan.

Of the three developments, the DF-21D is the greatest worry to the Americans. Their Aegis missile defence system, deployed to protect American carrier groups, is designed to track a missile’s trajectory from launch. The DF-21D is supposed to be able to change course in mid-flight so as to evade Aegis interceptors. Lockheed Martin, which makes the Aegis system, is trying to come up with a fix. As for the J-20, some scepticism is in order. Although the design has stealth characteristics, its large nose canards, big engine intakes and fixed-thrust nozzles suggest the Chinese have a long way to go before they have a plane that is close to America’s F-22—call them the PLA’s “three shames”.

Milan January 19, 2011 at 6:33 pm

Although a Pershing II is said to be able to hit a small automobile from 1,500 miles away, that automobile must be stationary. The DF21d aims to overcome this limitation. This is what would make an operational ASBM truly remarkable.

Is it really that much harder to hit an aircraft carrier? The Nimitz-class supercarriers have a speed of 56+ km/h according to Wikipedia. If the terminal phase of a ballistic missile only lasts a few seconds, a carrier can’t move all that far, can it?

Is there some technical reason why a large target moving on a relatively slow and predictable course is much harder to hit than a stationary one?

Vance January 19, 2011 at 7:12 pm

Excellent point and question, Milan.

Perhaps a good way to answer this (and bring the discussion back to EMP weapons) would be to review what we know about existing technologies.

For example, a missle launch (from the Chinese mainland in this case) will be detected by American satellites before an appreciable altitude is reached. This intelligence is communicated to the carrier in real time, so knowledge of the launch occurs much sooner than may be otherwise presumed.

The missile requires approximately 10 minutes from launch to impact to traverse the 900+ miles that is thought to be it’s maximum effective range. This means that a carrier moving at 30 knots will travel ~5.3 miles over the course of the missle’s flight.

If the ship was unaware of the launch, your premise regarding the ship’s predictable course and speed would put an effective end to this conversation. Yet, the ship is actually aware of a potential attack almost as soon as it’s launched meaning that evasive action is all but certain.

Now, back to EMP’s…even the Chinese have noted that they would send a volley of these weapons – presumably to account for evasive action taken by the carrier. The conclusion I’ve reached here is that they don’t expect a ‘hit’ as it were. Understanding that a 1,500 lb conventional warhead is unlikely to sink a ship of a carrier’s size and design, the Chinese have opted for the next best alternative. Bracketing the carrier with EMP warheads is likely to have the effect of giving the carrier 4 flat tires – in other words, marooned. A disabled carrier is not a threat, and suddenly has become a stationary target.

This is the scenario I had in mind when I registered my original post.

While I enjoy the conversation, I should offer my apologies to those who might be ‘concerned’ about the departure from the EMP discussion.

Once again Milan, thank you for the thought provoking discourse.

R.K. January 19, 2011 at 11:34 pm

Carriers probably don’t travel at full speed most of the time, when they are in battle groups. They probably go as slowly as their non-nuclear support vessels do.

Vance January 20, 2011 at 12:15 pm

You raise a fair point, RK. Although the Strike Group ships (Ticonderoga CG, Arleigh Burke DDG and Los Angeles SSN) can easily maintain a 30+ knot pace, the oiler and ordinance ships likely couldn’t.

I’m not sure that really matters, though. The idea of evasion in a DF21 attack scenario is to stymie the targeter’s calculation of course and speed. In this respect, the strike group might proceed at a much slower pace (or even begin a full stop) when a launch was detected. Doing so would have the same effect as increasing speed in that the target course/speed calculation is no longer accurate.

R.K. January 20, 2011 at 5:53 pm

I suppose one relevant question is which phase of the DF21’s trajectory is the last one where course corrections can be made. If it can’t steer at all on the way down, that might explain why hitting moving targets is such a challenge.

Vance January 20, 2011 at 6:14 pm

Right you are, RK. The missle’s warhead has guidance (and I do use that term rather loosely) until just before it reaches apogee. After that point, the final course corrections provided by the targeter will define the warhead’s final path.

Bear in mind that the final descent of the projectile consumes the greater amount of the total flight time because of the reentry phase.

This means that I must agree with your premise that there is a tremendous degree of technical difficulty when faced with the challenge of successfully targeting a moving object with a ballistic missle.

Thank you for making the point so succinctly.

. January 21, 2011 at 8:05 am

Rumors and signs of the rising influence of the military establishment in China have emerged over the past few years. Since the 1980s, China has focused on and invested in a major reorientation of its military from a massive land army focused on territorial defense to one that emphasizes naval and air capabilities to protect China’s interests in the East and South China seas and beyond into the western Pacific. This has included expanding China’s reach and a focus on anti-access and area-denial capabilities, with accelerated development in this arena in recent years.

Some systems, like the DF-21D anti-ship ballistic missile, are uniquely tailored to countering the U.S. Navy. Others, like an expanding and more aggressive Ocean and Fisheries Administration, is directed more at China’s neighbors in the South and East China seas, and at asserting China’s claims to these waters.

This change in focus is driven by three factors. First, China sees its land borders as being fairly well locked down, with its buffer territories largely under control, but the maritime border is a vulnerability — a particular concern for a trade-based economy. Second, as China’s economy has rapidly expanded, so has Beijing’s dependence on far-flung sources of natural resources and emerging markets. This drives the government and military to look at protection of sea-lanes, often far from China’s shores. Third, the military leadership is using these concerns to increase its own role in internal decision-making. The more dependent China is on places far from its borders, the more the military can make the case that it is the only entity with both the intelligence and the understanding to provide the necessary strategic advice and perspective to China’s civilian leadership.

There is also the issue of a modernizing military looking out for itself, battling for its share of China’s budget and economic pie. A key part of former Chinese President Jiang Zemin’s fundamental military reforms was stripping the military of much of its business empire. At the time, the state — while funding the military — assumed that military-run industry would supplement the defense budget. In short, the military ran industries, and the profits were used to support local and regional defense needs. That kept the official state military budget down and encouraged enterprising commanders to contribute to China’s economic growth.

. October 13, 2011 at 8:42 pm

Electromagnetic weapons
Frying tonight
Warfare is changing as weapons that destroy electronics, not people, are deployed on the field of battle

. October 13, 2011 at 8:43 pm

“Many electromagnetic weapons do, indeed, look like radars, at least to non-expert eyes. America’s air force is developing a range of them based on a type of radar called an active electronically scanned array (AESA). When acting as a normal radar, an AESA broadcasts its microwaves over a wide area. At the touch of a button, however, all of its energy can be focused onto a single point. If that point coincides with an incoming missile or aircraft, the target’s electronics will be zapped.

In the case of the F-35, then, this sort of electromagnetic artillery is mainly defensive. But another plane, the Boeing Growler, uses electromagnetics as offensive weapons. The Growler, which first saw action in Iraq in 2010 and has been extensively (though discreetly) deployed during the NATO air war against Colonel Qaddafi’s forces in Libya, is a souped-up version of the Super Hornet. It is fitted with five pods: two under each wing and one under the fuselage. Some pods contain AESAs or similar electromagnetic weapons. Others have eavesdropping equipment inside them. In combination, the pods can be used either to spy on enemy communications or to destroy them; to suppress anti-aircraft fire; to disable the electronics of ground vehicles; and to make life so hazardous for enemy aircraft that they dare not fly (and probably to shoot them down electronically, too, though no one will confirm this).”

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