EMPs above the earth's surface

China tests a new EMP weaponAn EMP, or electromagnetic pulse, is a fascinating phenomenon. Caused by a rapid acceleration of charged particles travelling at the speed of light, an EMP can easily disable electronics including household electrical equipment, automobiles, and even electric utility power grids.

Inherent properties of electronic components make this possible.  Electronic circuits act like antennas and “receive” the EMP which transfers energy quickly producing a heat surge that damages or destroys sensitive electronic components. An EMP’s ability to quietly and invisibly disable electronic components makes them an excellent weapon for electronic warfare tactics.

Causes and types of EMPs (electromagnetic pulses)

There are three types of EMPs and each type can be produced in a variety of ways. EMP pulses categorized as “E1” pulses are the quickest, highest frequency EMP pulse. They are extremely intense and produce an electromagnetic field that induces very high voltages, high enough to damage many electronic components (the EMP causes the device’s voltage capacity to be exceeded).

EMP pulses classified as E2 are lower frequency than E1 pulses and are very similar to the energy wave released in a lightning strike. As such, they are not as risky since many modern-day devices are designed to afford at least some protection against lightning strikes.

E3 pulses are the slowest type of EMP pulse and are very different from E1 and E2. They may last from tens to hundreds of seconds.  By producing a DC-like current, they do damage to electrical infrastructures such as transformers and power grid components. Since they are often caused by the Sun, they are indeed the riskiest EMP.

EMPs are produced in a variety of ways. Cosmic EMPs (or solar EMP) are caused by coronal mass ejections (CMEs) from the Sun and are typically classified as E3 pulses. Explosive devices, such as nuclear bombs, create gamma rays which hit nearby atoms knocking away electrons and resulting in a radio pulse. These types of EMPs are typically classified as E1 pulses but bombs can also produce E2 and E3 pulses. Finally, purposed engineered EMP devices, often referred to as non-nuclear electromagnetic pulses (NNEMP) can create EMP pulses of all three types which makes them particularly catastrophic.

How to create a EMP (electromagnetic pulse) generating device

Standard disclaimer/warning: EMP generator devices are surprisingly easy to create. However, the most common design uses high-voltage capacitors which can make construction a dangerous proposition. You can easily be shocked or killed by an EMP device. The information provided in this article is for informational purposes only. Injury or property damage may result from creation or use of an EMP device.

Given that an EMP is nothing more than a quick burst of electromagnetic energy, to construct a working EMP device we need (1) the means to create, strengthen and focus the electromagnetic wave and (2), the means to produce a quick burst of high energy required to create the EMP pulse.

To create and strengthen the electromagnetic wave, all we need is a metal coil (called an induction coil or spark coil) which acts as an antenna (i.e. it converts electrical energy into waves).

To produce the explosive burst of energy we have multiple options. Firstly, we could use electronic capacitors (like found in a camera flash’s charging mechanism) which store and release electrical charges in explosive bursts, to create the quick burst of energy required to generate the pulse.

Alternatively, we can also use explosives to accelerate magnets through a coil in order to produce a EMP pulse.

Make an EMP device using a disposable camera

Disposbale camera circuit used to create a EMP generator deviceThe easiest EMP device to construct in the Camera EMP device.  To make an EMP device out of a camera, you’ll need a disposable camera, iron rod, copper wire, and a non-metal rod (for the insulated “handle”).

  1. Beginning on one end of the metal rod, wrap the copper wire around the metal rod to form a tight-wound copper coil around the rod (this creates an electromagnet). The thicker the copper wire, the more powerful the resulting EMP (large EMP devices may even use copper tubing instead of wire). Leave a length of wire on both ends for attaching to the camera’s capacitor.
  2. Disassemble a disposable camera and remove the charging circuit board. All we really need is the capacitor (it looks like a thick firecracker) but leaving the board intact lets us utilize the board’s battery holder and capacitor charging components.
  3. Attach one of the two wires from the copper coil to the camera’s capacitor component (glue or solder if desired).
    Warning: Capacitors work like extremely powerful batteries. They store an electrical charge and release it in a quick, powerful burst. They are often used in camera flashers, Tasers, bug zappers, barbeque lighters, and many other electronic devices (as a result, any of these devices could have been used to create our EMP device). If the capacitor has not been discharged before handling, or the battery has not been removed, it can create a shock strong enough to knock you off your feet.
  4. Optional: Attach the non-metal rod to the metal rod using tape. Place one end of the metal rod aligned with the end of the non-metal rod so the ends overlap a few inches, then tape the two together. The non-metal rod provides nothing for the EMP device’s design and simply serves as an insulated handle to grip the EMP device without getting shocked.  Alternatively, you may skip this step and simply place the EMP device near your target.
  5. Test the EMP generator against an electronic device (a cheap calculator or electronic toy works well as a target). Place the EMP device near the target (but not touching it). To fire the EMP, you can either connect the other end of the coil wire to the capacitor or if you left the capacitor on the circuit board, simply push the camera’s power button to fire it.

This device will have an effective distance of a few feet.

To recharge the capacitor, insert the battery pack back onto the circuit board. The capacitor will likely make a high-pitch whining noise when charging.

Make an EMP device by thrusting magnets through a coil

Illustration showing the operation of a chemical explosive driven EMP bombWith this type of EMP device, instead of using a capacitor to produce the quick burst of energy, we fire a set of magnets through a coil to produce an instant EMP. We’ll need a firecracker, hollow iron rod (big enough to hold the firecracker), copper wire, and neodymium magnets (the most widely used type of rare-earth magnets).

  1. As described in the “disposable camera EMP device” above, wrap the hollow iron rod tightly with copper wire.
  2. Attach the ends of the copper writes to two neodymium magnets (solder or wrap the wire around the magnets).
  3. Glue the magnets to each opposing end of the firecracker.
  4. Place the firecracker inside the hollow rod, as close to center as possible, and light it.

The firecracker explosion will blow the magnets out of the rod at a very high velocity. As the magnets move through the coil, they will produce an intense surge of energy and thus, generate an EMP.

Of course a larger hollow rod with dynamite, gunpowder, or chemical explosive could be used to create a much larger EMP but the danger of the device scales upward dramatically. This is the typical method used for EMP weapons and grenades.  Note that even a firecracker will drive the magnets out of the tube at high speed, effectively turning each magnet into a potential deadly projectile.

How to defend your electronic gear (and yourself) from an EMP attack

Are EMPs harmful?

Are EMPs really something we need to worry about? Consider these two events modern-day events.

July 9, 1962 – Starfish Prime test (Johnston Atoll)

Starfish Prime explosion photographed from HawaiiThe Starfish Prime test of a 1.4 megaton thermonuclear weapon about 250 miles above the Earth took place on July 9, 1962 on the Johnston Atoll. The pulse created by the explosion was much stronger than scientists had anticipated. As a result, streetlights in Hawaii, located more than 900 miles from the explosion, were knocked out by the electromagnetic pulse. Years later it was revealed that even non-electrical ignition systems on some cars were permanently damaged by the nuclear-generated EMP.

March 1989 Geomagnetic storm

On March 13, 1989 the Earth was hit by a massive coronal mass ejection. The event began with extremely intense auroras at the poles (could be seen as far south as Texas and Florida). As a result of the EMP, some satellites in polar orbits lost control for several hours (weather images around the world were lost during the outage). The EMP tripped circuit breakers on Hydro-Quebec’s power grid causing a massive blackout that lasted 9 hours. Scientists noted that the strength of the EMP was only 1/3 of another coronal mass ejection event recorded in 1859 (the Carrington Event).

What do EMPs damage?

Japanese infographic illustrating EMP bomb construction and operationIf visions of miles and miles of stalled cars on the highways come to mind as a result of a EMP attack, take heart. We really don’t know what an EMP will do. For instance, scientists are unsure if airplanes would fall from the sky (military jets are presumably hardened to resists EMPs).

Contrary to popular belief, the potential damage to automobiles is uncertain but likely not as serious as portrayed in the movies. In 2002, the EMP Commission conducted EMP tests on 37 cars ranging in age from 1 to 20 years old. The EMP pulses were purposely kept weak to keep from permanently damaging the cars (they were on loan to the organization and had to be returned in working order). Out of 37 cars, 3 cars stopped running (they slowly glided to a stop and could be restarted afterward) and one car suffered damaged that required repairs. 25 of the cars experienced only small malfunctions (e.g. lights flickered but the car did not stall out). 8 of the cars exhibited no problems at all.

On the other hand, since EMPs damage electronic components, many devices around the planet could be destroyed and given the importance of modern electronics in our society, the outcome could indeed be considered catastrophic.

How a device reacts to an EMP depends partly on the device’s design and partly on the type and strength of the EMP. E3 EMPs likely would not impact automobiles but could knock out power grids. But an E1 EMP can easily fry a device and even slower E3 EMPs can be purposefully concentrated to create damaging pulses. For instance, weaponized EMP devices exist that can knock out a car’s electronics causing it to stall. These devices are designed to “pull in” and focus the EMP blast through the design of the antenna (the copper coil in our homemade EMP devices). A similar effect can be inadvertently realized by metal building girders, wiring, antennas, etc.

In other words, when it comes to EMPs, the severity and resulting damage is pretty much up in the air.

Ways to protect against an electromagnetic pulse attack

Look for devices that are EMP resistant

Firstly, look for devices that are designed to guard against EMPs. Some electronic components are more sensitive to EMP than others. The most sensitive components include IC circuits and FET’s (Field Effect Transistors). Many electronic devices in use today utilize one or both of these components and some are designed to incorporate induction shielding around the electronic components. Other design factors that make a device more EMP resistant include the use of self-contained battery packs and the design of the circuit board itself (e.g. tree formation circuits are better protected than standard loop formations).

Use a surge protection device designed to guard against EMPs

Ovanic threshold devices are designed with solid state switches capable of tripping an open a path to ground when a massive EMP is detected. This can help insulate some devices from EMP damage.

Recognize devices that are naturally EMP resistant

Some devices by nature of their design are at least in part, naturally EMP resistant. These include large electric motor housings, vacuum tube equipment, electrical generators, transformer casings, microwave ovens, etc. A device susceptible to EMP damage can be placed in these enclosures to insulate against EMPs.

Use a Faraday box to protect equipment/gear against EMP damage

Metal mesh for a Faraday cage or Faraday box)What is a Faraday box (or Faraday cage)?

A Faraday box is a metal box designed to soak up EMPs.  The EMP travels around the outside metal surface of the box keeping anything inside the box protected from EMP damage. The Faraday’s box’s metal shield may be solid, mesh, or even a metal grid-like framework. The variety in surface possibilities means even an enclosure such as a metal-framed building, provided the device to be protected is not touching the structure, offers some EMP protection.

Factors that impact the effectiveness of a Faraday cage

The effectiveness of a Faraday cage is dependent upon various factors including the thickness of the metal container wall and how tight the meshing is. The effectiveness of a Faraday cage also depends on the frequency of the EMP wave (i.e. the higher the frequency of the EMP, the smaller the mesh needs to be).

Some containers exhibit intrinsic Faraday box properties including metal cake boxes, ammunition containers, metal garbage cans, and metal filing cabinets. Two metal shopping carts could be stacked on top of each other to create a Faraday cage.  Cars remain somewhat resistant to EMPs because they have many Faraday box-like properties (weak points include the glass windows, plastic grills, and fiberglass components in the body).

Making a Faraday box to protect against EMP

Constructing a Faraday box is simple. You can make one by lining a cardboard box with aluminum foil. Even a room wallpapered with copper or aluminum foil can be used as a Faraday box as long as you ensure (1) metal screens are used on any windows, (2) the door is also covered with foil, and (3) no electrical lines or cables are allowed to extend into the room.

Additional considerations

A Faraday cage demonstrationRemember the Faraday box loses its effectiveness if the object to be protected comes into contact with the Faraday box’s insulating material. To avoid this, insulate the electronic equipment with plastic, wadded paper, or cardboard.

Also note that a Faraday’s metal shield should be continuous with no large gaps (it doesn’t have to be airtight though).

Finally, an insulated, sealed carry bag acts like a Faraday box. These bags are insulated with a thin layer of aluminum foil and are designed to keep the bag’s contents cool (or hot). Due to the aluminum foil layer, they also provide a fair amount of EMP protection.

Additional information about Electromagnetic Pulses (EMPs)

EMP frequency ranges

An electromagnetic pulse can rage in frequency from DC (zero Hz) to frequencies approaching the ultraviolet and X-Ray ranges. The EMP frequency range is sometimes referred to as “DC to daylight”.

Sparks from an EMP device

An EMP device can produce an optical trail such as lightning or sparks but these are side effects of the current flow through the air and not part of the EMP itself.

Non-nuclear electromagnetic pulse (NNEMP) devices

A NNEMP is a weapon-generated electromagnetic pulse that does not use nuclear technology. They use wave-shaping circuits between the pulse source and the antenna (the copper coil in our homemade devices) to optimize the frequency of the pulse. Like the firecracker EMP device described about, NNEMPs typically use some sort of explosive as their initial energy source.  This is the most common EMP weapon design in use today.


Illustration - EMP bomb


Sources: Wikipedia, Wonder How, Wired Magazine, Stan Deyo, Future Science, Electronic Products, Extreme Tech, WND
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