Electromagnetic pulse (EMP)
An EMP is the result of either:

• A natural occurrence e.g. a geomagnetic storm resulting from solar activity
  
  
• A nuclear detonation (ground burst or a specific HEMP (High Altitude Electromagnetic Pulse weapon)
  
  
• A non-nuclear 'E-bomb'

Today, advances in technology now offer non-nuclear weapon powers the opportunity to deliver an electromagnetic pulse weapon. Allowing for (i) the precision targeting ability of modern weapons and (ii) the vast number of vulnerable key point installations (KPI) targets, means that the overall threat from an EMP attack has multiplied greatly.

Without taking suitable precautions there is a very high probability that such an event would interfere severely with a country's critical strategic infrastructure. This includes all forms of electronic communications (and their associated networks), navigation systems, power distribution (particularly grids), transport, utilities, data processing centres, financial markets – all essential services needed to maintain a functioning society.

All of these activities would be effectively dead or seriously incapacitated.

Weapon detonation (nuclear)

E-bomb

The physics of an EMP event is complex but the net result is a very powerful but short lived electromagnetic field radiating outwards with decreasing intensity – shock-wave, something akin to an electrical tsunami. The impact of this can be felt hundreds of kilometres away from detonation. Overall, an EMP will cause irreparable physical damage not dissimilar to that of a lightening strike.

The EMP arrives as either a single pulse or multiple pulses. Whatever the case, a high transient voltage, in the tens of thousands of volt range, will be induced. The effect of this on exposed electrical conductors is dramatic and can lead to the electrical breakdown and thermal damage to components, circuit boards as well as power devices such as electrical motors or transformers.

Sunspot activity creates intense magnetic disturbances on the surface of the sun resulting in solar flares and mass coronal ejections. These normally impact on the earth some 8 days later and on a global basis.

violent solar activity

Such events are cyclical and can vary in intensity. Whilst the Earth’s magnetic field protects us from this lethal radiation, the solar blast will generate a ‘geomagnetic storm’ – a temporary disturbance of the Earth’s magnetosphere.

solar storms and the Earth’s magnetic field

solar storms and the Earth’s magnetic field

One effect is to produce aurorae but if sufficiently intense and classified as a High Impact / Low Frequency (HILF) event, then the resulting electromagnetic pulse can impact on the key areas referred to earlier plus a large number of every-day electrical / electronic devices. The overall economic impact of such events can be considerable.

Solar storms and the Earth's magnetosphere

Lightening also produces an EMP but lightening is not static and occurs at a single point / location whereas the key problem under consideration is where the impact of an EMP if felt simultaneous over a wide area. Nevertheless lightening has been found to produce x-rays and gamma rays and this phenomenon is currently being studied.

lightening generated

• Electromagnetic Shielding
• Magnetic Field Shielding
• Helium Quench Pipe Systems
• Electromagnetic Pulse (EMP)
• Definitions

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