Monday, October 22, 2012

The Difference Between EMP and CME

CME = Coronal Mass Ejection = Solar Flare
HEMP = High-Altitude ElectroMagnetic Pulse = Nuclear Bomb

There is a lot of misinformation about High-Altitude Electromagnetic Pulse (HEMP) and Coronal Mass Ejection (CME) events, about what they are and how they effect things.  One of the big misconceptions is that they are the same.  While they may have a similar component and both can cause power outages, there are some striking differences.
The main difference between a HEMP attack and a CME impact is what is effected.  For HEMP, both the power grid and electronics are damaged and destroyed.  In a CME impact, mainly the power grid is affected, while electronics are untouched.
There are actually three components, or pulses, to an EMP, they are called E1, E2 and E3:
  • E1- The first component is a very fast, high voltage pulse. It is very brief, but very intense.
    • It is much faster than lightning and common lightning and surge suppressors will not stop this pulse.
    • It induces high voltages in wiring and cables, like power lines, phone lines, etc.
    • This is the component that destroys computers and electronic equipment.
  • The E2 pulse is a lot like lightning and is easier to protect against, though if the protection circuit was destroyed or damaged by the E1 pulse, may still do more damage.
  • The E3 pulse is a long duration pulse and is not like the E1 and E2 pulses.
    • It’s a very slow pulse, which can last for minutes.
    • It is caused by the nuclear detonation disrupting the Earth’s magnetic field. Which sounds a lot like what happens during a CME impact.
    • This is the wave that shuts down the power grid. It does this by inducing a DC-like current. When enough DC current flows through a transformer, it melts.
While a CME can damage electronics in space, such as those on satellites and on the Space Station, it doesn’t generate any E1 pulse.  A severe CME could take out large portions of the power grid for years, but they would not damage any electronics equipment down here on Earth unless, perhaps, connected to the power grid or other very long lines.