The Difference Between EMP and CME

(You can also listen to the podcast on EMP and EMP Protection.)

Be sure to check out the videos I did that demonstrates shielding against a 50,000 watt AM signal, and the Surviving EMP Mini-Guide:

There is a lot of misinformation about Electromagnetic Pulse (EMP) 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 an EMP attack and a CME impact is what is effected.  For EMP, 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 no like the E1 and E2 pulses.
    • It’s a very slow pulse, which can last up 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 out 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.

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8 Responses to The Difference Between EMP and CME

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  5. SpaceCat says:

    Your title is completely misleading: you never differentiated the physical difference between an EMP and CME. All your descriptions were of EMPs, which led me to believe that you really don’t know what a CME is.

    An EMP is just as its name suggests: It is a pulse driven by electromagnetic waves, which are waves that are comprised of both electrical fields and magnetic fields, oscillating at pi/2 radians (or perpendicular to) apart from each other. EMPs are electromagnetic radiation.

    A CME, however–Coronal Mass Ejection, is plasma, which is a super-heated and ionised gas that is expelled from the surface of the Sun. It’s gas that lacks the high pressure of those on Earth, but still contains the intense heat (which is unusual since higher temperatures are caused by the higher pressure of the atoms smashing together and undergoing friction, which releases thermo radiation–heat).

    And there ya go.

    • Rob Hanus says:

      I could see how it’s misleading if one didn’t have the proper perspective. This article is part of a series on EMP Preparedness. The physical differences between EMP and CME were not the focus of the article.

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  7. davecline says:

    The E3 like pulse of a CME, though, as it induces geomagnetic induction current, won’t such currents also emanate within small transformers, coils, large antennas, coiled antennas, and vast wired networks like those in all homes and office buildings? And if such currents do show up in unlikely places, not just in powergrid transformers, won’t such unlikely places spawn mini-meltdowns? Fires. Or destructive currents within their own limit environments?

    A massive solar flare with an accompanying X-30 class CME directed straight at the Earth would first cook the satellites, and induce an E1 like pulse in high altitude electronics yes? And then days later the E3 like pulse of the CME itself would wash over the earth triggering GIC type DC powersurges which would cook more than just our power grid don’t you think?

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