The Difference Between a Solar Flare and an EMP

May 6, 2015

in Negative Events

A solar flare is an ejection from the Sun of a large amount of energy. Streams of electrically charged particles (electrons and ions) are hurled out into space along with a variety of wavelengths of radiation. During active solar cycles, this can occur several times each day, but relatively few of them travel directly toward Earth. Solar flares are often followed by a Coronal Mass Ejection (CME), which is a jet of charged plasma, comprised of mostly electrons and protons. The faster radiation from these solar events can reach Earth in as little as fifteen minutes, but the slower particles often take several days to travel the same distance. Both solar flares and CMEs can cause disruptions on Earth known as “geo-magnetic storms”.

An ElectroMagnetic Pulse (EMP) is a secondary effect from a nuclear explosion. It does not come directly from the nuclear device, but is mostly an electron cascade in the atmosphere that is triggered by gamma radiation from the explosion. This cascade is maximized when a low to moderate yield fission device (<400 kilotons) is detonated well above the lower atmosphere. This allows the gamma rays to spread out over a wider area before they enter the layers of air and begin causing the electron cascade. For this reason, a device detonated several hundred kilometers above the Earth with the intention of causing a widespread EMP, is often referred to as a High Altitude EMP (HEMP). A typical EMP produces three distinct waves:

  • E1 – caused by gamma rays starting an electron cascade in the atmosphere. This wave is very fast, lasting less than one microsecond, often contains great power, and spans a wide range of frequency/wavelengths. This allows it to interact with very small conductors, inducing high voltage that is beyond the tolerance of microcircuits.
  • E2 – also caused by gamma rays, but not as fast or powerful as the first wave. This wave causes damage similar to surges from lightening storms and is normally less than one second in duration.
  • E3 – caused by a distortion of the magnetic field around Earth and has effects similar to solar flares and CMEs. This wave can last for many seconds and induces current surges in long conductors, like power lines and railroad rails.

Solar Flares/CMEs – have the ability to induce current in long lines and burn out critical components such as transformers and high voltage circuit breakers. While there is also a danger from the various forms of radiation, this is filtered by our atmosphere, protecting us at ground level, but still dangerous to satellites and other spacecraft.


  • E-1 can burn out most electronic circuits with its wide frequency range and strong power. This damage can include circuits designed to protect against normal surges because the E-1 wave is faster than their reaction time.
  • E-2 is not as fast or strong, but with no surge protection left, it may also damage any circuits that survived the first wave.
  • E-3 induces current surges in long lines and can damage transformers and high voltage circuit breakers in a manner similar to a geomagnetic storm caused by solar flares and CMEs.

Solar Flares/CMEs – the main defense against strong induced current from geomagnetic storms seems to be utilizing circuit breakers and any ability to disconnect circuits. This is mostly useful on a smaller, local level. For large infrastructure electric power grids, it may be possible to upgrade the capacity of high voltage breakers to protect the system, but even then, the primary defense would be to shut the grid down before the storm arrives. While this is possible, it entails administrative and political difficulties and also creates problems with attempting to restart a power grid from a completely “black” state. The most effective mitigation efforts may be found in facilitating the repair and recovery process after damage is absorbed. This is difficult because of the limited manufacturing and distribution of the large components involved and the cost of any duplicates.


  • E-1 damage can be prevented by Faraday shielding and natural shielding provided by bunkers and underground installations. Shielding can expensive and unwieldy, so while some critical components may be moved inside shielding designed to allow continued operation, the most effective use of shielding may be to protect spares and key equipment that will enable repair efforts.
  • E-2 surge protections against very fast spikes are not cost effective in most cases. Shut down and disconnect of circuits prior to an EMP is unlikely with no warning.
  • E-3 preventative measures are similar to those for geomagnetic storms caused by solar flares and CMEs.

Solar Flares/CMEs – while solar activity is not highly predictable in a long term sense, we do get some warning when energy and material is ejected that is headed our way. Several hours if not a day or two is a normal warning time for the arrival of the damaging parts. Considering the high frequency of flares that do not move directly at us, the eventuality of one that is coming at us is simply a matter of time. Most flares that do impact our planet are not strong enough to be dangerous but it seems likely that a flare strong enough to do significant damage will hit us eventually.

EMP – events are not predictable because the primary motivation for using this attack vector is the likelihood of a failure of attribution. Without the attribution of an attack that allows retaliation, an asymmetric strike becomes a possibility. Conventional long distance nuclear attacks by missile are easy to attribute to the launching area and usually to a specific country, thus creating strong deterrence. An HEMP attack comprised of a single low to moderate yield nuclear explosion high over the atmosphere can be delivered by a variety of means that are difficult to attribute.

EMP Disaster Timeline
Scenario: ElectroMagnetic Pulse (EMP) and Solar Flares
Faraday Protection
Making a Faraday Blanket

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