The Difference Between Solar Flares and Nuclear EMPs: An Expert's Perspective

Electromagnetic pulses (EMP) are powerful bursts of energy that can cause significant damage to electronic equipment. They can be caused by both solar flares and nuclear explosions, but there are some key differences between the two.

Solar flares

, also known as coronal mass ejections (CME) or geomagnetic storms, vary widely in intensity and can last much longer than nuclear EMPs. A nuclear EMP is more energetic and has a shorter burst. Smaller EMPs can cause power grid blackouts, while larger ones could potentially destroy part or all of the power grid.

According to testimony before a congressional committee, a prolonged collapse of the power grid due to hunger, disease, and social collapse could result in the death of up to 90% of the American population. Serious storms, such as the Carrington event of 1859, are expected to occur approximately once every 150 years. High-voltage transformers are the weak link in the system, and the Federal Energy Regulatory Commission (FERC) has identified 30 of them as critical. The simultaneous loss of just 9, in various combinations, could paralyze the network and cause a cascading failure, leading to a “coast to coast blackout”. If HV transformers are irreparably damaged, they may not be replaced for 1 to 2 years from now, which would be devastating. To answer these questions, I did some homework.

I read congressional testimonies, technical reports from expert groups, a book, academic articles, insurance company evaluations, several industry technical reports, and several reports in the specialized media. What I found was sometimes contradictory. Somewhat worryingly, both sides of the issue accused each other of bias due to financial incentives. Overall, my view is that while some of the risk of EMP and solar storms is overrated, it is still a serious problem and one of the main secondary risks for which we should prepare. The combination of human intervention and automatic network self-protection makes me feel that long-term catastrophic collapse caused by a solar storm is unlikely but possible. In their voltage injection tests, experts discovered that with sufficient tension, the inputs of the DPRs could be permanently damaged.

Some devices required voltages of up to 80 kV to be damaged while others required voltages as low as 5 kV. But what's even more interesting is that the induced voltage also depends on the polarization of the field, the angle of incidence (psi), and the azimuthal angle (phi). Depending on where the input power line is located and how it is oriented, the actual induced voltage can be much lower than what you would expect under peak conditions. Based on the known locations of the substations in the U. S., experts were able to estimate the distribution of the voltages induced in these substations assuming a very strong nuclear attack.

In most cases, the induced voltages would be lower than 10 kV but some would be even higher. A malfunction of the relays during a HEMP attack would likely result in the failure of other power grid systems leading to large-scale cascading blackouts and widespread equipment damage.


s are by no means one of the main national security challenges nor the most pressing concern for the security of our electrical grid. A careful and reasoned plan presented like the one we saw last week at the White House makes sense. Other people especially those who have worked on the EMP Commission are much more concerned about these risks. They point to the fact that hundreds of network components have not been thoroughly tested and that problems in one part of the network can cascade to other parts in an unpredictable way. Sometimes, media have portrayed these people in a negative way.

In an article that seemed irresponsible to me Slate described EMP's concern as “a right-wing concern and a conservative fixation” while Wired says that EMPs field is full of “exaggerations” and “alarmism”.The effects of E2 induction look similar to and are equivalent to electromagnetic pulse radiated by a beam that hits during a shock on electronic devices and sensitive equipment. Electromagnetic pulses (EMP) from nuclear weapon detonations at altitudes of 30 to 400 kilometers (18 to 50 miles) can damage or destroy sensitive electronic equipment at ground level.

Preston Mcnealy
Preston Mcnealy

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