What are the frequencies that cause damage to electronics like computers? EMPs are a much lower frequency than x-rays, for example, so I’m guessing if x-rays also cause damage, they do it by a different mechanism. To my knowledge, one cannot build Faraday cages for the higher frequencies of the EM spectrum, just the lower ones (like radio waves). Phenomena like mass coronal discharge produce radiation across the spectrum - so what does this mean for building electronics? My primary question is probably about understanding the various mechanisms for malfunction in electronics.
Radio waves of all frequencies will induce currents onto wires and cause damage that way. Higher frequency electromagnetic radiation like X-rays can cause memory states to flip inside of a computer, which can cause data errors and can make the computer crash, but usually won’t do any permanent harm. Ionizing radiation can cause some harm to semiconductors, but in small amounts probably isn’t going to be noticeable.
It should be noted that damage due to electromagnetic pulse is different from simply experiencing interference or ionizing radiation. EMP basically acts by inducing resonance modes within an electrical system which causes it to accumulate static charge or current at high frequency until it reaches a breakdown limit of the semiconductor material.
A Faraday cage (an enclosed conductive cage of metal mesh) insulates against static electrical fields, but may provide only limited protection against electromagnetic radiation (depending on the completeness and fineness of the mesh) and does not insulate at all against magnetic fields. Devices within a cage may be subject to electromagnetic pulses of high frequency even if it is currently enclosed if radiation can enter through gaps such as doors jambs or cableways, and can definitely develop a pulse that enters via a conductor outside the case. It is also subject to induction within the case via a moving or changing magnetic field, which may either be generated directly by the pulse or as a response from conductors outside the case.
Most critical electronics (such as avionics in aircraft) are generally protected against the high frequency noise such as cellular signals and any interaction of other systems but this is generally done by placing adequate physical separation from the systems, providing adequate ground with isolation against back voltage, providing noise filtering capability within a digital system, and whatever minimal shielding a designer can get away with. These are intended to protect against the milliwatt-range inputs that create noise. An electromagnetic pulse, on the other hand occurs at farfield power densities the high tens of KW/m2 to MW/m2.
With the exception of electronics specifically designed to operate in a high radiation environment (such as spacecraft avionics) the noise-protection, isolation, and physical and logical hardening features of most commercial electronics simply cannot cope with the power densities developed by high energy electromagnetic pulses, and undergo dielectric breakdown well before the 50kV atmospheric saturation limit. Indeed, efforts to make commercial electronics more energy efficient have also largely made them more sensitive to external interference and pulse damage. Military avionics and hardened electronics have special design features including elaborate isolation and robustness against the damage due to EMP. In other words, they aren’t protected from experiencing the effects of the pulse so much as assuring that they don’t suffer damage from induced currents and high voltage breakdown.
Stranger