A bolt of lightning makes about as much as EMP as what leaks out of a microwave oven. The EMP from the USSR’s 1961 Tsar Bomba blast bent the magnetic field OF THE ENTIRE PLANET. The comparison is absurd.
Damage from EMP is mostly confined to the blast area. That’s because EMP from an atomic blast is the result of gamma rays emitted by the fission process (or fusion, depending). And gamma rays diffuse pretty rapidly in an atmosphere as dense as ours.
Plus, there’s the inverse square law, which governs the propagation of all electro-magnetic energy, including gamma rays. EMP strength diminishes at the inverse of the square of the change in distance, so an object that’s twice as far away will receive only one-fourth as much energy:
( 1x * 1/(2^2) = 0.25x ).
Three times as far away receives only one-ninth as much EMP:
( 1x * 1/(3^2) = 0.11x ).
The gamma radiation (and hence the EMP) will diminish at the sum of the two, the atmospheric diffusion and the inverse square law. Plus, EMP is not a “homogeneous” effect. Its distribution naturally tends to the erratic.
So if your barn survives the nuclear blast, the vehicles inside it also stand a fair chance of remaining operational. Not because the barn protected them from the EMP but because the barn’s survival is an indication of its distance from the blast.
All of the city of Hiroshima’s electrical power plants were on the perimeter of the city. Ground Zero was at city center. All the damage sustained by the power plants was blast damage, and very little of that. After the bomb, power production continued pretty much normally. But those facilities would have had far less solid state equipment than today. And it’s difficult to assess how much EMP damage there was nearer to Ground Zero because thermal and blast damage obliterated much of the evidence.
And just because an electronic device isn’t plugged in at the moment of the blast won’t necessarily protect it from EMP. An electric generator produces current by moving a magnetic field in relation to a conductive material (or vice-versa). In the same way, EMP also causes a warping of the earth’s magnetic field which can induce an electric current whenever it strikes a conductive material. Anything with a solid state component, an integrated circuit or a silicon chip could be vulnerable. They started putting capacitors in cars in about 1910, so I have no doubt but that a 1987 Toyota would be vulnerable ...presuming it’s close enough to the blast, and that it’s OE Faraday cage doesn’t protect it.
The effect will be magnified as it travels across the power grid or down an antenna but it doesn’t much matter whether a solid state device is plugged in or turned on because EMP brings its own electricity to the party.
Automobiles in general should fare pretty well because they carry their own Faraday cage around with them. So after they drop the big one, it would suck to own a Corvette. Anything built before they introduced capacitor discharge ignition (CDI) just won’t give a hoot.
History often leaves out the fact that the Enola Gay and Bockscar were accompanied by a number of support aircraft on their atomic bombing missions, including one carrying a camera crew, another carrying scientific instrumentation and several weather observation planes. Several of them flew on both missions, including the Enola Gay, which served as a weather observation plane on the Nagasaki mission. So it’s pretty clear that none of these airplanes were disabled by their exposure to the atomic blast(s). Which is a pretty good advertisement for the magneto ignition system, if you’re a Prepper. Then again, the bombers themselves were closest to the explosions, and they both would have been almost seven miles away at the instant of detonation.
So the best strategy is to be elsewhere when the bomb goes off.
“A bolt of lightning makes about as much as EMP as what leaks out of a microwave oven”
No sir.
“Damage from EMP is mostly confined to the blast area. “
No sir.
“Plus, there’s the inverse square law, which governs the propagation of all electro-magnetic energy”
Yes, but not in the “near field” - (I can explain this if you want) - in the near field - 1/r, not 1/r^2 is operative.
” Plus, EMP is not a “homogeneous” effect. Its distribution naturally tends to the erratic.”
No sir.
” barn’s survival is an indication of its distance from the blast.”
No sir.....incidentally, from a high altitude nuclear blast (>30km in altitude) there will be no significant blast effects on the ground.
“And just because an electronic device isn’t plugged in at the moment of the blast won’t necessarily protect it from EMP”
Yes!
“EMP also causes a warping of the earth’s magnetic field”
You’re confusing the “E3” effect from the “E1” effect of an EMP. This thread refers to the “E1” aspects for the most part.
Overall on this post you seem to be confusing a “Source Region” EMP (one that is near a ground or close-to-ground burst with a High-Altitude EMP.)
“So the best strategy is to be elsewhere when the bomb goes off.”
Hard to argue with this point!