First of all, there are a number of prior threads discussing the topic of high altitute electromagnetic pulse (HEMP) attacks, including one from last year specifically addressing North Korean capabilities:
[POST=20392581]So can the mad Korean bring us to our knees with EMP?[/POST]
[POST=18994114]EMP vs. Nuke?[/POST]
[POST=14005803]EMP effects[/POST]
[POST=15955896]North Korea and E.M.P.[/POST]
[POST=11780688]How much EMP shielding does military equipment has?[/POST]
[POST=13966680]Solar flares, EMP, and electronics damage[/POST]
[POST=17910477]How to protect solar panels from a Carrington event (EMP)?[/POST]
It should be noted that most of what we know about the HEMP effects of an actual nuclear detonation come from the Hardtack I series Yucca, Teak, and Orange and Starfish Prime tests performed in the late 'Fifties to early 'Sixties. There has been other work to model atmospheric effects and some very expensive component and system testing of simulated HEMP effects up to the 50 kV/m atmospheric breakdown limit but everything we know about the scope and effects of an HEMP attack at a given altitude over a given region is speculative.
To address a few specific comments:
This is something of a pet peeve of mine, but while it is a common use of the term by the general public to address any nuclear deterrence or exchange as “MAD”, this is completely incorrect. Assured Destruction (the “Mad” was added later as sardonic commentary by Herman Kahn and other critics of deterrence theory in general) is a specific game theory application of deterrence between and only two parties that requires specific prerequisites, including parity, survivability/counterstrike capability, and overwhelming destructiveness of the parties’ respective nuclear arsenals. The premise of Assured Destruction is that it is by definition a game with no possibility of winning (hence ‘destruction’ is ‘assured’) and therefore no rational player will initiate attack knowing that it would mean certain destruction of their nation and society. Any action that results in an exchange is a failure of the premise of Assured Destruction.
This absolutely does not apply to the situation between North Korea and the United States, where North Korea has a very limited ability to attack the United States (at most being able to destroy a handful of cities potentially an HEMP attack) notwithstanding the anti-ballistic missile systems which are at least ostensibly capable of fielding against such a limited attack with good efficacy, while the United States could most certainly destroy North Korea and virtually everyone with its borders if it so chooses with plenty of retaliatory capability remaining.
The Carrington Event of 1859, referenced in the last two links above, was the result of a coronal mass ejection (a large eruption of charged particles from the Sun), which in certain respects produces similar effects of the E3 component of EMP but its not representative of the effects of EMP on hardware components. Its greatest effects would be on the power grid which is detailed in this JASON report: “Impacts of Severe Space Weather on the Electric Grid”, JSR-11-320, November 2011. It does not present the same conditions that generate the E1 and E2 (high and mid frequency) components of HEMP.
A car body is most certainly not a Faraday cage, which is readily demonstrated by watching the many drivers operating their cell phones within one. A vehicle will often conduct lightning through the body panels and away from the delicate components and occupants in the interior by what is known as the ‘skin effect’, but this is not the same effect as that produced by a Faraday cage, which relies upon the even distribution of an essentially static electrical charge around a conductive mesh or solid shell. Even if components are within a shield of some kind that acts like a Faraday cage it may not do much to protect it from highly transient magnetic pulses generating high induction, nor will it do anything to protect a component that has a conductive path to the outside world, such as a radio attached to an antenna. It is, in theory, possible to provide isolation protection against high frequency pulses through such a conduit but it is very expensive to design and test such a system and may have other undesirable effects such as interference or poor signal efficiency.
With regard to the short and long term effects of such an attack and the range over which the effect could occur, it really depends on the specifics of the weapon and the amount of yield of energetic X-rays it produces at a certain altitude. The intensity and especially the range over which the effect occurs is highly dependent up being at an optimal altitude where the X-rays will be widely distributed before being absorbed.
The HEMP E1 component effect is the result of interactions between those X-rays and essentially free atoms in the thermosphere which are acted upon by the Earth’s magnetic field producing synchrotron radiation, generating a semi-coherent pulse in response; very simply, it is essentially turning the upper atmosphere of the Earth into a very large maser. There is very little that can be done to protect equipment from the E1 component except by attenuating the field (with a lot of mass opaque to microwave frequencies) and making the equipment robust enough to withstand dielectric breakdown, which is essentially impossible in modern high efficiency VLSI systems. The E1 component could affect an area as large as all of the US Eastern Seaboard all the way to Ohio and Kentucky, or the entire Midwest, Pacific Northwest, or Southwest regions. The shape of the affected area depends on the magnetic field flux where the weapon is detonated but it is not symmetric.
BTW, it does not matter whether components are in operation or not; the effect produces a highly transient electric charge and dielectric breakdown that will occur whether the device is functioning or not. Nor does it just affect devices with microelectronics and computers; anything with a sensitive electronic connection, including electronic car ignitions and fuel injection systems are likely to be damaged, nor is it possible to just retrofit a carburetor and mechanically-timed ignition onto a modern car, notwithstanding all of the other systems that use fine electronics or require digital control. An intense E1 component would render most modern vehicles worthless.
The E2 component is somewhat more localized and the effects are more akin to terrestrial lightning, producing a lower frequency pulse. Since most large or valuable electronic systems are designed for protection against lightning they should be fairly resistant to the E2 component, and except for a temporary disruption in radio communication it is not a great concerns.
The E3 component, a low frequency pulse, is the greatest concern for the electrical power distribution grid, and while you might hope that the companies which own the various segments of the North American grid would be prepared for an attack, particularly since it could experience the same conditions from natural phenomena, the JASON report cited above came to some pretty disturbing conclusions about the inadequacy of utilities and the government to deal with a widespread disruption of the power grid and attempts to repair it. The report is now several years old (issued in 2011) but I have seen nothing which indicates that the specific concerns listed in the report have been addressed in any comprehensive way.
As for FEMA and other government response, I think we’ve had ample demonstration of how inadequate it has been even with fairly localized disasters in New Orleans, Texas, Florida, and especially Puerto Rico. A regional or nationwide disaster would certainly overwhelm the very limited planning and further aggravate the logistical problems evident in prior disaster response efforts. Fortunately, we’ve also seen that while a limited amount of looting and thievery accompanies natural disasters, we also see people stepping up to volunteer to aid and protect others. A large scale disaster wouldn’t just turn into a Mad Max type of scenario unless there were some other looming failure in the offing.
The results on the nation that launched such an attack (and as others have noted, it would be nearly impossible to do this anonymously) would likely be very bad for them. Although North Korea has been very provocative in their statements and testing, the end goal of their nuclear weapon program is survival and to get a seat at the adults table, not to launch a desperate suicidal attack upon the US unless they are backed into a corner and feel that their existence is forfeit regardless. A ‘sneak attack’ with a high altitude EMP weapon seems unlikely in any plausible scenario.
Stranger
