7 kiloton North Korean miniature hydrogen bomb or neutron bomb test, 6 January 2016

North Korea today reportedly tested a 7 kt enhanced neutron or miniature hydrogen bomb underground, 30 miles northwest of Kilju, causing a 5.1 magnitude earthquake felt in South Korea, similar in size to its 7 kt pure fission nuclear weapon test of 12 February 2013.  We have shown previously how such enhanced neutron or neutron bomb designs maximise the prompt gamma ray emission that generates EMP when detonated at high altitude 100 km over a country (since the fusion neutrons scatter off the bomb casing to boost the prompt gamma emission).  Declassified U.S. two-point implosion patent information now openly available shows the design of such tiny, miniaturised nuclear warheads and the detailed missile warhead bus ejection patent declassification has enabled such nuclear weapons to be easily loaded on to existing North Korean missile systems:

Above: declassified EM1 Capabilities of Nuclear Weapons data on prompt gamma from different designs of nuclear weapon. Weapon type 13, the enhanced radiation weapon, is a miniature hydrogen bomb of low kiloton range yield, with approximately 50% fission and 50% fusion yield.  It enhances not only neutron output, but prompt gamma rays, which generate the strongest EMP field strength.  The 1962 Starfish Prime high altitude nuclear test of 1.4 megaton only had a 0.1% energy release in prompt gamma rays due to its thick outer casing, but the EMP from that small release of prompt gamma rays still fuzed streetlamps in Hawaii, 1300 km away from 1.4 megaton detonated at 400 km altitude.  By contrast, the low kiloton range type 13 enhanced radiation weapon, a neutron bomb (the mini H bomb North Korea tested today) releases 2.58% of its energy as prompt gamma rays, fully 25.8 times more energy per unit yield than the 1962 megaton range test!

This information suggests that the small North Korean hydrogen bomb, about 7 kt or so in size, may be a special EMP bomb.

Some of the usual mass-media dominating suspects, who scare-monger about our own weapons but pretend there's no risk of terrorism from enemies of freedom, have claimed that putting a fission bomb and a fusion fuel capsule into a shared case to make a neutron bomb is scare mongering because it's beyond the remit of Kim-Jong un's physics degree.  That kind of "logic" from famous media-loved "international security experts" (who I'm guessing don't want critical publicity) "proved" that there was no threat of Pearl Harbor on 7 December 1941 because they knew Japan wasn't advanced enough to make special torpedoes for shallow water.  Likewise, some claim that although North Korea has tested successful fission nuclear weapons and missiles, maybe Kim-Jong un can't really put the two together, them due to the missile guidance system problem. But even old declassified Polaris missile guidance system patents are adequate for EMP high altitude bursts, because even with a mile or two error in burst position, the range of EMP from a high altitude burst is not significantly affected.  The original 1960's nuclear SLBM submarine system was Polaris.  The guidance system Polaris used was declassified and published as a 55 pages long patent in 1984 (linked here), and was simply an inertial gyroscope system, an improvement to the guidance system used in the WWII V2 rocket:

Openly published Polaris SLBM nuclear missile gyroscope guidance system patent, an updated V2 type. Although the argument can be made that this was "obsolete" by Trident in 1984 when far more accurate GPS satellite guidance became available (along with terrain contour guidance for cruise missiles), it is still relevant to high altitude EMP attacks, which have such large range effects that errors of a few miles are unimportant.  The arguments about "secrecy" boil down to truth versus scare mongering.  The reality is, we don't know everything about enemies, so there's always doubt, which proved costly in the past (Hitler's secret rearmament while the left disarmed, 9/11, Pearl Harbor, Sputnik, the real 1970's missile gap when the West was stuck but Brezhnev accelerated), but Fred Kaplan and colleagues and the mainstream media like the Scientific American, Bulletin of the Atomic Scientists, BBC, Guardian paper, etc., only want to publish obsolete 1960's nuclear accident scare stories about our nuclear weapons, that we have for deterrence; it's politically taboo for them to publish today's risks from enemy threats, those who have a problem with freedom and with its preservation by deterrence.  For such freedom hating, media dominating egotists and  hypocrites, anyone who points out a possible enemy threat is "scare mongering", whereas freedom hating, discussion banning, elitist egotists who earn money from repeating the terrorism-supporting error of the media in the 1930's (by scare mongering for our disarmament to accommodate terrorist propaganda and appease nasty people) are published, respected.

The "wall of virtual silence" in journalism created by "taboo" censorship, which applies to nuclear weapons and civil defense, in the context of refugee terrorism has been analyzed by Mick Ferrari: "In truth journalism is a pretty straightforward business ... when it comes to reporting ... the who, what, where, when, why, and how of any story ... What reporting is not about is choosing which facts are reported ... the BBC ... brings shame on the profession. ... the virtual wall of silence took almost a week to collapse ... viewers were left to think German men must have gone on some beer-fuelled crime orgy. The problem of course is that the [oppressive, freedom-hating, truth detesting, pseudo-] liberal elite would rather we never found out ... For them the supposedly wonderful multi-cultural world is a nirvana ... we must tolerate and indeed welcome other cultures but they must fit in ... the politicians who got us to this point are too scared ..."  It's indeed fear that Corbyn's CND tries to use to censor out truth, and it works where the media collaborate with politics.

Declassified warhead spin ejector mechanism for missile buses may provide North Korea's nuclear warheads with a simple proof tested missile delivery mechanism.  Also, U.S. military physicist Bernard E. Drimmer (who worked in the Explosives Division in the U.S. Naval Ordnance Laboratory, and died on 3 December 2008), an expert with numerous patents for shaped explosives, anti-tank mines, etc., has an unclassified US patent number 5450794, filed on 29 November 1963 and granted on 19 September 1995, for an implosion system relevant to compact nuclear shells, although the patent makes no mention of nuclear applications, but is passed off as merely a more efficient way of detonating conventional explosions.  Notice the shaping of the "inert barriers", or steel discs, which are thicker in the middle (pointing towards the core) in Figure 3 (showing the linear implosion system).  Linear implosion of this sort was first used successfully in the first successful Lawrence Livermore National Laboratory nuclear weapon, Teapot-Tesla (7 kilotons, detonated in Nevada on 1 March 1955) soon followed by an even smaller linear implosion weapon, Teapot-Post (2 kilotons, detonated in Nevada on 9 April 1955).  Linear implosion does not produce as much implosion pressure as a spherical implosion system of the same mass, but it does have the advantages of (a) requiring only two simultaneous detonators (reducing the complexity of the weapon design and allowing a smaller capacitor bank in the firing system, the X-unit) and (b) being a compact cylinder in shape, it fits into small nuclear bombs and shells.  For low yield weapons designed for battlefield use where the yield is deliberately not-maximised in order to avoid collateral damage to civilians due to fallout, the lower fission efficiency, due to the smaller core compression in linear implosion, is simply not a problem.

The simple radiation shield under the fission (primary) stage of a neutron bomb reduces pre-ionization that produces an excessive conduction current which otherwise shorts out part of the Compton current-driven EMP (high energy prompt gamma rays are only scattered through small angles in the Compton effect).

Declassified summary history of U.S. nuclear weapon design programs (useful for assessing North Korean research).

History of U.S. SLBM (Submarine Launched Ballistic Missile) nuclear warhead delivery system design and solid missile propellant chemical development, which would provide a second-strike capability (i.e. invulnerability to a first strike while hidden at sea, and able to deter a first strike by guaranteed retaliation capability).  North Korea claimed to test an SLBM, but that may be propaganda, although they do appear to have missile capabilities, as we reported years ago:

In December 2012, North Korea successfully launched a 3-stage missile carrying a satellite, Unha-3, into orbit. Few hits on this blog from North Korea, but interest from Russia.  Judging by the size of the vast USSR civil defense system and early USSR EMP space bursts on 22 October and 1 November 1962, during the Cold War, there are no real "secrets" here for Russians to find.  They have the data already.

 

North Korean leader Kim Jong Un photographed on 29 March 2013 in front of a large map labelled “U.S. Mainland Strike Plan,” with missile trajectories plotted from North Korea to four American state targets: Hawaii (Pacific), San Diego (California), Washington D.C., and Austin (Texas). The question is, are these intended EMP target points (high altitude nuclear bursts)?

North Korea has tested nuclear weapons (0.48 kiloton on 9 Oct 2006, 2.35 kilotons on 25 May 2009, and 7.7 kilotons on 12 Feb 2013) and missiles,most recently placing a satellite in orbit on 12 Dec 2012 using a 3-stage rocket.  This indicates that North Korea could deliver nuclear warheads exceeding 7 kilotons yield to detonate 75 km over several major American cities, producing E1 (prompt gamma ray) EMP damage that could cripple the USA.  As the graphs and maps below show, even major inaccuracies in detonation location and altitude would have comparatively little effect on the devastating EMP results.

Above: E1 (prompt gamma ray) EMP field strengths for a 0.3 gauss magnetic field at the equator.  Over central USA, the EMP strengths are doubled because the magnetic field is twice as strong, about 0.6 gauss. Notice that owing to the conduction current, the EMP increases only slowly with bomb yield.  (Note also that the EMP that crippled 30 strings of streetlamps in Hawaii from the nuclear test 1,300 km away on Johnston Island on 9 July 1962 was only 5.6 kV/m in strength as Dr Longmire reveals in EMP interaction note 353, in the era before EMP-sensitive modern electronics, thus all of the damage in 1962 was caused to large relatively insensitive overload fuses, not microprocessors or computers and power supplies.)

If the North Korean bombs have a thin beryllium tamper and minimal thickness of high explosive around the core, quite a high fraction of prompt gamma rays will be released (3.5% of the energy of fission is in the form of highly penetrating ~2 MeV prompt gamma rays, many of which obviously can escape from small, low yield bombs with relatively little shielding around their core).  The distribution of the EMP over America is plotted in graphs below, taken from the recent 2010 report for the US EMP Commission, Meta-R-320:

Herman Kahn surveyed the wide spectrum of coercive uses for nuclear weapons tests - from underwater to high altitude (EMP effects) - in his 1965 book, On Escalation, pages 214-5 (linked here):

'Consider ... the use of nuclear weapons to coerce an opponent by means of a spectacular show of force. In this case, it is clear that there is an almost continuous spectrum of alternatives available. They can be ranked as follows:

'1. Testing a large weapon for purely technical reasons almost as part of a normal test programme.

'2. Testing a very large weapon, or testing on a day that has particular political significance, or both.

'3. Testing a weapon off the coast of the antagonist so that the populace can observe it.

'4. Testing a weapon high in outer space near the antagonist's airspace [EMP].

'5. Testing lower in outer space, or directly over the opponent's country [EMP].

'6. Testing so low that the shock wave is heard by everybody, and perhaps a few windows are broken.'

Preparations so far consist of research into the effects of 10 kiloton bursts:

Above: America is preparing for urban nuclear detonations due to nuclear proliferation, which itself stems from the attraction to dictatorships of exaggerated urban nuclear weapons effects hype from the cold war era.  In the Cold War, exaggerations aided nuclear deterrence of the tremendous conventional forces of the Warsaw Pact, which was relatively cheaply (compared to conscripting half the population into a conventional army).  For example, houses were built with a clear radial line-of-sight to the fireball in the unobstructed Nevada desert in 1953 Operation Upshot Knothole test Encore which proved that if we knock all the houses down in a city to prevent any shadowing effects, thermal radiation still cannot ignite a whitewashed wooden house, but will ignite one packed with inflammables at the (very dry) 19% relative humidity of that test.  The same stunt was repeated in 1955 at Operation Teapot, shot Apple 2, where again thermal, blast and nuclear radiation effects were exaggerated by failing to simulate the shadowing and shielding of a modern city.  In Hiroshima, the secret USSBS report 92 volume 2 showed that there was an enormous difference in mean areas of effectiveness for destruction of modern city buildings and the predominant wooden houses which are not found in modern city centres, which would be the targets for nuclear attack:

 

For further discussion of the North Korean nuclear attack threats, please click here.