HARDTACK-Teak was an exoatmospheric high altitude nuclear weapon test performed during Operation Newsreel . It was launched from Johnston Atoll on a Redstone missile . On 1 August 1958, the 3.88 Mt (16.2 PJ) shot detonated at an altitude of 76.8 km (252,000 ft; 47.7 mi).
62-431: Along with HARDTACK-Orange it was one of the two largest high-altitude nuclear explosions . The 3.8- megaton detonation was planned to occur at an altitude of 76,000 m (250,000 ft) above a point approximately 9.7 km (6 mi) south of Johnston Island. However, due to a programming failure, it burst directly above the island at the desired altitude, making the island the effective ground zero . This brought
124-543: A current density of tens of amperes per square metre. Because of the downward tilt of the Earth's magnetic field at high latitudes , the area of peak field strength is a U-shaped region to the equatorial side of the detonation. As shown in the diagram, for nuclear detonations in the Northern Hemisphere , this U-shaped region is south of the detonation point. Near the equator , where the Earth's magnetic field
186-571: A geomagnetic storm . Like a geomagnetic storm, E3 can produce geomagnetically induced currents in long electrical conductors, damaging components such as power line transformers . Because of the similarity between solar-induced geomagnetic storms and nuclear E3, it has become common to refer to solar-induced geomagnetic storms as "Solar EMP". "Solar EMP" does not include E1 or E2 components. Factors that control weapon effectiveness include altitude, yield , construction details, target distance, intervening geographical features, and local strength of
248-625: A fire that burned down the Karaganda power plant, and shut down 1,000 kilometres (620 mi) of shallow-buried power cables between Tselinograd and Alma-Ata . US Government Films: Nuclear electromagnetic pulse A nuclear electromagnetic pulse ( nuclear EMP or NEMP ) is a burst of electromagnetic radiation created by a nuclear explosion . The resulting rapidly varying electric and magnetic fields may couple with electrical and electronic systems to produce damaging current and voltage surges . The specific characteristics of
310-487: A fission explosion is 3.5% of the yield, but in a 10 kt (42 TJ) detonation the triggering explosive around the bomb core absorbs about 85% of the prompt gamma rays, so the output is only about 0.5% of the yield. In the thermonuclear Starfish Prime the fission yield was less than 100% and the thicker outer casing absorbed about 95% of the prompt gamma rays from the pusher around the fusion stage. Thermonuclear weapons are also less efficient at producing EMP because
372-463: A form of saber rattling. The worst effects of a Soviet high-altitude test occurred on 22 October 1962, in the Soviet Project K nuclear tests (ABM System A proof tests) when a 300 kt missile-warhead detonated near Dzhezkazgan at 290-kilometre (180 mi) altitude. The EMP fused 570 kilometres (350 mi) of overhead telephone line with a measured current of 2,500 A , started
434-467: A high-altitude electromagnetic pulse (HEMP) device. Effects of a HEMP device depend on factors including the altitude of the detonation, energy yield , gamma ray output, interactions with the Earth's magnetic field and electromagnetic shielding of targets. The fact that an electromagnetic pulse is produced by a nuclear explosion was known in the earliest days of nuclear weapons testing. The magnitude of
496-418: A large, radial pulse of electric current propagating outward from the burst location confined to the source region (the region over which the gamma photons are attenuated). The Earth's magnetic field exerts a force on the electron flow at a right angle to both the field and the particles' original vector, which deflects the electrons and leads to synchrotron radiation . Because the outward traveling gamma pulse
558-524: A location where the Earth's magnetic field was greater. The damage caused by the resulting EMP was reportedly much greater than in Starfish Prime. The geomagnetic storm –like E3 pulse from Test 184 induced a current surge in a long underground power line that caused a fire in the power plant in the city of Karaganda . After the dissolution of the Soviet Union , the level of this damage
620-403: A particular nuclear EMP event vary according to a number of factors, the most important of which is the altitude of the detonation. The term "electromagnetic pulse" generally excludes optical (infrared, visible, ultraviolet) and ionizing (such as X-ray and gamma radiation) ranges. In military terminology, a nuclear warhead detonated tens to hundreds of miles above the Earth's surface is known as
682-568: A short circuit on the line and some lines detaching from the poles and falling to the ground". Nuclear EMP is a complex multi-pulse, usually described in terms of three components, as defined by the International Electrotechnical Commission (IEC). The three components of nuclear EMP, as defined by the IEC, are called "E1", "E2", and "E3". The three categories of high-altitude EMP are divided according to
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#1732772898408744-480: A spherical 'cloud' until distorted by Earth's magnetic field . The charged particles resulting from the blast are accelerated along the Earth's magnetic field lines to create an auroral display at the conjugate point , which has led documentary maker Peter Kuran to characterize these detonations as 'the rainbow bombs'. The visual effects of a high-altitude or space-based explosion may last longer than atmospheric tests, sometimes in excess of 30 minutes. Heat from
806-401: A surface burst, absorption of gamma rays by air would limit the range of gamma-ray deposition to approximately 16 kilometres (10 mi), while for a burst in the lower-density air at high altitudes, the range of deposition would be far greater. Typical nuclear weapon yields used during Cold War planning for EMP attacks were in the range of 1 to 10 Mt (4.2 to 41.8 PJ ). This
868-421: A typical case of E1 pulse produced by a second-generation nuclear weapon such as those of Operation Fishbowl . The typical gamma rays given off by the weapon have an energy of about 2 MeV ( mega electron-volts). The gamma rays transfer about half of their energy to the ejected free electrons, giving an energy of about 1 MeV. In a vacuum and absent a magnetic field, the electrons would travel with
930-729: Is a very long-duration "late time" pulse, which is extremely slow in rise and fall times compared to the other components of EMP. E3 is further divided into E3A (blast wave) and E3B (heave). E3 is also called magnetohydrodynamic EMP. The E1 pulse is a very fast component of nuclear EMP. E1 is a brief but intense electromagnetic field that induces high voltages in electrical conductors. E1 causes most of its damage by causing electrical breakdown voltages to be exceeded. E1 can destroy computers and communications equipment and it changes too quickly (nanoseconds) for ordinary surge protectors to provide effective protection from it. Fast-acting surge protectors (such as those using TVS diodes ) will block
992-454: Is more closely proportional to the total energy yield of the weapon. In nuclear EMP all of the components of the electromagnetic pulse are generated outside of the weapon. For high-altitude nuclear explosions , much of the EMP is generated far from the detonation (where the gamma radiation from the explosion hits the upper atmosphere). This electric field from the EMP is remarkably uniform over
1054-484: Is more nearly horizontal, the E1 field strength is more nearly symmetrical around the burst location. At geomagnetic field strengths typical of the mid-latitudes, these initial electrons spiral around the magnetic field lines with a typical radius of about 85 metres (280 ft). These initial electrons are stopped by collisions with air molecules at an average distance of about 170 metres (560 ft). This means that most of
1116-549: Is propagating at the speed of light, the synchrotron radiation of the Compton electrons adds coherently , leading to a radiated electromagnetic signal. This interaction produces a large, brief, pulse. Several physicists worked on the problem of identifying the mechanism of the HEMP E1 pulse. The mechanism was finally identified by Conrad Longmire of Los Alamos National Laboratory in 1963. Longmire gives numerical values for
1178-493: Is roughly 50 to 500 times the size of the Hiroshima and Nagasaki bombs. Physicists have testified at United States Congressional hearings that weapons with yields of 10 kt (42 TJ) or less can produce a large EMP. The EMP at a fixed distance from an explosion increases at most as the square root of the yield (see the illustration to the right). This means that although a 10 kt (42 TJ) weapon has only 0.7% of
1240-752: The Bluegill Triple Prime shot, at an altitude of 50 kilometers (31 miles), was felt by personnel on the ground at Johnston Atoll , and this test caused retina burns to two personnel at ground zero who were not wearing their safety goggles. The Soviets detonated four high-altitude tests in 1961 and three in 1962. During the Cuban Missile Crisis in October 1962, both the US and the USSR detonated several high-altitude nuclear explosions as
1302-651: The Apia Observatory at Samoa was four times more powerful than any created by solar storms , while in July 1962 the Starfish Prime test damaged electronics in Honolulu and New Zealand (approximately 1,300 kilometres (810 mi) away), fused 300 street lights on Oahu (Hawaii), set off about 100 burglar alarms , and caused the failure of a microwave repeating station on Kauai , which cut off
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#17327728984081364-498: The Pacific basin . This was due to the injection of a large quantity of fission debris into the ionosphere . The debris prevented normal ionospheric reflection of high-frequency (HF) radio waves back towards Earth , which disrupted most long-distance HF radio communications . The nuclear detonation occurred at 10:50 UTC on 1 August 1958 (which was 11:50 p.m., Johnston Island local time, on 31 July 1958). According to
1426-546: The Starfish Prime nuclear test, most damage was to the satellites' solar panels while passing through radiation belts created by the explosion. For detonations within the atmosphere, the situation is more complex. Within the range of gamma ray deposition, simple laws no longer hold as the air is ionized and there are other EMP effects, such as a radial electric field due to the separation of Compton electrons from air molecules, together with other complex phenomena. For
1488-701: The United States Government . High-altitude nuclear explosion High-altitude nuclear explosions are the result of nuclear weapons testing within the upper layers of the Earth's atmosphere and in outer space . Several such tests were performed at high altitudes by the United States and the Soviet Union between 1958 and 1962. The Partial Test Ban Treaty was passed in October 1963, ending atmospheric and exoatmospheric nuclear tests. The Outer Space Treaty of 1967 banned
1550-461: The 22 October (K-3) nuclear test (also known as Test 184) blew all of the fuses and destroyed all of the overvoltage protectors in all of the sub-lines. Published reports, including a 1998 IEEE article, have stated that there were significant problems with ceramic insulators on overhead electrical power lines during the tests. A 2010 technical report written for Oak Ridge National Laboratory stated that "Power line insulators were damaged, resulting in
1612-434: The 50,000 volts per metre limit by unspecified mechanisms. The reality and possible construction details of these weapons are classified and are, therefore, unconfirmed in the open scientific literature The E2 component is generated by scattered gamma rays and inelastic gammas produced by neutrons . This E2 component is an "intermediate time" pulse that, by IEC definition, lasts from about one microsecond to one second after
1674-478: The E1 pulse. E1 is produced when gamma radiation from the nuclear detonation ionizes (strips electrons from) atoms in the upper atmosphere. This is known as the Compton effect and the resulting current is called the "Compton current". The electrons travel in a generally downward direction at relativistic speeds (more than 90 percent of the speed of light). In the absence of a magnetic field, this would produce
1736-447: The EMP and the significance of its effects were not immediately realized. During the first United States nuclear test on 16 July 1945, electronic equipment was shielded because Enrico Fermi expected the electromagnetic pulse. The official technical history for that first nuclear test states, "All signal lines were completely shielded, in many cases doubly shielded. In spite of this many records were lost because of spurious pickup at
1798-466: The Earth's magnetic field lines. The resulting transient electric fields and currents generate electromagnetic emissions in the radio frequency range of 15 MHz to 250 MHz . This high-altitude EMP occurs between 30 and 50 kilometers (19 and 31 miles) above the Earth's surface. The potential as an anti-satellite weapon became apparent in August 1958 during Hardtack Teak . The EMP observed at
1860-694: The Earth's magnetic field. According to an internet primer published by the Federation of American Scientists : Thus, for equipment to be affected, the weapon needs to be above the visual horizon . The altitude indicated above is greater than that of the International Space Station and many low Earth orbit satellites. Large weapons could have a dramatic impact on satellite operations and communications such as occurred during Operation Fishbowl. The damaging effects on orbiting satellites are usually due to factors other than EMP. In
1922-400: The K Project tests, Soviet scientists instrumented a 570-kilometer (350 mi) section of telephone line in the area that they expected to be affected by the pulse. The monitored telephone line was divided into sub-lines of 40 to 80 kilometres (25 to 50 mi) in length, separated by repeaters . Each sub-line was protected by fuses and by gas-filled overvoltage protectors. The EMP from
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1984-416: The ability to impair or destroy many protective and control features. The energy associated with the second component thus may be allowed to pass into and damage systems." The E3 component is different from E1 and E2. E3 is a much slower pulse, lasting tens to hundreds of seconds. It is caused by the nuclear detonation's temporary distortion of the Earth's magnetic field. The E3 component has similarities to
2046-413: The accelerating reliance on EMP-sensitive microelectronics, heightened awareness that EMP could be a significant problem. In 1962, the Soviet Union performed three EMP-producing nuclear tests in space over Kazakhstan, the last in the " Soviet Project K nuclear tests ". Although these weapons were much smaller (300 kiloton ) than the Starfish Prime test, they were over a populated, large landmass and at
2108-539: The book Defense's Nuclear Agency 1947–1997 , when the Teak detonation occurred: According to page 269 of the Defense Nuclear Agency report on Operation Hardtack: According to civilian observer reports contained in the official United States Defense Nuclear Agency report on Operation Hardtack I: [REDACTED] This article incorporates public domain material from websites or documents of
2170-444: The close-in hazards of missile launch in a confined area and the firing of missiles over water areas used for ship anchorage. That the hazard of primary concern is flashblindness and/or retinal burn expected to result from the programmed detonation. This hazard is calculated to extend to a range of 435 statute miles [700 km] at the surface... When the warhead burst at 76.8 km (252,000 ft) directly above Johnston Island,
2232-471: The devices that would normally protect against E2. The EMP Commission Executive Report of 2004 states, "In general, it would not be an issue for critical infrastructure systems since they have existing protective measures for defense against occasional lightning strikes. The most significant risk is synergistic because the E2 component follows a small fraction of a second after the first component's insult, which has
2294-510: The early days of EMP research, that the problem might not be significant. Later calculations showed that if the Starfish Prime warhead had been detonated over the northern continental United States, the magnitude of the EMP would have been much larger (22 to 30 kV/m) because of the greater strength of the Earth's magnetic field over the United States, as well as its different orientation at high latitudes. These calculations, combined with
2356-466: The electric field measurements from the 1.7 kiloton weapon exceeded the range to which the test instruments were adjusted and was estimated to be about five times the limits to which the oscilloscopes were set. The Yucca EMP was initially positive-going, whereas low-altitude bursts were negative-going pulses. Also, the polarization of the Yucca EMP signal was horizontal, whereas low-altitude nuclear EMP
2418-542: The electrons are stopped by collisions with air molecules before completing a full spiral around the field lines. This interaction of the negatively charged electrons with the magnetic field radiates a pulse of electromagnetic energy. The pulse typically rises to its peak value in some five nanoseconds. Its magnitude typically decays by half within 200 nanoseconds. (By the IEC definition, this E1 pulse ends 1000 nanoseconds after it begins.) This process occurs simultaneously on about 10 electrons. The simultaneous action of
2480-565: The electrons causes the resulting pulse from each electron to radiate coherently, adding to produce a single large-amplitude, short-duration, radiated pulse. Secondary collisions cause subsequent electrons to lose energy before they reach ground level. The electrons generated by these subsequent collisions have so little energy that they do not contribute significantly to the E1 pulse. These 2 MeV gamma rays typically produce an E1 pulse near ground level at moderately high latitudes that peaks at about 50,000 volts per metre. The ionization process in
2542-497: The energy release of the 1.44 Mt (6.0 PJ) Starfish Prime test, the EMP will be at least 8% as powerful. Since the E1 component of nuclear EMP depends on the prompt gamma-ray output, which was only 0.1% of yield in Starfish Prime but can be 0.5% of yield in low-yield pure nuclear fission weapons, a 10 kt (42 TJ) bomb can easily be 5 * 8% = 40% as powerful as the 1.44 Mt (6.0 PJ) Starfish Prime at producing EMP. The total prompt gamma-ray energy in
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2604-519: The explosion 610 m (2,000 ft) nearer the launch site control and analysis crews than intended. The Teak test was originally planned to be launched from Bikini Atoll , but Lewis Strauss , chairman of the United States Atomic Energy Commission opposed the test because of fears that the flash from the nighttime detonation might blind Islanders who were living on nearby atolls. He finally agreed to approve
2666-499: The explosion. E2 has many similarities to lightning , although lightning-induced E2 may be considerably larger than a nuclear E2. Because of the similarities and the widespread use of lightning protection technology, E2 is generally considered to be the easiest to protect against. According to the United States EMP Commission, the main problem with E2 is that it immediately follows E1, which may have damaged
2728-481: The field strength may be expected to be tens of kilovolts per metre over most of the area receiving the EMP radiation." The text also states that, "... over most of the area affected by the EMP the electric field strength on the ground would exceed 0.5 E max . For yields of less than a few hundred kilotons, this would not necessarily be true because the field strength at the Earth's tangent could be substantially less than 0.5 E max ." ( E max refers to
2790-469: The first few tenths of nanoseconds, about a tenth of a percent of the weapon yield appears as powerful gamma rays with energies of one to three mega-electron volts ( MeV , a unit of energy). The gamma rays penetrate the atmosphere and collide with air molecules, depositing their energy to produce huge quantities of positive ions and recoil electrons (also known as Compton electrons ). These MeV-energy Compton electrons then accelerate and spiral along
2852-409: The first stage can pre-ionize the air which becomes conductive and hence rapidly shorts out the Compton currents generated by the fusion stage. Hence, small pure fission weapons with thin cases are far more efficient at causing EMP than most megaton bombs. This analysis, however, only applies to the fast E1 and E2 components of nuclear EMP. The geomagnetic storm -like E3 component of nuclear EMP
2914-404: The flash effectively turned night into day, as shown in the "After" photo in the section above. The initial glow faded over a period of about 30 seconds. The thermal radiation output of the explosion was such that observers were forced to take cover in the "shade" for the first few moments, as can be seen in film footage of the test. Teak caused communications impairment over a widespread area in
2976-482: The high-altitude EMP phenomenon. The Bluegill Triple Prime and Kingfish high-altitude nuclear tests of October and November 1962 in Operation Fishbowl provided data that was clear enough to enable physicists to accurately identify the physical mechanisms behind the electromagnetic pulses. The EMP damage of the Starfish Prime test was quickly repaired due, in part, to the fact that the EMP over Hawaii
3038-595: The high-altitude test on the condition that the launch point be moved from Bikini Atoll to the more remote site at Johnston Island . According to the United States Defense Nuclear Agency report (DNA6038F) on Operation Hardtack I: Johnston Island was well situated for the high-altitude tests because of its isolation, the nearest inhabited island being 866 kilometres (538 mi) away. On the other hand, operations there had to consider aircraft and ship routes from Hawaii to Asia, as well as
3100-417: The large area affected. According to the standard reference text on nuclear weapons effects published by the U.S. Department of Defense, "The peak electric field (and its amplitude) at the Earth's surface from a high-altitude burst will depend upon the explosion yield, the height of the burst, the location of the observer, and the orientation with respect to the geomagnetic field . As a general rule, however,
3162-481: The mid- stratosphere causes this region to become an electrical conductor, a process that blocks the production of further electromagnetic signals and causes the field strength to saturate at about 50,000 volts per metre. The strength of the E1 pulse depends upon the number and intensity of the gamma rays and upon the rapidity of the gamma-ray burst. Strength is also somewhat dependent upon altitude. There are reports of "super-EMP" nuclear weapons that are able to exceed
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#17327728984083224-458: The public by causing electrical damage in Hawaii , about 1,445 kilometres (898 mi) away from the detonation point, disabling approximately 300 streetlights, triggering numerous burglar alarms and damaging a microwave link. Starfish Prime was the first success in the series of United States high-altitude nuclear tests in 1962 known as Operation Fishbowl . Subsequent tests gathered more data on
3286-553: The significance of the EMP problem after a three-article series on nuclear EMP was published in 1981 by William J. Broad in Science . In July 1962, the US carried out the Starfish Prime test, exploding a 1.44 Mt (6.0 PJ ) bomb 400 kilometres (250 mi; 1,300,000 ft) above the mid-Pacific Ocean. This demonstrated that the effects of a high-altitude nuclear explosion were much larger than had been previously calculated. Starfish Prime made those effects known to
3348-481: The stationing of nuclear weapons in space, in addition to other weapons of mass destruction . The Comprehensive Nuclear-Test-Ban Treaty of 1996 prohibits all nuclear testing; whether over- or underground, underwater or in the atmosphere, but hasn't entered into force yet as it hasn't been ratified by some of the states party to the Treaty. The strong electromagnetic pulse (EMP) that results has several components. In
3410-459: The sturdy telephone system from the other Hawaiian islands. The radius for an effective satellite kill for the Compton radiation produced by such a nuclear weapon in space was determined to be roughly 80 kilometres (50 mi). Further testing to this end was carried out, and embodied in a Department of Defense program, Program 437 . . There are problems with nuclear weapons carried over to testing and deployment scenarios, however. Because of
3472-467: The time duration and occurrence of each pulse. E1 is the fastest or "early time" high-altitude EMP. Traditionally, the term "EMP" often refers specifically to this E1 component of high-altitude electromagnetic pulse. The E2 and E3 pulses are often further subdivided into additional divisions according to causation. E2 is a much lower intensity "intermediate time" EMP, which is further divided into E2A (scattered gamma EMP) and E2B (neutron gamma EMP). E3
3534-473: The time of the explosion that paralyzed the recording equipment." During British nuclear testing in 1952–53, instrumentation failures were attributed to " radioflash ", which was their term for EMP. The first openly reported observation of the unique aspects of high-altitude nuclear EMP occurred during the helium balloon -lofted Yucca nuclear test of the Hardtack I series on 28 April 1958. In that test,
3596-508: The very large radius associated with nuclear events, it was nearly impossible to prevent indiscriminate damage to other satellites, including one's own satellites. Starfish Prime produced an artificial radiation belt in space that soon destroyed three satellites ( Ariel , TRAAC , and Transit 4B all failed after traversing the radiation belt, while Cosmos V , Injun I and Telstar 1 suffered minor degradation, due to some radiation damage to solar cells , etc.). The radiation dose rate
3658-462: Was at least 0.6 Gy /day at four months after Starfish for a well-shielded satellite or crewed capsule in a polar circular earth orbit , which caused NASA concern with regard to its crewed space exploration programs. In general, nuclear effects in space (or very high altitudes) have a qualitatively different display. While an atmospheric nuclear explosion has a characteristic mushroom-shaped cloud , high-altitude and space explosions tend to manifest
3720-588: Was communicated informally to US scientists. For a few years US and Russian scientists collaborated on the HEMP phenomenon. Funding was secured to enable Russian scientists to report on some of the Soviet EMP results in international scientific journals. As a result, formal documentation of some of the EMP damage in Kazakhstan exists, although it is still sparse in the open-scientific literature. For one of
3782-563: Was relatively weak compared to what could be produced with a more intense pulse, and in part due to the relative ruggedness (compared to today) of Hawaii's electrical and electronic infrastructure in 1962. The relatively small magnitude of the Starfish Prime EMP in Hawaii (about 5.6 kilovolts/metre) and the relatively small amount of damage (for example, only 1% to 3% of streetlights extinguished) led some scientists to believe, in
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#17327728984083844-474: Was vertically polarized. In spite of these many differences, the unique EMP results were dismissed as a possible wave propagation anomaly. The high-altitude nuclear tests of 1962, as discussed below, confirmed the unique results of the Yucca high-altitude test and increased the awareness of high-altitude nuclear EMP beyond the original group of defense scientists. The larger scientific community became aware of
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