RDS-37 was the Soviet Union 's first two-stage hydrogen bomb , first tested on 22 November 1955. The weapon had a nominal yield of approximately 3 megatons . It was scaled down to 1.6 megatons for the live test.
125-538: The RDS-37 was a reaction to the efforts of the United States. Previously, the Soviet Union allegedly used many of their spies in the U.S. to help them generate methods and ideas for the nuclear bomb . The creation of the hydrogen bomb required less usage of this method, although they still received help from some spies, most importantly, Klaus Fuchs . In 1945, the Soviet Union reached a decision to work on
250-513: A misnomer , as their energy comes from the nucleus of the atom, just as it does with fusion weapons. In fission weapons, a mass of fissile material ( enriched uranium or plutonium ) is forced into supercriticality —allowing an exponential growth of nuclear chain reactions —either by shooting one piece of sub-critical material into another (the "gun" method) or by compression of a sub-critical sphere or cylinder of fissile material using chemically fueled explosive lenses . The latter approach,
375-665: A policy of deliberate ambiguity , it does not acknowledge having them. Germany , Italy , Turkey , Belgium , the Netherlands , and Belarus are nuclear weapons sharing states. South Africa is the only country to have independently developed and then renounced and dismantled its nuclear weapons. The Treaty on the Non-Proliferation of Nuclear Weapons aims to reduce the spread of nuclear weapons, but there are different views of its effectiveness. There are two basic types of nuclear weapons: those that derive
500-545: A 'levitated' sphere in its center. Part of the expensive plutonium was replaced with less expensive uranium-235. Levitation increased the energy yield and made it possible to reduce the size and weight of the explosive. Similar achievements were achieved without espionage by the Soviet Laboratories." The initial alarm-clock method derived by Teller was assessed by Stanislaw Ulam , who decided that it would be more difficult and costlier than expected. During this time
625-600: A combination of fission and fusion reactions ( thermonuclear bomb ), producing a nuclear explosion . Both bomb types release large quantities of energy from relatively small amounts of matter . The first test of a fission ("atomic") bomb released an amount of energy approximately equal to 20,000 tons of TNT (84 TJ ). The first thermonuclear ("hydrogen") bomb test released energy approximately equal to 10 million tons of TNT (42 PJ). Nuclear bombs have had yields between 10 tons TNT (the W54 ) and 50 megatons for
750-696: A conference—called for in the manifesto—in Pugwash, Nova Scotia , Eaton's birthplace. This conference was to be the first of the Pugwash Conferences on Science and World Affairs , held in July 1957. By the 1960s, steps were taken to limit both the proliferation of nuclear weapons to other countries and the environmental effects of nuclear testing . The Partial Nuclear Test Ban Treaty (1963) restricted all nuclear testing to underground nuclear testing , to prevent contamination from nuclear fallout, whereas
875-426: A design for a "super bomb". Also in 1945, Enrico Fermi gave lectures at Los Alamos discussing the fusion process. At the end of his lecture he stated "so far all schemes for the initiation of the super [are] rather vague". In the spring of 1946, Edward Teller set up a conference to assess all the information known about the hydrogen bomb. Klaus Fuchs attended this same conference. In the same year, Teller postulated
1000-472: A device layout which incorporated the principle of a two-stage nuclear charge". Many people questioned whether they could be successful from the very beginning. Questions concerning the two-stage nuclear charge fell into two categories. The first set of questions concerned nuclear implosion. The first module, or fission trigger, initiated "by compression of nuclear material or fission and fusion of materials by spherical explosion of chemical explosives, in which
1125-458: A faster and less vulnerable attack, the development of long-range intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs) has given some nations the ability to plausibly deliver missiles anywhere on the globe with a high likelihood of success. More advanced systems, such as multiple independently targetable reentry vehicles (MIRVs), can launch multiple warheads at different targets from one missile, reducing
1250-614: A few nations possess such weapons or are suspected of seeking them. The only countries known to have detonated nuclear weapons—and acknowledge possessing them—are (chronologically by date of first test) the United States , the Soviet Union (succeeded as a nuclear power by Russia ), the United Kingdom , France , China , India , Pakistan , and North Korea . Israel is believed to possess nuclear weapons, though, in
1375-492: A fission bomb to initiate them. Such a device might provide a simpler path to thermonuclear weapons than one that required the development of fission weapons first, and pure fusion weapons would create significantly less nuclear fallout than other thermonuclear weapons because they would not disperse fission products. In 1998, the United States Department of Energy divulged that the United States had, "...made
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#17327837475051500-421: A fusion weapon as of January 2016 , though this claim is disputed. Thermonuclear weapons are considered much more difficult to successfully design and execute than primitive fission weapons. Almost all of the nuclear weapons deployed today use the thermonuclear design because it results in an explosion hundreds of times stronger than that of a fission bomb of similar weight. Thermonuclear bombs work by using
1625-404: A given EM signal may be sharply defined, as is seen in atomic spectra , or may be broad, as in blackbody radiation . In the particle picture, the energy carried by each photon is proportional to its frequency. In the wave picture, the energy of a monochromatic wave is proportional to its intensity . This implies that if two EM waves have the same intensity, but different frequencies, the one with
1750-484: A lot of credibility and prestige among his co-workers and superiors. Following his success, he was given more autonomy in his research and made significant contributions in the realm of nuclear weaponry (and industry). His studies and theories on magnetic plasma confinement and on the magnetic thermonuclear reactor eventually led to the introduction of large electromagnetic pulse devices and laser fusion . Many of Sakharov's works and proposed ideas during his time working on
1875-472: A nation's economic electronics-based infrastructure. Because the effect is most effectively produced by high altitude nuclear detonations (by military weapons delivered by air, though ground bursts also produce EMP effects over a localized area), it can produce damage to electronics over a wide, even continental, geographical area. Research has been done into the possibility of pure fusion bombs : nuclear weapons that consist of fusion reactions without requiring
2000-414: A new design for the hydrogen bomb, which he called the "Alarm Clock", which he suggested would use lithium-6 deuteride instead of pure deuterium . Klaus Fuchs had passed on information about both the nuclear bomb and the hydrogen bomb to the Soviet Union. This information resulted in the recruitment of Igor Tamm ’s group, whose work helped create the hydrogen bomb. The content that Fuchs provided in 1948
2125-537: A new nuclear strategy, one that is distinct from that which gave relative stability during the Cold War. Since 1996, the United States has had a policy of allowing the targeting of its nuclear weapons at terrorists armed with weapons of mass destruction . Robert Gallucci argues that although traditional deterrence is not an effective approach toward terrorist groups bent on causing a nuclear catastrophe, Gallucci believes that "the United States should instead consider
2250-438: A nuclear bomb, which was the primary unit, and a secondary energy unit. The first stage of the hydrogen bomb resembled the layer-cake design, except the main difference is that the initiation is carried out by a nuclear device, rather than a conventional explosive. This design was initially postulated by Enrico Fermi and Edward Teller in 1941. Teller insisted that they should ignite deuterium by some fission weapon. The hydrogen bomb
2375-425: A nuclear war between two nations would result in mutual annihilation. From this point of view, the significance of nuclear weapons is to deter war because any nuclear war would escalate out of mutual distrust and fear, resulting in mutually assured destruction . This threat of national, if not global, destruction has been a strong motivation for anti-nuclear weapons activism. Critics from the peace movement and within
2500-411: A nuclear weapon from another country by threatening nuclear retaliation is known as the strategy of nuclear deterrence . The goal in deterrence is to always maintain a second strike capability (the ability of a country to respond to a nuclear attack with one of its own) and potentially to strive for first strike status (the ability to destroy an enemy's nuclear forces before they could retaliate). During
2625-465: A nuclear weapon is a gravity bomb dropped from aircraft ; this was the method used by the United States against Japan in 1945. This method places few restrictions on the size of the weapon. It does, however, limit attack range, response time to an impending attack, and the number of weapons that a country can field at the same time. With miniaturization, nuclear bombs can be delivered by both strategic bombers and tactical fighter-bombers . This method
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#17327837475052750-409: A nuclear weapon to its target is an important factor affecting both nuclear weapon design and nuclear strategy . The design, development, and maintenance of delivery systems are among the most expensive parts of a nuclear weapons program; they account, for example, for 57% of the financial resources spent by the United States on nuclear weapons projects since 1940. The simplest method for delivering
2875-433: A nuclear weapon with suitable materials (such as cobalt or gold ) creates a weapon known as a salted bomb . This device can produce exceptionally large quantities of long-lived radioactive contamination . It has been conjectured that such a device could serve as a "doomsday weapon" because such a large quantity of radioactivities with half-lives of decades, lifted into the stratosphere where winds would distribute it around
3000-607: A paper in January 1949 where he noted that the deuterium – tritium and deuterium – deuterium reaction cross sections had not been studied experimentally and all assessments were conjectural. In March 1949 Khariton requested to Beria that Tamm and Kompaneets be given access to the intelligence data with the D–T cross-sections. This was refused to minimize the access to intelligence materials but instead on 27 April D–T cross-section measurements were sent to Tamm and Kompaneets without mentioning
3125-421: A policy of expanded deterrence, which focuses not solely on the would-be nuclear terrorists but on those states that may deliberately transfer or inadvertently leak nuclear weapons and materials to them. By threatening retaliation against those states, the United States may be able to deter that which it cannot physically prevent.". Graham Allison makes a similar case, arguing that the key to expanded deterrence
3250-421: A reply, stating: As regards the material No. 713a, the basic ideas about the role of tritium in the transfer of explosion from a uranium-235 primer to deuterium, about the necessity of careful selection of uranium primer power, and about the role of particles and photons in the transfer of the explosion to deuterium are new. These materials are valuable in that they will be helpful to Cde. Zel’dovich in his work on
3375-447: A significant portion of their energy from fission reactions used to "trigger" fusion reactions, and fusion reactions can themselves trigger additional fission reactions. Only six countries—the United States , Russia , the United Kingdom , China , France , and India —have conducted thermonuclear weapon tests. Whether India has detonated a "true" multi-staged thermonuclear weapon is controversial. North Korea claims to have tested
3500-464: A stream of photons , radiant energy can be viewed as photon energy – the energy carried by these photons. Alternatively, EM radiation can be viewed as an electromagnetic wave, which carries energy in its oscillating electric and magnetic fields. These two views are completely equivalent and are reconciled to one another in quantum field theory (see wave-particle duality ). EM radiation can have various frequencies . The bands of frequency present in
3625-550: A substantial investment" in the past to develop pure fusion weapons, but that, "The U.S. does not have and is not developing a pure fusion weapon", and that, "No credible design for a pure fusion weapon resulted from the DOE investment". Nuclear isomers provide a possible pathway to fissionless fusion bombs. These are naturally occurring isotopes ( Hf being a prominent example) which exist in an elevated energy state. Mechanisms to release this energy as bursts of gamma radiation (as in
3750-458: A thermonuclear fuel to replace the deuterium–tritium fuel that was decided upon after publication of the Teller–Ulam tests. Several factors had to be overcome by Design Bureau 11 in implementing the idea of atomic compression. The main problems dealt with the massive amounts of radiation that would be emitted from the initial atomic bomb implosion. The calculated yields were large enough that there
3875-464: A thermonuclear fuel. Sakharov developed his own compression method completely independent of the Teller-Ulam design. Sakharov's design for atomic compression utilized several tightly packed layers of either deuterium-deuterium or deuterium-tritium that would initiate inwardly, achieving an atomic compression. In theory, an atomic initiator would be positioned in the center of a spherical housing that
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4000-463: A traditional Russian, multi-layered cake that was tightly held together by a thick cream. The main problem with his idea was that the reaction cross sections of deuterium-deuterium and deuterium-tritium reactions were not known, and only theorized about. Design Bureau 11 (KB-11) presented the idea for the RDS-6 bomb design to USSR officials using primarily theoretical calculations. Andrei Sakharov published
4125-480: A two-stage thermonuclear weapon. The measured energy yield of the device was equivalent to that of 1.6 megatons of TNT. After the test, the commission noted three things during the meeting on 24 November 1955, "the design of the hydrogen bomb, based on a novel principle, has been successfully tested; it is necessary to continue detailed studies of the processes proceeding in explosions of bombs of this type; further development of hydrogen bombs should be conducted on
4250-420: Is a thermonuclear weapon that yields a relatively small explosion but a relatively large amount of neutron radiation . Such a weapon could, according to tacticians, be used to cause massive biological casualties while leaving inanimate infrastructure mostly intact and creating minimal fallout. Because high energy neutrons are capable of penetrating dense matter, such as tank armor, neutron warheads were procured in
4375-456: Is analogous to identifying a criminal by fingerprints. "The goal would be twofold: first, to deter leaders of nuclear states from selling weapons to terrorists by holding them accountable for any use of their weapons; second, to give leaders every incentive to tightly secure their nuclear weapons and materials." According to the Pentagon's June 2019 " Doctrine for Joint Nuclear Operations " of
4500-403: Is coming up with ways of tracing nuclear material to the country that forged the fissile material. "After a nuclear bomb detonates, nuclear forensics cops would collect debris samples and send them to a laboratory for radiological analysis. By identifying unique attributes of the fissile material, including its impurities and contaminants, one could trace the path back to its origin." The process
4625-498: Is emitted from a warm element (floor, wall, overhead panel) and warms people and other objects in rooms rather than directly heating the air. Because of this, the air temperature may be lower than in a conventionally heated building, even though the room appears just as comfortable. Various other applications of radiant energy have been devised. These include treatment and inspection, separating and sorting, medium of control, and medium of communication. Many of these applications involve
4750-481: Is for the purpose of achieving different yields for different situations , and in manipulating design elements to attempt to minimize weapon size, radiation hardness or requirements for special materials, especially fissile fuel or tritium. Some nuclear weapons are designed for special purposes; most of these are for non-strategic (decisively war-winning) purposes and are referred to as tactical nuclear weapons . The neutron bomb purportedly conceived by Sam Cohen
4875-503: Is no evidence that it is feasible beyond the military domain. However, the U.S. Air Force funded studies of the physics of antimatter in the Cold War , and began considering its possible use in weapons, not just as a trigger, but as the explosive itself. A fourth generation nuclear weapon design is related to, and relies upon, the same principle as antimatter-catalyzed nuclear pulse propulsion . Most variation in nuclear weapon design
5000-409: Is not a fusion bomb. In the boosted bomb, the neutrons produced by the fusion reactions serve primarily to increase the efficiency of the fission bomb. There are two types of boosted fission bomb: internally boosted, in which a deuterium-tritium mixture is injected into the bomb core, and externally boosted, in which concentric shells of lithium-deuteride and depleted uranium are layered on the outside of
5125-490: Is not clear that this has ever been implemented, and their plausible use in nuclear weapons is a matter of dispute. The other basic type of nuclear weapon produces a large proportion of its energy in nuclear fusion reactions. Such fusion weapons are generally referred to as thermonuclear weapons or more colloquially as hydrogen bombs (abbreviated as H-bombs ), as they rely on fusion reactions between isotopes of hydrogen ( deuterium and tritium ). All such weapons derive
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5250-573: Is redirected or redistributed as well. Radiant energy is one of the mechanisms by which energy can enter or leave an open system . Such a system can be man-made, such as a solar energy collector, or natural, such as the Earth's atmosphere . In geophysics , most atmospheric gases, including the greenhouse gases , allow the Sun's short-wavelength radiant energy to pass through to the Earth's surface, heating
5375-496: Is sometimes used to refer to the electromagnetic waves themselves , rather than their energy (a property of the waves). In the past, the term "electro-radiant energy" has also been used. The term "radiant energy" also applies to gravitational radiation . For example, the first gravitational waves ever observed were produced by a black hole collision that emitted about 5.3 × 10 joules of gravitational-wave energy. Because electromagnetic (EM) radiation can be conceptualized as
5500-400: Is the joule (J). The quantity of radiant energy may be calculated by integrating radiant flux (or power ) with respect to time . The symbol Q e is often used throughout literature to denote radiant energy ("e" for "energetic", to avoid confusion with photometric quantities). In branches of physics other than radiometry, electromagnetic energy is referred to using E or W . The term
5625-454: Is the primary means of nuclear weapons delivery; the majority of U.S. nuclear warheads, for example, are free-fall gravity bombs, namely the B61 , which is being improved upon to this day. Preferable from a strategic point of view is a nuclear weapon mounted on a missile , which can use a ballistic trajectory to deliver the warhead over the horizon. Although even short-range missiles allow for
5750-471: Is used particularly when electromagnetic radiation is emitted by a source into the surrounding environment. This radiation may be visible or invisible to the human eye. The term "radiant energy" is most commonly used in the fields of radiometry , solar energy , heating and lighting , but is also sometimes used in other fields (such as telecommunications ). In modern applications involving transmission of power from one location to another, "radiant energy"
5875-695: The Starfish Prime high-altitude nuclear test in 1962, an unexpected effect was produced which is called a nuclear electromagnetic pulse . This is an intense flash of electromagnetic energy produced by a rain of high-energy electrons which in turn are produced by a nuclear bomb's gamma rays. This flash of energy can permanently destroy or disrupt electronic equipment if insufficiently shielded. It has been proposed to use this effect to disable an enemy's military and civilian infrastructure as an adjunct to other nuclear or conventional military operations. By itself it could as well be useful to terrorists for crippling
6000-535: The Treaty on the Non-Proliferation of Nuclear Weapons (1968) attempted to place restrictions on the types of activities signatories could participate in, with the goal of allowing the transference of non-military nuclear technology to member countries without fear of proliferation. Radiant energy In physics , and in particular as measured by radiometry , radiant energy is the energy of electromagnetic and gravitational radiation . As energy, its SI unit
6125-554: The Tsar Bomba (see TNT equivalent ). A thermonuclear weapon weighing as little as 600 pounds (270 kg) can release energy equal to more than 1.2 megatonnes of TNT (5.0 PJ). A nuclear device no larger than a conventional bomb can devastate an entire city by blast, fire, and radiation . Since they are weapons of mass destruction , the proliferation of nuclear weapons is a focus of international relations policy. Nuclear weapons have been deployed twice in war , both by
6250-676: The Tsar Bomba of the USSR, which released an energy equivalent of over 50 megatons of TNT (210 PJ), was a three-stage weapon. Most thermonuclear weapons are considerably smaller than this, due to practical constraints from missile warhead space and weight requirements. In the early 1950s the Livermore Laboratory in the United States had plans for the testing of two massive bombs, Gnomon and Sundial , 1 gigaton of TNT and 10 gigatons of TNT respectively. Fusion reactions do not create fission products, and thus contribute far less to
6375-424: The hafnium controversy ) have been proposed as possible triggers for conventional thermonuclear reactions. Antimatter , which consists of particles resembling ordinary matter particles in most of their properties but having opposite electric charge , has been considered as a trigger mechanism for nuclear weapons. A major obstacle is the difficulty of producing antimatter in large enough quantities, and there
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#17327837475056500-553: The head of government or head of state . Despite controls and regulations governing nuclear weapons, there is an inherent danger of "accidents, mistakes, false alarms, blackmail, theft, and sabotage". In the late 1940s, lack of mutual trust prevented the United States and the Soviet Union from making progress on arms control agreements. The Russell–Einstein Manifesto was issued in London on July 9, 1955, by Bertrand Russell in
6625-436: The tropopause into the stratosphere , where the calm non-turbulent winds permit the debris to travel great distances from the burst, eventually settling and unpredictably contaminating areas far removed from the target of the explosion. There are other types of nuclear weapons as well. For example, a boosted fission weapon is a fission bomb that increases its explosive yield through a small number of fusion reactions, but it
6750-537: The "implosion" method, is more sophisticated and more efficient (smaller, less massive, and requiring less of the expensive fissile fuel) than the former. A major challenge in all nuclear weapon designs is to ensure that a significant fraction of the fuel is consumed before the weapon destroys itself. The amount of energy released by fission bombs can range from the equivalent of just under a ton to upwards of 500,000 tons (500 kilotons ) of TNT (4.2 to 2.1 × 10 GJ). All fission reactions generate fission products ,
6875-586: The 1980s (though not deployed in Europe) for use as tactical payloads for US Army artillery shells (200 mm W79 and 155 mm W82 ) and short range missile forces. Soviet authorities announced similar intentions for neutron warhead deployment in Europe; indeed, they claimed to have originally invented the neutron bomb, but their deployment on USSR tactical nuclear forces is unverifiable. A type of nuclear explosive most suitable for use by ground special forces
7000-635: The American counterpart energy yield predictions were off by a factor of two and a half in the Castle Bravo test. The Soviets also delivered a weapon-ready design for the RDS-37. On the American side of the arms race, the bombs being tested were remotely detonated. "The test was the culmination of many years of labor, a triumph that has opened the way to the development of a whole range of devices with diverse high-performance characteristics." The report on
7125-533: The Americans, but also able to outperform them in some key areas of weapon and technological development. The RDS program gave rise to the genius of Andrei Sakharov, who undoubtedly was the driving force behind the Soviet thermonuclear weapons development program. During his time at Design Bureau 11, Sakharov formulated the most critical ideas for the advancement of Soviet thermonuclear projects. RDS-37 gave Sakharov
7250-425: The Cold War, policy and military theorists considered the sorts of policies that might prevent a nuclear attack, and they developed game theory models that could lead to stable deterrence conditions. Different forms of nuclear weapons delivery (see above) allow for different types of nuclear strategies. The goals of any strategy are generally to make it difficult for an enemy to launch a pre-emptive strike against
7375-494: The Joint Chiefs of Staffs website Publication, "Integration of nuclear weapons employment with conventional and special operations forces is essential to the success of any mission or operation." Because they are weapons of mass destruction, the proliferation and possible use of nuclear weapons are important issues in international relations and diplomacy. In most countries, the use of nuclear force can only be authorized by
7500-503: The Nuclear Age (1961) that mere possession of a nuclear arsenal was enough to ensure deterrence, and thus concluded that the spread of nuclear weapons could increase international stability . Some prominent neo-realist scholars, such as Kenneth Waltz and John Mearsheimer , have argued, along the lines of Gallois, that some forms of nuclear proliferation would decrease the likelihood of total war , especially in troubled regions of
7625-586: The RDS projects are still ongoing today. Video showing the detonation of RDS-37 is often confused with video of the Tsar Bomba , although they can be quite similar. RDS-37 videos have the detonation in the center, and Tsar Bomba videos have the detonation to the right (except for the mushroom-cloud video, which is in the center) . In addition, the RDS-37 test occurred in the Semipalatinsk test area, and some of
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#17327837475057750-453: The RDS-37 was a "shining example of creative teamwork". The report went on further to boast enormous amounts of design-oriented, experimental, and technological efforts carried out under the supervision of Design Bureau 11's chief designer, Yulii Borisovich Khariton . The RDS-37 was assembled as an air-deliverable bomb. In the initial testing phase, the bomb's energy yield was reduced out of safety concerns. The lithium deuteride fusion cell
7875-416: The RDS-37, written by Zel'dovich and Sakharov, stated that the new principle of atomic compression as seen in the RDS-37 was a "shining example of creative teamwork." The report boasted enormous amounts of design-oriented, experimental and technological efforts carried out under the supervision of Design Bureau 11's chief designer, Khariton. The successful detonation of the first two-stage thermonuclear weapon
8000-406: The Soviet Union began to fully consider the two-stage bomb. However, in 1954, the plan was finally realized. Prior to 1954, the thermonuclear device was not thought to be initiated by radiation, but by a shock wave. On 1 November 1952, the United States tested their first "hydrogen bomb", codenamed Ivy Mike . The design was based on the Teller–Ulam layout. Ivy Mike was not a usable weapon. It
8125-417: The Soviet Union possessed a weapon that could destroy any target in the United States. The thermonuclear weapons race between the United States and the Soviet Union exceeded all expectations set out before the scientists who took part. Two countries creating thermonuclear weapons with such energy yields from two different design methods proved to be the crowning achievement for science in the 1950s . Of course,
8250-664: The USAAF detonated a plutonium implosion-type fission bomb nicknamed " Fat Man " over the Japanese city of Nagasaki . These bombings caused injuries that resulted in the deaths of approximately 200,000 civilians and military personnel . The ethics of these bombings and their role in Japan's surrender are to this day, still subjects of debate . Since the atomic bombings of Hiroshima and Nagasaki , nuclear weapons have been detonated over 2,000 times for testing and demonstration. Only
8375-777: The USAF AIR-2 Genie , the AIM-26 Falcon and US Army Nike Hercules . Missile interceptors such as the Sprint and the Spartan also used small nuclear warheads (optimized to produce neutron or X-ray flux) but were for use against enemy strategic warheads. Other small, or tactical, nuclear weapons were deployed by naval forces for use primarily as antisubmarine weapons. These included nuclear depth bombs or nuclear armed torpedoes. Nuclear mines for use on land or at sea are also possibilities. The system used to deliver
8500-527: The United States against the Japanese cities of Hiroshima and Nagasaki in 1945 during World War II . Nuclear weapons have only twice been used in warfare, both times by the United States against Japan at the end of World War II . On August 6, 1945, the United States Army Air Forces (USAAF) detonated a uranium gun-type fission bomb nicknamed " Little Boy " over the Japanese city of Hiroshima ; three days later, on August 9,
8625-414: The United States also did not fully understand their own designs. The Soviet Union set up a group to work on the hydrogen bomb. In August 1948, Andrei Sakharov postulated the sloyka , or layer cake method, which consisted of alternating layers of uranium and thermonuclear fuel. In early 1949, this layer-cake design was tweaked, with lithium-6 deuteride as the thermonuclear fuel. In early 1950, Klaus Fuchs
8750-461: The United States prompted Soviet retaliation, and the Soviets quickly attempted to catch up. Although the Soviet Union had detonated their RDS-6 around that same time, the RDS-6 was initiated by high-powered explosives, while Ivy Mike was initiated by radiation method. The Soviets then abandoned their layered-cake method and focused on a two-stage bomb method. The hydrogen bomb primarily has 2 units:
8875-593: The United States were focused on the Alarm Clock, while the Soviet Union were focusing on the Sloyka method. The alarm-clock dilemma lasted until 1951, when Ulam came up with the idea of compressing a thermonuclear secondary with the hydrodynamic shock produced by a primary fission bomb. Teller agreed with this method and even altered it by using the pressure from the radiation from the primary, rather than hydrodynamic shock. After Teller had finally accepted this method,
9000-526: The United States. Small, two-man portable tactical weapons (somewhat misleadingly referred to as suitcase bombs ), such as the Special Atomic Demolition Munition , have been developed, although the difficulty of combining sufficient yield with portability limits their military utility. Nuclear warfare strategy is a set of policies that deal with preventing or fighting a nuclear war. The policy of trying to prevent an attack by
9125-448: The arms race with the United States. A large part of this was due to the fact that the Soviet Union was the first nation to successfully employ the use of lithium deuterium as a thermonuclear fuel. Another important factor to consider was the accuracy with which the Soviets were able to predict the energy yields of their bombs. The predictions for the RDS-6 tests were accurate up to 30% and the RDS-37 tests were accurate to within 10%, whereas
9250-482: The basis of a broad application of the principles chosen as the foundation of the RDS-37 bomb". The successful testing of the RDS-37 made it possible to start large-scale development of thermonuclear weapons. The charge of the RDS-37 became the prototype for all of the following two-stage thermonuclear devices in the USSR. The RDS-37 tests at the Semipalatinsk Site proved to bring the Soviet Union back into
9375-598: The breaking of the windows (confirmation needed as it is an assumption by common sense) caused by the explosion. A scientist in Andrei Sakharov's theoretical lab recalled the test in a collective book of memoirs. He witnessed the RDS-37 test from a viewing station thirty-two kilometers (20 miles) away from the hypocenter. As the countdown reached zero, the first impression he had "was of almost intolerable heat, as if [his head] had been placed into an open oven for several seconds." The shock wave of dust and debris caused by
9500-485: The chance of a successful missile defense . Today, missiles are most common among systems designed for delivery of nuclear weapons. Making a warhead small enough to fit onto a missile, though, can be difficult. Tactical weapons have involved the most variety of delivery types, including not only gravity bombs and missiles but also artillery shells, land mines , and nuclear depth charges and torpedoes for anti-submarine warfare . An atomic mortar has been tested by
9625-435: The creation of nuclear fallout than fission reactions, but because all thermonuclear weapons contain at least one fission stage, and many high-yield thermonuclear devices have a final fission stage, thermonuclear weapons can generate at least as much nuclear fallout as fission-only weapons. Furthermore, high yield thermonuclear explosions (most dangerously ground bursts) have the force to lift radioactive debris upwards past
9750-455: The decision process. The prospect of mutually assured destruction might not deter an enemy who expects to die in the confrontation. Further, if the initial act is from a stateless terrorist instead of a sovereign nation, there might not be a nation or specific target to retaliate against. It has been argued, especially after the September 11, 2001, attacks , that this complication calls for
9875-469: The energy of a fission bomb to compress and heat fusion fuel. In the Teller-Ulam design , which accounts for all multi-megaton yield hydrogen bombs, this is accomplished by placing a fission bomb and fusion fuel ( tritium , deuterium , or lithium deuteride ) in proximity within a special, radiation-reflecting container. When the fission bomb is detonated, gamma rays and X-rays emitted first compress
10000-625: The energy of the explosion of the nuclear charge (the primary module) is generated in the form of X-ray radiation; the energy of the X-ray radiation is transported to the fusion module; the implosion of the fusion module using the energy of the 'delivered' X-ray radiation". Hopes for a better compression of nuclear material that could be initiated had been in discussion since the early 1950s. Not long after, Yakov Borisovich Zel'dovich and Andrei Sakharov started to work on this theory. "In January 1954, Ya. B. Zeldovich and A. D. Sakharov considered in detail
10125-430: The explosion could be seen and heard approaching and reached the viewing station roughly ninety seconds after the thermonuclear detonation. All viewers were forced to fall down on their faces with their feet pointed toward the explosion to help avoid injury from flying debris. After the shock wave passed, all the viewers stood up and started cheering their success, the Soviet Union became the first to successfully air deliver
10250-455: The fission bomb core. The external method of boosting enabled the USSR to field the first partially thermonuclear weapons, but it is now obsolete because it demands a spherical bomb geometry, which was adequate during the 1950s arms race when bomber aircraft were the only available delivery vehicles. The detonation of any nuclear weapon is accompanied by a blast of neutron radiation . Surrounding
10375-416: The form of X-rays, which were directed in such a way that they would provide all the required energy to initiate the thermonuclear charge. The technical specifications for the bomb design were completed by 3 February 1955 but were continuously reevaluated and improved up until RDS-37 was delivered to the test site in Semipalatinsk. It was during this time that KB-11 found that they could use lithium–deuterium as
10500-420: The fusion fuel, then heat it to thermonuclear temperatures. The ensuing fusion reaction creates enormous numbers of high-speed neutrons , which can then induce fission in materials not normally prone to it, such as depleted uranium . Each of these components is known as a "stage", with the fission bomb as the "primary" and the fusion capsule as the "secondary". In large, megaton-range hydrogen bombs, about half of
10625-535: The globe, would make all life on the planet extinct. In connection with the Strategic Defense Initiative , research into the nuclear pumped laser was conducted under the DOD program Project Excalibur but this did not result in a working weapon. The concept involves the tapping of the energy of an exploding nuclear bomb to power a single-shot laser that is directed at a distant target. During
10750-443: The ground and oceans. The absorbed solar energy is partly re-emitted as longer wavelength radiation (chiefly infrared radiation), some of which is absorbed by the atmospheric greenhouse gases. Radiant energy is produced in the sun as a result of nuclear fusion . Radiant energy is used for radiant heating . It can be generated electrically by infrared lamps , or can be absorbed from sunlight and used to heat water. The heat energy
10875-557: The higher frequency "contains" fewer photons, since each photon is more energetic. When EM waves are absorbed by an object, the energy of the waves is converted to heat (or converted to electricity in case of a photoelectric material). This is a very familiar effect, since sunlight warms surfaces that it irradiates. Often this phenomenon is associated particularly with infrared radiation, but any kind of electromagnetic radiation will warm an object that absorbs it. EM waves can also be reflected or scattered , in which case their energy
11000-518: The inner element of the RDS-6s charge for the basic physical element of the secondary module, i.e. the 'layered' spherical configuration of the system". The Soviet Union was able to form some similar achievements to the United States without the help of outside information. "The active material, instead of being a solid sphere to begin with, as in the Nagasaki bomb , would be fabricated as a shell, with
11125-462: The liquid phase with moderate cooling or under mild pressure, but its physical properties were not well known at that point. The problem with liquid deuterium was the technology to transfer and store it in bulk quantities was not yet developed. The United States decided to choose liquid deuterium as their thermonuclear fuel. This was the premise behind the Ivy Mike bomb. The detonation of Ivy Mike by
11250-485: The main body. Calculations show that for radiation is emitted very strongly. Conversion of radiant energy into mechanical energy to compress the main body. These principles have been developed through the efforts of Sectors No. 2. and No. 1. On 22 November 1955, the Russians tested their first true two-stage hydrogen bomb in the megaton range, the RDS-37. This test implemented the two-stage radiation implosion. This
11375-455: The main body. It is postulated [deleted]. These principles have been developed through the team efforts of Sectors No. 2 and No. 1 (Ya. B. Zel’dovich, Yu. A. Trutnev, and A. D. Sakharov)...". This problem with a two-stage nuclear charge brings about two other problems. One, "what is now the carrier of the explosive energy of the original source?". Two, "how is this energy transported to the secondary module?". The second set of questions concerns
11500-496: The majority of their energy from nuclear fission reactions alone, and those that use fission reactions to begin nuclear fusion reactions that produce a large amount of the total energy output. All existing nuclear weapons derive some of their explosive energy from nuclear fission reactions. Weapons whose explosive output is exclusively from fission reactions are commonly referred to as atomic bombs or atom bombs (abbreviated as A-bombs ). This has long been noted as something of
11625-475: The megaton range. The first of these was Castle Bravo , which eventually turned out as the largest detonation by the United States ever. By spring of 1954, the Soviet scientists began to understand the possibility of releasing radiation from the nuclear-bomb trigger and using it to initiate the fusion part of the bomb. This idea parallels the Teller–Ulam design used in the Mike detonation. They subsequently abandoned
11750-405: The megaton yield range. The RDS-37 was dropped from a Tupolev Tu-16 bomber and was used most through the late 1950s and 1960s. After a while the Soviet Union felt as if the 2.9-megaton thermonuclear bomb was excessive for some missions, so the less powerful RP-30 and RP-32 200-kiloton bombs were ready for some missions. It would take the United States until 20 May 1956, about half a year, to achieve
11875-407: The midst of the Cold War. It highlighted the dangers posed by nuclear weapons and called for world leaders to seek peaceful resolutions to international conflict. The signatories included eleven pre-eminent intellectuals and scientists, including Albert Einstein , who signed it just days before his death on April 18, 1955. A few days after the release, philanthropist Cyrus S. Eaton offered to sponsor
12000-545: The military establishment have questioned the usefulness of such weapons in the current military climate. According to an advisory opinion issued by the International Court of Justice in 1996, the use of (or threat of use of) such weapons would generally be contrary to the rules of international law applicable in armed conflict, but the court did not reach an opinion as to whether or not the threat or use would be lawful in specific extreme circumstances such as if
12125-408: The missiles before they land or implementing civil defense measures using early-warning systems to evacuate citizens to safe areas before an attack. Weapons designed to threaten large populations or to deter attacks are known as strategic weapons . Nuclear weapons for use on a battlefield in military situations are called tactical weapons . Critics of nuclear war strategy often suggest that
12250-561: The origin. Ironically similar data was published in the Physical Review issue of 15 April 1949. With this information, Sakharov and Design Bureau 11 successfully implemented atomic compression in the RDS-6 tests. On 24 December 1954, the decision for implementation of the idea of atomic compression was green-lit by Soviet officials in a new project code named RDS-37. Test site preparations and other important test operations entered
12375-438: The preparation phase at the start of 1955. For RDS-37, a new design problem made itself known, keeping the distribution of charge from the spherical implosion symmetric. This led to the development of a canonical system in which both the primary and secondary modules were placed into the same compartment to maximize the directional scattering of X-rays. The vast amounts of energy from the initial atomic initiation were transferred in
12500-498: The question remained. Which thermonuclear fuel would be involved. The three main choices were lithium deuteride , deuterated ammonia and liquid deuterium . "Each had its advantages and disadvantages, lithium deuteride would be the simplest material to engineer because it was solid at room temperature, but breeding tritium within the bomb from lithium required a complex chain of thermonuclear reactions that involved only one of lithium’s several isotopes." Deuterated ammonia could be kept in
12625-428: The remains of the split atomic nuclei. Many fission products are either highly radioactive (but short-lived) or moderately radioactive (but long-lived), and as such, they are a serious form of radioactive contamination . Fission products are the principal radioactive component of nuclear fallout . Another source of radioactivity is the burst of free neutrons produced by the weapon. When they collide with other nuclei in
12750-518: The same results through the Cherokee nuclear weapons test. However, by this time the USAF had several hundred multi-megaton bombs in their arsenal, and more than 1,100 aircraft able to deliver them. The device was deliberately detonated high in the air to avoid local fallout . The height of burst was 1,550 m (5,090 ft) above the ground. Despite the reduction in yield, much of its shock wave
12875-403: The secondary module impacted by the nuclear implosion of the fission trigger. At first, scientist thought that the energy of a nuclear initiation of the fission trigger in a two-stage charge would be transported by the flow of the products of the initiation as the shock wave spread through the heterogeneous structure of the secondary module. Zeldovich and Sakharov "decided to choose an analog of
13000-429: The single-stage layer-cake and tube designs, and focused entirely on the two-stage bomb project. A report on the activity of the theoretical sector No. 1 published in 1954 states: Atomic compression is being investigated theoretically in collaboration with members of sector No. 2. The main problems associated with atomic compression are in the developmental stage. Emission of radiation from the atomic bomb used to compress
13125-400: The spherical symmetry of the implosion was dictated by the initial spherically symmetric detonation of the explosive". There seemed to be no way in which "a heterogeneous structure composed of a primary source (or sources) and a compressible secondary module" could "maintain the spherically symmetric 'nuclear implosion". The following is a report by Sakharov and Romanov on 6 August, with
13250-473: The successful and promising work from both the United States and the Soviet Union only spurred each country to push for more powerful weapons, as the floodgates of thermonuclear weapon potential had been opened. This was, of course, entirely the norm at the time considering that the Cold War was in full swing. It was a significant boost to Soviet morale knowing that the Soviet Union's physicists, engineers, scientist, and great minds were able to not only compete with
13375-535: The superbomb, performed under the operations plans approved by the First Main Directorate. More effort should be put into research in that area, and a start should be made on the work on the practical design. Vannikov set out to study deuterium and its effects. Khariton also sent his reply on 5 May 1948, which urged the Soviet Union to set up a design group. At that time, very few people knew anything about hydrogen bomb design. The scientists in
13500-402: The surrounding material, the neutrons transmute those nuclei into other isotopes, altering their stability and making them radioactive. The most commonly used fissile materials for nuclear weapons applications have been uranium-235 and plutonium-239 . Less commonly used has been uranium-233 . Neptunium-237 and some isotopes of americium may be usable for nuclear explosives as well, but it
13625-498: The survival of the state were at stake. Another deterrence position is that nuclear proliferation can be desirable. In this case, it is argued that, unlike conventional weapons, nuclear weapons deter all-out war between states, and they succeeded in doing this during the Cold War between the U.S. and the Soviet Union . In the late 1950s and early 1960s, Gen. Pierre Marie Gallois of France, an adviser to Charles de Gaulle , argued in books like The Balance of Terror: Strategy for
13750-439: The title "Atomic Compression". "Atomic Compression is being investigated theoretically in collaboration with members of sector No. 2. The main problems associated with atomic compression are in the development stage. (1) Emission of radiation from the atomic bomb used to compress main body. Calculations show that for [deleted] radiation is emitted very strongly... (2) Conversion of radiant energy into mechanical energy to compress
13875-495: The video looks across the roofs of the secret city of Kurchatov , aka Semipalatinsk-16. The Tsar occurred over the southern half of the Arctic polar desert island of Novaya Zemlya , with no similar population centers within hundreds of kilometers at that time. Nuclear weapon A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions , either fission (fission bomb) or
14000-446: The weapon system and difficult to defend against the delivery of the weapon during a potential conflict. This can mean keeping weapon locations hidden, such as deploying them on submarines or land mobile transporter erector launchers whose locations are difficult to track, or it can mean protecting weapons by burying them in hardened missile silo bunkers. Other components of nuclear strategies included using missile defenses to destroy
14125-631: The world where there exists a single nuclear-weapon state. Aside from the public opinion that opposes proliferation in any form, there are two schools of thought on the matter: those, like Mearsheimer, who favored selective proliferation, and Waltz, who was somewhat more non- interventionist . Interest in proliferation and the stability-instability paradox that it generates continues to this day, with ongoing debate about indigenous Japanese and South Korean nuclear deterrent against North Korea . The threat of potentially suicidal terrorists possessing nuclear weapons (a form of nuclear terrorism ) complicates
14250-624: The yield comes from the final fissioning of depleted uranium. Virtually all thermonuclear weapons deployed today use the "two-stage" design described to the right, but it is possible to add additional fusion stages—each stage igniting a larger amount of fusion fuel in the next stage. This technique can be used to construct thermonuclear weapons of arbitrarily large yield. This is in contrast to fission bombs, which are limited in their explosive power due to criticality danger (premature nuclear chain reaction caused by too-large amounts of pre-assembled fissile fuel). The largest nuclear weapon ever detonated,
14375-433: Was a challenge, and would be more powerful and destructive than the nuclear bomb. The fusion cell itself was not very powerful, coming out to about 17.6 MeV per reaction, but the quantity of hydrogen fuel can be scaled up to make the weapon as large as desired. Andrei Sakharov served as the leading theoretical contributor to the RDS-37 project, as he was the first to quantify the theoretical gains that could be had from
14500-649: Was also the world's first air-dropped fusion-bomb test. After the Bravo Test in March 1954, Soviet scientists started to search for ways to make an effective large-yield thermonuclear bomb. After a lot of intensive research of past experience with these bombs, a new two-stage bomb was devised. The RDS-37's thermonuclear charges are founded in fundamental scientific concepts of high-energy-density physics. The principle of radiation implosion assumes three concepts. According to Ilkaev, they are: "the predominant proportion of
14625-405: Was an important moment in the Soviet Union's nuclear weapons program and helped shape the path of the program. It had shown that the gap between the United States and the Soviet Union was closing. More importantly, the nuclear yield gap had been closed. It was now a race between the nations to perfect the bomb, making it lighter, reliable, and more compact. Now, 22 November 1955, marked the date where
14750-474: Was arrested in the United Kingdom, and was unable to continue his espionage activity for the Soviet Union. The Soviet scientists had the idea to increase the deuterium density. Sakharov and his team saw the possibility of detonating a smaller nuclear bomb within the layer cake. This idea was successful, and the first implementation was used on the RDS-6s. The RDS-6s paved the way for the RDS-37. By 1952,
14875-525: Was focused back downward at the ground unexpectedly because the weapon detonated under an inversion layer , causing a trench to collapse on a group of soldiers, killing one. It also caused a building in Kurchatov , 65 km (40 mi) away, to collapse killing a young girl. A group of forty two individuals in Kurchatov were also recorded as having been injured from the glass fragments flying out due to
15000-457: Was massive in size, weighing 82 tons. On 12 August 1953, the Soviets had tested their own "hydrogen bomb" in a test code named " Joe 4 ", which was based on the layer-cake design. By this time no one had created a "true" hydrogen bomb. All other tests had a kiloton yield. In the spring of 1954, the US tested a series of six nuclear devices, known as Operation Castle , with each experiment being in
15125-417: Was modified to replace some fusion fuel with a passive material. RDS-37 was first detonated on 22 November 1955. The weapon was air-dropped at Semipalatinsk Test Site , Kazakhstan, making it the first air-dropped two-stage thermonuclear test. It was the largest detonation ever carried out at the Semipalatinsk test site. The RDS-6s device (Joe-4) test in 1953 had one-stage design, and was not scalable into
15250-406: Was much concern whether or not a structure could be engineered to house and hold the energy emission. The next big obstacle to overcome dealt with converting the vast amounts of radiant energy into mechanical energy that would be used to compress the main body. In a report written by Yakov Borisovich Zel'dovich and Andrei Sakharov, it was stated that the new principle of atomic compression as seen in
15375-510: Was not only related to the hydrogen bomb, but also the nuclear industry as a whole. It provided detailed insight into the bomb design using a two-stage igniting block. The designs were quickly sent to Lavrentiy Beria , who had been placed in charge of the Russian bomb program by Joseph Stalin and forwarded to Igor Kurchatov , Boris Vannikov and Yulii Khariton, to validate and assess these designs. On May 5, 1948, Vannikov and Kurchatov wrote
15500-434: Was surrounded by layers of thermonuclear fuel and uranium. The entire system was to be compressed by an explosive placed all around the outside of the multi-layer sphere and initiate an implosion and ultimate initiation of the atomic initiator. The efficiency of this design earned Sakharov some prestige among his co-workers at Design Bureau 11. This design was referred to as the " Sloika " by Sakharov's co-workers as it resembled
15625-744: Was the Special Atomic Demolition Munition , or SADM, sometimes popularly known as a suitcase nuke . This is a nuclear bomb that is man-portable, or at least truck-portable, and though of a relatively small yield (one or two kilotons) is sufficient to destroy important tactical targets such as bridges, dams, tunnels, important military or commercial installations, etc. either behind enemy lines or pre-emptively on friendly territory soon to be overtaken by invading enemy forces. These weapons require plutonium fuel and are particularly "dirty". They also demand especially stringent security precautions in their storage and deployment. Small "tactical" nuclear weapons were deployed for use as antiaircraft weapons. Examples include
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