Nuclear shaped charges refers to nuclear weapons that focus the energy of their explosion into certain directions, as opposed to a spherical explosion. Edward Teller referred to such concepts as third-generation weapons, the first generation being the atom bomb and the second the H-bomb.
The basic concept has been raised on several occasions, with the first known references being part of the Project Orion nuclear-powered spacecraft project in the 1960s. This used beryllium oxide to convert the X-rays released by a small bomb into longer wavelength radiation, which explosively vaporized a tamper material, normally tungsten, causing it to carry away much of the bomb's energy as kinetic energy in the form of tungsten plasma. The same concept was explored as a weapon in the Casaba/Howitzer proposals.
The ideas were explored by Los Alamos National Laboratory as part of the Strategic Defense Initiative.
Project Orion in the 1960s envisioned the use of nuclear shaped charges for propulsion. The nuclear explosion would turn a tungsten plate into a jet of plasma that would then hit the drive pusher plate. About 85% of the bomb's energy could be directed into the target as plasma, albeit with a very wide cone angle of 22.5 degrees. A 4,000 ton spacecraft would use 5 kiloton charges, and a 10,000 ton spacecraft would use 15 kiloton charges. [1] Orion also researched the possibility of nuclear shaped charges being used as weapons in space warfare. These weapons would have yields of a few kilotons, could convert about 50% of that energy into a plasma jet with a velocity of 280 kilometers per second, and could theoretically get beam angles as low as 0.1 radians (5.73 degrees), quite wide but considerably narrower than the propulsion unit. [2]
The nuclear shaped charge concept was also studied extensively in the 1980s as part of Project Prometheus, along with bomb-pumped lasers. Using a combination of explosive wave-shaping and "gun-barrel" design, up to 5% of a small nuclear bomb could reportedly be converted into kinetic energy driving a beam of particles with a beam angle of 0.001 radians (0.057 degrees), far more concentrated than the earlier-proposed plasma jet, though this decreases to 1% efficiency at 50 kilotons (half a kiloton of energy in the beam) and efficiency suffers greatly at even higher yields. There has only been one known nuclear shaped charge test, conducted in 1985 as part of Operation Grenadier. During the test, codenamed 'Chamita', the intent was to use a nuclear detonation to accelerate a one kilogram mass of tungsten at one hundred kilometers per second, in the form of small particles focused in a cone-shaped beam. The test succeeded in propelling one kilogram of tungsten/molybdenum particles to seventy kilometers per second, about 0.59 tons of kinetic energy. [3] As the yield of the detonated nuclear device was 8 kilotons, [4] this came out to only 0.007% efficiency.
Princeton nuclear physicist Dan L. Fenstermacher stated that there is a fundamental problem associated with the Casaba Howitzer concept that becomes dire at higher yields: a good portion of the bomb's energy inevitably becomes black-body radiation, which would quickly overtake the propelled mass. This poses the risk that most of the particles will be vaporized or even ionized, rendering them useless for dealing damage to the target. He concluded: "The NKEW concept is thus one that may require subkiloton explosives to be feasible... Whatever the case may be, it is clear that demonstrating a rush of hypervelocity pellets from a nuclear blast, while perhaps impressive, in no way guarantees that a useful weapon will ever be derived from this concept." [5]
Little Boy was the name of the type of atomic bomb used in the bombing of the Japanese city of Hiroshima on 6 August 1945 during World War II, making it the first nuclear weapon used in warfare. The bomb was dropped by the Boeing B-29 Superfortress Enola Gay piloted by Colonel Paul W. Tibbets Jr., commander of the 509th Composite Group, and Captain Robert A. Lewis. It exploded with an energy of approximately 15 kilotons of TNT (63 TJ) and caused widespread death and destruction throughout the city. The Hiroshima bombing was the second nuclear explosion in history, after the Trinity nuclear test.
A shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Different types of shaped charges are used for various purposes such as cutting and forming metal, initiating nuclear weapons, penetrating armor, or perforating wells in the oil and gas industry.
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Theodore Brewster "Ted" Taylor was an American theoretical physicist, specifically concerning nuclear energy. His higher education included a PhD from Cornell University in theoretical physics. His most noteworthy contributions to the field of nuclear weaponry were his small bomb developments at the Los Alamos Laboratory in New Mexico. Although Taylor is not widely known to the general public, he is credited with numerous landmarks in fission nuclear weaponry development, including having developed the smallest, most powerful, and most efficient fission weapons ever tested by the US. Though Taylor was not considered a brilliant physicist from a calculative viewpoint, his vision and creativity allowed him to thrive in the field. The later part of Taylor's career was focused on nuclear energy instead of weaponry, and included his work on Project Orion, nuclear reactor developments, and anti-nuclear proliferation.
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A mushroom cloud is a distinctive mushroom-shaped flammagenitus cloud of debris, smoke, and usually condensed water vapor resulting from a large explosion. The effect is most commonly associated with a nuclear explosion, but any sufficiently energetic detonation or deflagration will produce the same effect. They can be caused by powerful conventional weapons, like thermobaric weapons such as the ATBIP and GBU-43/B MOAB. Some volcanic eruptions and impact events can produce natural mushroom clouds.
Project Orion was a study conducted in the 1950s and 1960s by the United States Air Force, DARPA, and NASA into the viability of a nuclear pulse spaceship that would be directly propelled by a series of atomic explosions behind the craft. Early versions of the vehicle were proposed to take off from the ground; later versions were presented for use only in space. The design effort took place at General Atomics in San Diego, and supporters included Wernher von Braun, who issued a white paper advocating the idea. Non-nuclear tests were conducted with models, but the project was eventually abandoned for several reasons, including the 1963 Partial Test Ban Treaty, which banned nuclear explosions in space, and concerns over nuclear fallout.
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A nuclear explosion is an explosion that occurs as a result of the rapid release of energy from a high-speed nuclear reaction. The driving reaction may be nuclear fission or nuclear fusion or a multi-stage cascading combination of the two, though to date all fusion-based weapons have used a fission device to initiate fusion, and a pure fusion weapon remains a hypothetical device. Nuclear explosions are used in nuclear weapons and nuclear testing.
An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated by a slower expansion that would normally not be forceful, but is not allowed to expand, so that when whatever is containing the expansion is broken by the pressure that builds as the matter inside tries to expand, the matter expands forcefully. An example of this is a volcanic eruption created by the expansion of magma in a magma chamber as it rises to the surface. Supersonic explosions created by high explosives are known as detonations and travel through shock waves. Subsonic explosions are created by low explosives through a slower combustion process known as deflagration.
Project Casaba-Howitzer was a 1960s-era study into the use of nuclear weapons as the drivers for intense beams of plasma for use in space warfare. The basic concept grew out of work on the Project Orion spaceship concept, which studied nuclear shaped charges.