Like our own sun, Betelgeuse transfers its thermonuclear energy by convection from the center, where it is generated, to its surface.
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Production of progressively heavier synthetic elements continued into 21st century as a branch of nuclear physics, but only for scientific purposes. The third important stream in nuclear physics are researches related to nuclear fusion. This is related to thermonuclear weapons (and conceived peaceful thermonuclear energy), as well as to astrophysical researches, such as stellar nucleosynthesis and Big Bang nucleosynthesis.
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Flames do not need to be driven only by chemical energy release. In stars, subsonic burning fronts driven by burning light nuclei (like carbon or helium) to heavy nuclei (up to iron group) propagate as flames. This is important in some models of Type Ia supernovae. In thermonuclear flames, thermal conduction dominates over species diffusion, so the flame speed and thickness is determined by the thermonuclear energy release and thermal conductivity (often in the form of degenerate electrons).
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A 40 MW demonstration unit at the Peach Bottom Nuclear Generating Station in Pennsylvania operated successfully, but a larger 300 MW unit at the Fort St. Vrain Generating Station in Colorado encountered technical problems. General Atomics also conducted research into thermonuclear energy, including means of magnetically confining plasma. Between 1962 and 1974 Creutz published six papers on the subject. In 1970 President Richard Nixon appointed Creutz as Assistant Director for Research of the National Science Foundation.
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This was a particularly remarkable development since at that time fusion and thermonuclear energy, and even that stars are largely composed of hydrogen (see metallicity), had not yet been discovered. In 1925 Cecilia Helena Payne (later Cecilia Payne-Gaposchkin) wrote an influential doctoral dissertation at Radcliffe College, in which she applied ionization theory to stellar atmospheres to relate the spectral classes to the temperature of stars. Most significantly, she discovered that hydrogen and helium were the principal components of stars. Despite Eddington's suggestion, this discovery was so unexpected that her dissertation readers convinced her to modify the conclusion before publication.
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This was a particularly remarkable development since at that time fusion and thermonuclear energy had not yet been discovered, nor even that stars are largely composed of hydrogen (see metallicity). Eddington's paper reasoned that: # The leading theory of stellar energy, the contraction hypothesis, should cause stars' rotation to visibly speed up due to conservation of angular momentum. But observations of Cepheid variable stars showed this was not happening. # The only other known plausible source of energy was conversion of matter to energy; Einstein had shown some years earlier that a small amount of matter was equivalent to a large amount of energy.
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At that time, the source of stellar energy was a complete mystery; Eddington correctly speculated that the source was fusion of hydrogen into helium, liberating enormous energy according to Einstein's equation . This was a particularly remarkable development since at that time fusion and thermonuclear energy, and even the fact that stars are largely composed of hydrogen (see metallicity), had not yet been discovered. Eddington's paper, based on knowledge at the time, reasoned that: :# The leading theory of stellar energy, the contraction hypothesis, should cause stars' rotation to visibly speed up due to conservation of angular momentum. But observations of Cepheid variable stars showed this was not happening.
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This was a particularly remarkable development since at that time fusion and thermonuclear energy, and even that stars are largely composed of hydrogen (see metallicity), had not yet been discovered. The Rutherford model worked quite well until studies of nuclear spin were carried out by Franco Rasetti at the California Institute of Technology in 1929. By 1925 it was known that protons and electrons each had a spin of . In the Rutherford model of nitrogen-14, 20 of the total 21 nuclear particles should have paired up to cancel each other's spin, and the final odd particle should have left the nucleus with a net spin of .
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From 1957 to 1962 Kerst was employed at the General Atomics division of General Dynamics's John Jay Hopkins Laboratory for Pure and Applied Science in La Jolla, California, where he worked on plasma physics, which it was hoped was the doorway to the control of thermonuclear energy. With Tihiro Ohkawa he invented toroidal devices for containing the plasma with magnetic fields. The two completed this work at the University of Wisconsin, where Kerst was a professor from 1962 until his retirement in 1980. Their devices were the first to contain plasma without the instabilities that had plagued previous designs, and the first to contain plasma for lifetimes exceeding the Bohm diffusion limit.
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Following Russell's presentation of the diagram to a meeting of the Royal Astronomical Society in 1912, Arthur Eddington was inspired to use it as a basis for developing ideas on stellar physics. In 1926, in his book The Internal Constitution of the Stars he explained the physics of how stars fit on the diagram. The paper anticipated the later discovery of nuclear fusion and correctly proposed that the star's source of power was the combination of hydrogen into helium, liberating enormous energy. This was a particularly remarkable intuitive leap, since at that time the source of a star's energy was still unknown, thermonuclear energy had not been proven to exist, and even that stars are largely composed of hydrogen (see metallicity), had not yet been discovered.
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