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Bumpy Torus
The bumpy torus is a class of magnetic fusion energy devices that consist of a series of magnetic mirrors connected end-to-end to form a closed torus. It is based on a discovery made by a team headed by Dr. Ray Dandl at Oak Ridge National Laboratory in the 1960s. The main disadvantage of the classic magnetic mirror design is excessive plasma leakage through the two ends. The bumpy torus addresses this by connecting multiple mirrors together so fuel leaking from one mirror ends up in another. It is described as "bumpy" because the fuel ions comprising the plasma tend to concentrate inside the mirrors at a greater density than the leakage currents between mirror cells. An alternate description is that the magnetic field is narrower between the mirrors than in the center of each segment. Such an arrangement is not stable on its own, and most bumpy torus designs use secondary fields or relativistic electrons to create a stable field inside the reactor. Bumpy torus designs were an area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Fusion Energy
Magnetic confinement fusion is an approach to generate thermonuclear fusion power that uses magnetic fields to confine fusion fuel in the form of a plasma. Magnetic confinement is one of two major branches of fusion energy research, along with inertial confinement fusion. The magnetic approach began in the 1940s and absorbed the majority of subsequent development. Fusion reactions combine light atomic nuclei such as hydrogen to form heavier ones such as helium, producing energy. In order to overcome the electrostatic repulsion between the nuclei, they must have a temperature of tens of millions of degrees, creating a plasma. In addition, the plasma must be contained at a sufficient density for a sufficient time, as specified by the Lawson criterion (triple product). Magnetic confinement fusion attempts to use the electrical conductivity of the plasma to contain it through interaction with magnetic fields. The magnetic pressure offsets the plasma pressure. Developing a sui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Mirror
A magnetic mirror, known as a magnetic trap (магнитный захват) in Russia and briefly as a pyrotron in the US, is a type of magnetic confinement device used in fusion power to trap high temperature plasma using magnetic fields. The mirror was one of the earliest major approaches to fusion power, along with the stellarator and z-pinch machines. In a classic magnetic mirror, a configuration of electromagnets is used to create an area with an increasing density of magnetic field lines at either end of the confinement area. Particles approaching the ends experience an increasing force that eventually causes them to reverse direction and return to the confinement area. This mirror effect will only occur for particles within a limited range of velocities and angles of approach, those outside the limits will escape, making mirrors inherently "leaky". An analysis of early fusion devices by Edward Teller pointed out that the basic mirror concept is inherently unstable. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oak Ridge National Laboratory
Oak Ridge National Laboratory (ORNL) is a U.S. multiprogram science and technology national laboratory sponsored by the U.S. Department of Energy (DOE) and administered, managed, and operated by UT–Battelle as a federally funded research and development center (FFRDC) under a contract with the DOE, located in Oak Ridge, Tennessee. Established in 1943, ORNL is the largest science and energy national laboratory in the Department of Energy system (by size) and third largest by annual budget. It is located in the Roane County section of Oak Ridge, Tennessee. Its scientific programs focus on materials, nuclear science, neutron science, energy, high-performance computing, systems biology and national security, sometimes in partnership with the state of Tennessee, universities and other industries. ORNL has several of the world's top supercomputers, including Frontier, ranked by the TOP500 as the world's most powerful. The lab is a leading neutron and nuclear power re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solenoid
upright=1.20, An illustration of a solenoid upright=1.20, Magnetic field created by a seven-loop solenoid (cross-sectional view) described using field lines A solenoid () is a type of electromagnet formed by a helix, helical coil of wire whose length is substantially greater than its diameter, which generates a controlled magnetic field. The coil can produce a uniform magnetic field in a volume of space when an electric current is passed through it. The term ''solenoid'' was coined in 1823 by André-Marie Ampère. The helical coil of a solenoid does not necessarily need to revolve around a straight-line axis; for example, William Sturgeon's electromagnet of 1824 consisted of a solenoid bent into a horseshoe shape (not unlike an arc spring). Solenoids provide magnetic focusing of electrons in vacuums, notably in television camera tubes such as vidicons and image orthicons. Electrons take helical paths within the magnetic field. These solenoids, focus coils, surround nearly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. The electron's mass is approximately 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum ( spin) of a half-integer value, expressed in units of the reduced Planck constant, . Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: They can collide with other particles and can be diffracted like light. The wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Brog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Nucleus
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron in 1932, models for a nucleus composed of protons and neutrons were quickly developed by Dmitri Ivanenko and Werner Heisenberg. An atom is composed of a positively charged nucleus, with a cloud of negatively charged electrons surrounding it, bound together by electrostatic force. Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the electron cloud. Protons and neutrons are bound together to form a nucleus by the nuclear force. The diameter of the nucleus is in the range of () for hydrogen (the diameter of a single proton) to about for uranium. These dimensions are much smaller than the diameter of the atom itself (nucleus + electron cloud), by a factor of about 26,634 (uranium atomic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interchange Instability
The interchange instability is a type of plasma instability seen in magnetic fusion energy that is driven by the gradients in the magnetic pressure in areas where the confining magnetic field is curved. The name of the instability refers to the action of the plasma changing position with the magnetic field lines (i.e. an interchange of the lines of force in space) without significant disturbance to the geometry of the external field. The instability causes flute-like structures to appear on the surface of the plasma, and thus the instability is also known as the flute instability. The interchange instability is a key issue in the field of fusion energy, where magnetic fields are used to confine a plasma in a volume surrounded by the field. The basic concept was first noted in a 1954 paper by Martin David Kruskal and Martin Schwarzschild, which demonstrated that a situation similar to the Rayleigh–Taylor instability in classic fluids existed in magnetically confined plasmas. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resistive Ballooning Mode
The resistive ballooning mode (RBM) is an instability occurring in magnetized plasmas, particularly in magnetic confinement devices such as tokamaks, when the pressure gradient is opposite to the effective gravity created by a magnetic field. Linear growth rate The linear growth rate \gamma of the RBM instability is given as :\gamma^2 = -\vec\cdot\frac where , \nabla p, \sim \frac is the pressure gradient g_=c_s^2, \frac, \sim 1/R_0 is the effective gravity produced by a non-homogeneous magnetic field, ''R''0 is the major radius of the device, ''L''''p'' is a characteristic length of the pressure gradient, and ''c''''s'' is the plasma sound speed. Similarity with the Rayleigh–Taylor instability The RBM instability is similar to the Rayleigh–Taylor instability The Rayleigh–Taylor instability, or RT instability (after Lord Rayleigh and G. I. Taylor), is an instability of an interface between two fluids of different densities which occurs when the lighter fluid is pus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microwave
Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes both UHF and EHF ( millimeter wave) bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz (wavelengths between 0.3 m and 3 mm). In all cases, microwaves include the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations. The prefix ' in ''microwave'' is not meant to suggest a wavelength in the micrometer range. Rather, it indicates that microwaves are "small" (having shorter wavelengths), compared to the radio waves used prior to microwave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nagoya
is the largest city in the Chūbu region, the fourth-most populous city and third most populous urban area in Japan, with a population of 2.3million in 2020. Located on the Pacific coast in central Honshu, it is the capital and the most populous city of Aichi Prefecture, and is one of Japan's major ports along with those of Tokyo, Osaka, Kobe, Yokohama, and Chiba. It is the principal city of the Chūkyō metropolitan area, which is the third-most populous metropolitan area in Japan with a population of 10.11million in 2020. In 1610, the warlord Tokugawa Ieyasu, a retainer of Oda Nobunaga, moved the capital of Owari Province from Kiyosu to Nagoya. This period saw the renovation of Nagoya Castle. The arrival of the 20th century brought a convergence of economic factors that fueled rapid growth in Nagoya, during the Meiji Restoration, and became a major industrial hub for Japan. The traditional manufactures of timepieces, bicycles, and sewing machines were followed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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