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Biconic Cusp
The biconic cusp was one of the earliest suggestions for plasma confinement in a fusion reactor. It consists of two parallel electromagnets with the current running in opposite directions, creating oppositely directed magnetic fields. The two fields interact to form a "null area" between them where the fusion fuel can be trapped. Most early work on the cusp design was carried out at the Courant Institute in New York by Harold Grad in the late 1950s and early 1960s. Variations on the basic concept include the picket fence reactor built at Los Alamos in the 1950s and ring reactors. All of these devices leaked their fuel plasma at rates much greater than predicted and most work on the concept ended by the mid-1960s. Mikhail Ioffe later demonstrated why these problems arose. A later device that shares some design with the cusp is the polywell concept of the 1990s. This can be thought of as multiple cusps arranged in three dimensions. Description The magnetic fields in this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biconic Cusp
The biconic cusp was one of the earliest suggestions for plasma confinement in a fusion reactor. It consists of two parallel electromagnets with the current running in opposite directions, creating oppositely directed magnetic fields. The two fields interact to form a "null area" between them where the fusion fuel can be trapped. Most early work on the cusp design was carried out at the Courant Institute in New York by Harold Grad in the late 1950s and early 1960s. Variations on the basic concept include the picket fence reactor built at Los Alamos in the 1950s and ring reactors. All of these devices leaked their fuel plasma at rates much greater than predicted and most work on the concept ended by the mid-1960s. Mikhail Ioffe later demonstrated why these problems arose. A later device that shares some design with the cusp is the polywell concept of the 1990s. This can be thought of as multiple cusps arranged in three dimensions. Description The magnetic fields in this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polywell
The polywell is a proposed design for a fusion reactor using an electric field to heat ions to fusion conditions. The design is related to the fusor, the high beta fusion reactor, the magnetic mirror, and the biconic cusp. A set of electromagnets generates a magnetic field that traps electrons. This creates a negative voltage, which attracts positive ions. As the ions accelerate towards the negative center, their kinetic energy rises. Ions that collide at high enough energies can fuse. Mechanism Fusor A Farnsworth-Hirsch fusor consists of two wire cages, one inside the other, often referred to as grids, that are placed inside a vacuum chamber. The outer cage has a positive voltage versus the inner cage. A fuel, typically, deuterium gas, is injected into this chamber. It is heated past its ionization temperature, making positive ions. The ions are positive and move towards the negative inner cage. Those that miss the wires of the inner cage fly through the center of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polywell
The polywell is a proposed design for a fusion reactor using an electric field to heat ions to fusion conditions. The design is related to the fusor, the high beta fusion reactor, the magnetic mirror, and the biconic cusp. A set of electromagnets generates a magnetic field that traps electrons. This creates a negative voltage, which attracts positive ions. As the ions accelerate towards the negative center, their kinetic energy rises. Ions that collide at high enough energies can fuse. Mechanism Fusor A Farnsworth-Hirsch fusor consists of two wire cages, one inside the other, often referred to as grids, that are placed inside a vacuum chamber. The outer cage has a positive voltage versus the inner cage. A fuel, typically, deuterium gas, is injected into this chamber. It is heated past its ionization temperature, making positive ions. The ions are positive and move towards the negative inner cage. Those that miss the wires of the inner cage fly through the center of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gyroradius
The gyroradius (also known as radius of gyration, Larmor radius or cyclotron radius) is the radius of the circular motion of a charged particle in the presence of a uniform magnetic field. In SI units, the non-relativistic gyroradius is given by :r_ = \frac where m is the mass of the particle, v_ is the component of the velocity perpendicular to the direction of the magnetic field, q is the electric charge of the particle, and B is the strength of the magnetic field. The angular frequency of this circular motion is known as the gyrofrequency, or cyclotron frequency, and can be expressed as :\omega_ = \frac in units of radians/second. Variants It is often useful to give the gyrofrequency a sign with the definition :\omega_ = \frac or express it in units of hertz with :f_ = \frac. For electrons, this frequency can be reduced to :f_ = (2.8\times10^\,\mathrm/\mathrm)\times B. In cgs-units the gyroradius :r_ = \frac and the corresponding gyrofrequency :\omega_ = \frac include a factor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larmor Formula
In electrodynamics, the Larmor formula is used to calculate the total power radiated by a nonrelativistic point charge as it accelerates. It was first derived by J. J. Larmor in 1897, in the context of the wave theory of light. When any charged particle (such as an electron, a proton, or an ion) accelerates, energy is radiated in the form of electromagnetic waves. For a particle whose velocity is small relative to the speed of light (i.e., nonrelativistic), the total power that the particle radiates (when considered as a point charge) can be calculated by the Larmor formula: P = \frac \left(\frac\right)^2 = \frac= \frac = \mu_0 \frac \text P = \frac \text where \dot v or a — is the proper acceleration, q — is the charge, and c — is the speed of light. A relativistic generalization is given by the Liénard–Wiechert potentials. In either unit system, the power radiated by a single electron can be expressed in terms of the classical electron radius and elect ... [...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] |
Null (physics)
In physics a null is a point in a field where the field quantity is zero as the result of two or more opposing quantities completely cancelling each other. The field may be scalar, vector or tensor in nature. Common situations where nulls arise are in the polar patterns of microphones and antennae, and nulls caused by reflections of waves. Microphones A common polar pattern for microphones is the cardioid. This has a single direction in which the microphone does not respond to impinging sound waves. Highly directional (shotgun) microphones have more complex polar patterns. These microphones have a large, narrow lobe in the main direction of sound reception but also a smaller lobe in the opposite direction and usually also several other smaller lobes. This pattern is achieved by wave cancellation inside the body of the microphone. Between each of these lobes is a null direction where no sound at all is detected. Antennae {{main, null (radio) A common, and basic, radio a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Null (physics)
In physics a null is a point in a field where the field quantity is zero as the result of two or more opposing quantities completely cancelling each other. The field may be scalar, vector or tensor in nature. Common situations where nulls arise are in the polar patterns of microphones and antennae, and nulls caused by reflections of waves. Microphones A common polar pattern for microphones is the cardioid. This has a single direction in which the microphone does not respond to impinging sound waves. Highly directional (shotgun) microphones have more complex polar patterns. These microphones have a large, narrow lobe in the main direction of sound reception but also a smaller lobe in the opposite direction and usually also several other smaller lobes. This pattern is achieved by wave cancellation inside the body of the microphone. Between each of these lobes is a null direction where no sound at all is detected. Antennae {{main, null (radio) A common, and basic, radio a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma (physics)
Plasma ()πλάσμα , Henry George Liddell, Robert Scott, ''A Greek English Lexicon'', on Perseus is one of the four fundamental states of matter. It contains a significant portion of charged particles – ions and/or s. The presence of these charged particles is what primarily sets plasma apart from the other fundamental states of matter. It is the most abundant form of ordi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnets
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a coil. A current through the wire creates a magnetic field which is concentrated in the hole in the center of the coil. The magnetic field disappears when the current is turned off. The wire turns are often wound around a magnetic core made from a ferromagnetic or ferrimagnetic material such as iron; the magnetic core concentrates the magnetic flux and makes a more powerful magnet. The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be quickly changed by controlling the amount of electric current in the winding. However, unlike a permanent magnet that needs no power, an electromagnet requires a continuous supply of current to maintain the magnetic field. Electromagnets are widely used as components of other electrical devices, such as motors, generators, electromechanical so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mikhail Ioffe
Mikhail Solomonovich Ioffe (russian: Михаил Соломонович Иоффе; 2 September 191714 July 1996) was a Soviet physicist best known for his work on magnetic mirror fusion devices, and especially his 1961 experimental device that demonstrated gross plasma stability was possible in a properly arranged magnetic field. His concept is known today as "". Viewed with disfavour by the Soviet establishment for his cordial ties with his counterparts in the west, he was forbidden from leaving the Soviet Union until the dissolution of the Soviet Union. He subsequently received numerous international awards. Life Ioffe was born on 2 September 1917 in Samara. He studied physics at Leningrad University and graduated in 1940 with a diploma, roughly similar to a master's degree. He served in the Red Army from 1941 to 1946. On leaving the Army, Ioffe became a staff member of the Physico-Technical Institute of Leningrad. In 1948 he moved to the Kurchatov Institute in Moscow, at tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Confinement
In plasma physics, plasma confinement refers to the act of maintaining a plasma in a discrete volume. Confining plasma is required in order to achieve fusion power. There are two major approaches to confinement: magnetic confinement 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 ... and inertial confinement. See also * List of plasma (physics) articles References Plasma physics {{plasma-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
