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Ion Cyclotron Resonance
Ion cyclotron resonance is a phenomenon related to the movement of ions in a magnetic field. It is used for accelerating ions in a cyclotron, and for measuring the masses of an ionized analyte in mass spectrometry, particularly with Fourier transform ion cyclotron resonance mass spectrometers. It can also be used to follow the kinetics of chemical reactions in a dilute gas mixture, provided these involve charged species. Definition of the resonant frequency An ion in a static and uniform magnetic field will move in a circle due to the Lorentz force. The angular frequency of this ''cyclotron motion'' for a given magnetic field strength ''B'' is given by : \omega = 2\pi f = \frac, where ''z'' is the number of positive or negative charges of the ion, ''e'' is the elementary charge and ''m'' is the mass of the ion. An electric excitation signal having a frequency ''f'' will therefore resonate with ions having a mass-to-charge ratio ''m/z'' given by : \frac = \frac. The circular motion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ions
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons (e.g. K+ (potassium ion)) while an anion is a negatively charged ion with more electrons than protons (e.g. Cl− (chloride ion) and OH− (hydroxide ion)). Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed ''monatomic ions'', ''atomic ions'' or ''simple ions'', while ions consisting of two or more atoms are termed polyatomic ions or ''molecular ions''. If only a + or − is present, it indicates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma (physics)
Plasma () is a state of matter characterized by the presence of a significant portion of charged particles in any combination of ions or electrons. It is the most abundant form of ordinary matter in the universe, mostly in stars (including the Sun), but also dominating the rarefied intracluster medium and Outer space#Intergalactic space, intergalactic medium. Plasma can be artificially generated, for example, by heating a neutral gas or subjecting it to a strong electromagnetic field. The presence of charged particles makes plasma electrically conductive, with the dynamics of individual particles and macroscopic plasma motion governed by collective electromagnetic fields and very sensitive to externally applied fields. The response of plasma to electromagnetic fields is used in many modern devices and technologies, such as plasma display, plasma televisions or plasma etching. Depending on temperature and density, a certain number of neutral particles may also be present, in wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Source
An ion source is a device that creates atomic and molecular ions. Ion sources are used to form ions for mass spectrometers, optical emission spectrometers, particle accelerators, ion implanters and ion engines. Electron ionization Electron ionization is widely used in mass spectrometry, particularly for organic molecules. The gas phase reaction producing electron ionization is :M + e^- -> M^ + 2e^- where M is the atom or molecule being ionized, e^- is the electron, and M^ is the resulting ion. The electrons may be created by an arc discharge between a cathode and an anode. An electron beam ion source (EBIS) is used in atomic physics to produce highly charged ions by bombarding atoms with a powerful electron beam. Its principle of operation is shared by the electron beam ion trap. Electron capture ionization Electron capture ionization (ECI) is the ionization of a gas phase atom or molecule by attachment of an electron to create an ion of the form A−•. The r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric And Magnetic Fields In Matter
Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others. The presence of either a positive or negative electric charge produces an electric field. The motion of electric charges is an electric current and produces a magnetic field. In most applications, Coulomb's law determines the force acting on an electric charge. Electric potential is the work done to move an electric charge from one point to another within an electric field, typically measured in volts. Electricity plays a central role in many modern technologies, serving in electric power where electric current is used to energise equipment, and in electronics dealing with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condensed Matter Physics
Condensed matter physics is the field of physics that deals with the macroscopic and microscopic physical properties of matter, especially the solid and liquid State of matter, phases, that arise from electromagnetic forces between atoms and electrons. More generally, the subject deals with condensed phases of matter: systems of many constituents with strong interactions among them. More exotic condensed phases include the superconductivity, superconducting phase exhibited by certain materials at extremely low cryogenic temperatures, the ferromagnetic and antiferromagnetic phases of Spin (physics), spins on crystal lattices of atoms, the Bose–Einstein condensates found in ultracold atomic systems, and liquid crystals. Condensed matter physicists seek to understand the behavior of these phases by experiments to measure various material properties, and by applying the physical laws of quantum mechanics, electromagnetism, statistical mechanics, and other theoretical physics, physic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclotron Resonance (other) - the motions of electrons in a magnetic field
{{disambiguation ...
Cyclotron resonance may refer to: * Cyclotron motion - the motion of charged particles in a magnetic field * Ion cyclotron resonance - the motion of heavy ions in a magnetic field * Electron cyclotron resonance Electron cyclotron resonance (ECR) is a phenomenon observed in plasma physics, condensed matter physics, and accelerator physics. It happens when the frequency of incident radiation coincides with the natural frequency of rotation of electrons in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutral-beam Injection
Neutral-beam injection (NBI) is one method used to heat plasma inside a fusion device consisting in a beam of high-energy neutral particles that can enter the magnetic confinement field. When these neutral particles are ionized by collision with the plasma particles, they are kept in the plasma by the confining magnetic field and can transfer most of their energy by further collisions with the plasma. By tangential injection in the torus, neutral beams also provide momentum to the plasma and current drive, one essential feature for long pulses of burning plasmas. Neutral-beam injection is a flexible and reliable technique, which has been the main heating system on a large variety of fusion devices. To date, all NBI systems were based on positive precursor ion beams. In the 1990s there has been impressive progress in negative ion sources and accelerators with the construction of multi-megawatt negative-ion-based NBI systems at LHD (H0, 180 keV) and JT-60U (D0, 500 keV). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Cyclotron Resonance
Electron cyclotron resonance (ECR) is a phenomenon observed in plasma physics, condensed matter physics, and accelerator physics. It happens when the frequency of incident radiation coincides with the natural frequency of rotation of electrons in magnetic fields. A free electron in a static and uniform magnetic field will move in a circle due to the Lorentz force. The circular motion may be superimposed with a uniform axial motion, resulting in a helix, or with a uniform motion perpendicular to the field (e.g., in the presence of an electrical or gravitational field) resulting in a cycloid. The angular frequency (''ω'' = 2''π'' ''f'' ) of this '' cyclotron motion'' for a given magnetic field strength ''B'' is given (in SI units) by : \omega_\text = \frac. where e is the elementary charge and m_\text is the mass of the electron. For the commonly used microwave frequency 2.45 GHz and the bare electron charge and mass, the resonance condition is met when ''B'' = . F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Wave
Radio waves (formerly called Hertzian waves) are a type of electromagnetic radiation with the lowest frequencies and the longest wavelengths in the electromagnetic spectrum, typically with frequencies below 300 gigahertz (GHz) and wavelengths greater than , about the diameter of a grain of rice. Radio waves with frequencies above about 1 GHz and wavelengths shorter than 30 centimeters are called microwaves. Like all electromagnetic waves, radio waves in vacuum travel at the speed of light, and in the Earth's atmosphere at a slightly lower speed. Radio waves are generated by charged particles undergoing acceleration, such as time-varying electric currents. Naturally occurring radio waves are emitted by lightning and astronomical radio source, astronomical objects, and are part of the blackbody radiation emitted by all warm objects. Radio waves are generated artificially by an electronic device called a transmitter, which is connected to an antenna (radio), antenna, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellarator
A stellarator confines Plasma (physics), plasma using external magnets. Scientists aim to use stellarators to generate fusion power. It is one of many types of magnetic confinement fusion devices. The name "stellarator" refers to stars because fusion mostly occurs in stars such as the Sun. It is one of the earliest human-designed fusion power devices. The stellarator was invented by American scientist Lyman Spitzer in 1951. Much of its early development was carried out by Spitzer's team at what became the Princeton Plasma Physics Laboratory (PPPL). Spitzer's Model A began operation in 1953 and demonstrated plasma confinement. Larger models followed, but demonstrated poor performance, losing plasma at rates far worse than theoretical predictions. By the early 1960s, hopes of producing a commercial machine faded, and attention turned to studying fundamental theory. By the mid-1960s, Spitzer was convinced that the stellarator was matching the Bohm diffusion rate, which suggested i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Confinement Fusion
Magnetic confinement fusion (MCF) is an approach to generate thermonuclear fusion power that uses magnetic fields to confine fusion fuel in the form of a plasma (physics), plasma. Magnetic confinement is one of two major branches of controlled fusion research, along with inertial confinement fusion. Deuterium–tritium fusion, Fusion reactions for reactors usually combine light Atomic nucleus, atomic nuclei of deuterium and tritium to form an alpha particle (helium-4 nucleus) and a neutron, where the energy is released in the form of the kinetic energy of the reaction products. In order to overcome the Coulomb barrier, electrostatic repulsion between the nuclei, the fuel must have a temperature of hundreds of millions of kelvin, at which the fuel is fully Ionization, ionized and becomes a Plasma (physics), plasma. In addition, the plasma must be at a sufficient density, and the energy must remain in the reacting region for a sufficient time, as specified by the Lawson criterion (tri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Wind
The solar wind is a stream of charged particles released from the Sun's outermost atmospheric layer, the Stellar corona, corona. This Plasma (physics), plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the solar wind plasma also includes a mixture of particle species found in the solar plasma: trace amounts of heavy ions and atomic nuclei of Chemical element, elements such as carbon, nitrogen, oxygen, neon, magnesium, silicon, sulfur, and iron. There are also rarer traces of some other nuclei and isotopes such as phosphorus, titanium, chromium, and nickel's isotopes 58Ni, 60Ni, and 62Ni. Superimposed with the solar-wind plasma is the interplanetary magnetic field. The solar wind varies in density, temperature and speed over time and over Solar coordinate systems#Heliographic, solar latitude and longitude. Its particles can escape the Sun's gravity because of their high energy resulting from the high temperature of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
