|
Mie Scattering
In electromagnetism, the Mie solution to Maxwell's equations (also known as the Lorenz–Mie solution, the Lorenz–Mie–Debye solution or Mie scattering) describes the scattering of an electromagnetic plane wave by a homogeneous sphere. The solution takes the form of an infinite series of spherical multipole partial waves. It is named after German physicist Gustav Mie. The term ''Mie solution'' is also used for solutions of Maxwell's equations for scattering by stratified spheres or by infinite cylinders, or other geometries where one can write separate equations for the radial and angular dependence of solutions. The term ''Mie theory'' is sometimes used for this collection of solutions and methods; it does not refer to an independent physical theory or law. More broadly, the "Mie scattering" formulas are most useful in situations where the size of the scattering particles is comparable to the wavelength of the light, rather than much smaller or much larger. Mie scattering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Cross Section
Radar cross-section (RCS), denoted σ, also called radar signature, is a measure of how detectable an object is by radar. A larger RCS indicates that an object is more easily detected. An object reflects a limited amount of radar energy back to the source. The factors that influence this include: *the material with which the target is made; *the size of the target relative to the wavelength of the illuminating radar signal; *the absolute size of the target; *the incident angle (angle at which the radar beam hits a particular portion of the target, which depends upon the shape of the target and its orientation to the radar source); *the reflected angle (angle at which the reflected beam leaves the part of the target hit; it depends upon incident angle); *the polarization of the radiation transmitted and received with respect to the orientation of the target. While important in detecting targets, strength of emitter and distance are not factors that affect the calculation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vector Spherical Harmonics
In mathematics, vector spherical harmonics (VSH) are an extension of the scalar spherical harmonics for use with vector fields. The components of the VSH are complex-valued functions expressed in the spherical coordinate basis vectors. Definition Several conventions have been used to define the VSH. We follow that of Barrera ''et al.''. Given a scalar spherical harmonic , we define three VSH: * \mathbf_ = Y_\hat, * \mathbf_ = r\nabla Y_, * \mathbf_ = \mathbf\times\nabla Y_, with \hat being the unit vector along the radial direction in spherical coordinates and \mathbf the vector along the radial direction with the same norm as the radius, i.e., \mathbf = r\hat. The radial factors are included to guarantee that the dimensions of the VSH are the same as those of the ordinary spherical harmonics and that the VSH do not depend on the radial spherical coordinate. The interest of these new vector fields is to separate the radial dependence from the angular one when using spherical c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hendrik C
{{disambig, surname ...
Hendrik may refer to: People * Hendrik (given name) * Hans Hendrik (1832–1889), Greenlandic Arctic traveller and interpreter * Tony Hendrik (born 1945), German music producer and composer Others * Hendrik Island, an island in Greenland * Hendrik-Ido-Ambacht, a municipality in the Netherlands * A character from ''Dragon Quest XI'' See also * Hendrich (other) * Hendrick (other) * Henrich Henrich is both a surname and a given name. Notable people with the name include: Surname * Adam Henrich (born 1984), Canadian former ice hockey player * Allison Henrich (born 1980), American mathematician * Bernhard Henrich, set decorator * Bob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rayleigh–Gans Approximation
Rayleigh–Gans approximation, also known as Rayleigh–Gans–Debye approximation and Rayleigh–Gans–Born approximation, is an approximate solution to light scattering by particles, light scattering by optically soft particles. Optical softness implies that the relative refractive index of particle is close to that of the surrounding medium. The approximation holds for particles of arbitrary shape that are relatively small but can be larger than Rayleigh scattering limits. The theory was derived by John William Strutt, 3rd Baron Rayleigh, Lord Rayleigh in 1881 and was applied to homogeneous spheres, spherical shells, radially inhomogeneous spheres and infinite cylinders. Peter Debye has contributed to the theory in 1881. The theory for homogeneous sphere was rederived by Richard Gans in 1925. The approximation is analogous to Born approximation in quantum mechanics. Theory The validity conditions for the approximation can be denoted as: :, n-1, \ll 1 :kd, n-1, \ll 1 k is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractive Index
In optics, the refractive index (or refraction index) of an optical medium is the ratio of the apparent speed of light in the air or vacuum to the speed in the medium. The refractive index determines how much the path of light is bent, or refraction, refracted, when entering a material. This is described by Snell's law of refraction, , where and are the angle of incidence (optics), angle of incidence and angle of refraction, respectively, of a ray crossing the interface between two media with refractive indices and . The refractive indices also determine the amount of light that is reflectivity, reflected when reaching the interface, as well as the critical angle for total internal reflection, their intensity (Fresnel equations) and Brewster's angle. The refractive index, n, can be seen as the factor by which the speed and the wavelength of the radiation are reduced with respect to their vacuum values: the speed of light in a medium is , and similarly the wavelength in that me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Debye
Peter Joseph William Debye ( ; born Petrus Josephus Wilhelmus Debije, ; March 24, 1884 – November 2, 1966) was a Dutch-American physicist and physical chemist, and Nobel laureate in Chemistry. Biography Early life Born in Maastricht, Netherlands, Debye enrolled in the Aachen University of Technology in 1901. In 1905, he completed his first degree in electrical engineering. He published his first paper, a mathematically elegant solution of a problem involving eddy currents, in 1907. At Aachen, he studied under the theoretical physicist Arnold Sommerfeld, who later claimed that his most important discovery was Peter Debye. In 1906, Sommerfeld received an appointment at Munich, Bavaria, and took Debye with him as his assistant. Debye got his Ph.D. with a dissertation on radiation pressure in 1908. In 1910, he derived the Planck radiation formula using a method which Max Planck agreed was simpler than his own. In 1911, when Albert Einstein took an appointment as a profes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Gans
__NOTOC__ Richard Martin Gans (7 March 1880 – 27 June 1954), German of Jewish origin, born in Hamburg, was the physicist who founded the Physics Institute of the National University of La Plata, Argentina. He was its Director in two different periods. During the first one, starting in 1911, he continued the work started by Emil Bose raising the research level of the institute to international renown. In 1914 he founded the publication of a scientific journal: ''Contribución al estudio de las ciencias fisicomatemáticas,'' with two series: ''matematicofísica'' and ''técnica.'' His second period in La Plata was from the late 1940s through the early 1950s, when he played an important role as member of one of the commissions which reviewed Ronald Richter's claims related to the Huemul Project. After leaving La Plata in 1951 he taught theoretical and advanced physics at the University of Buenos Aires. Gans theory is named after Richard Gans. This theory gives the solution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lord Rayleigh
John William Strutt, 3rd Baron Rayleigh ( ; 12 November 1842 – 30 June 1919), was an English physicist who received the Nobel Prize in Physics in 1904 "for his investigations of the densities of the most important gases and for his discovery of argon in connection with these studies". He served as president of the Royal Society from 1905 to 1908 and as chancellor of the University of Cambridge from 1908 to 1919. Rayleigh provided the first theoretical treatment of the elastic scattering of light by particles much smaller than the light's wavelength, a phenomenon now known as "Rayleigh scattering", which notably explains why the sky is blue. He studied and described transverse surface waves in solids, now known as "Rayleigh waves". He contributed extensively to fluid dynamics, with concepts such as the Rayleigh number (a dimensionless number associated with natural convection), Rayleigh flow, the Rayleigh–Taylor instability, and Rayleigh's criterion for the stability of Ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Cross Section
Optical cross section (OCS) is a value which describes the maximum amount of optical flux reflected back to the source. The standard unit of measurement is m2/sr. OCS is dependent on the geometry and the reflectivity at a particular wavelength of an object. Optical cross section is useful in fields such as LIDAR. In the field of radar this is referred to as radar cross-section. Objects such as license plates on automobiles have a high optical cross section to maximize the laser return to the speed detector gun. Flat mirror Optical cross section of a flat mirror with a given reflectivity at a particular wavelength r(\lambda) can be expressed by the formula : \mbox=r(\lambda) \frac Where D is the cross sectional diameter of the beam. Note that the direction of the light has to be perpendicular to the mirror surface for this formula to be valid, else the return from the mirror would no longer go back to it source. In order to maximize the return a corner reflector is used. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
