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Plasma Receiver
A plasma wave instrument (PWI), also known as a plasma wave receiver, is a device capable of detecting vibrations in outer space plasma and transforming them into audible sound waves or air vibrations that can be heard by the human ear. This instrument was pioneered by then-University of Iowa physics professor, Donald Gurnett. Plasma wave instruments are commonly employed on space probes such as GEOTAIL, Polar, Voyager I and II (see Plasma Wave Subsystem), and Cassini–Huygens. Operating principle Vibrations in the audible frequency range are perceived by humans when air vibrates against their eardrum. Air, or some other vibrating medium such as water, is essential for sound perception by the human ear. Without a medium to transmit it, the sound produced by a source will not be heard by a human. There is no air in outer space, nor is there any other type of medium capable of transmitting vibrations from a source to a human ear. However, there are sources in outer space that vib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma (physics)
Plasma () 1, where \nu_ is the electron gyrofrequency and \nu_ is the electron collision rate. It is often the case that the electrons are magnetized while the ions are not. Magnetized plasmas are ''anisotropic'', meaning that their properties in the direction parallel to the magnetic field are different from those perpendicular to it. While electric fields in plasmas are usually small due to the plasma high conductivity, the electric field associated with a plasma moving with velocity \mathbf in the magnetic field \mathbf is given by the usual Lorentz force, Lorentz formula \mathbf = -\mathbf\times\mathbf, and is not affected by Debye shielding. Mathematical descriptions To completely describe the state of a plasma, all of the particle locations and velocities that describe the electromagnetic field in the plasma region would need to be written down. However, it is generally not practical or necessary to keep track of all the particles in a plasma. Therefore, plasma physicist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Wind
The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This 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 materials found in the solar plasma: trace amounts of heavy ions and atomic nuclei such as C, N, O, Ne, Mg, Si, S, and Fe. There are also rarer traces of some other nuclei and isotopes such as P, Ti, Cr, 54Fe and 56Fe, and 58Ni, 60Ni, and 62Ni. Superposed with the solar-wind plasma is the interplanetary magnetic field. The solar wind varies in density, temperature and speed over time and over solar latitude and longitude. Its particles can escape the Sun's gravity because of their high energy resulting from the high temperature of the corona, which in turn is a result of the coronal magnetic field. The boundary separating the corona from the solar wind is called the Alfvén surface. At a distance of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Diagnostics
Plasma diagnostics are a pool of methods, instruments, and experimental techniques used to measure properties of a Plasma (physics), plasma, such as plasma components' density, distribution function over energy (temperature), their spatial profiles and dynamics, which enable to derive plasma parameters. Invasive probe methods Ball-pen probe A ball-pen probe is novel technique used to measure directly the plasma potential in magnetized plasmas. The probe was invented by Jiřà Adámek in the Institute of Plasma Physics AS CR in 2004. The ball-pen probe balances the electron saturation current to the same magnitude as that of the ion saturation current. In this case, its Langmuir probe, floating potential becomes identical to the plasma potential. This goal is attained by a ceramic shield, which screens off an adjustable part of the electron current from the probe collector due to the much smaller gyro–radius of the electrons. The electron temperature is proportional to the differen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Providence, Rhode Island
Providence is the capital and most populous city of the U.S. state of Rhode Island. One of the oldest cities in New England, it was founded in 1636 by Roger Williams, a Reformed Baptist theologian and religious exile from the Massachusetts Bay Colony. He named the area in honor of "God's merciful Providence" which he believed was responsible for revealing such a haven for him and his followers. The city developed as a busy port as it is situated at the mouth of the Providence River in Providence County, at the head of Narragansett Bay. Providence was one of the first cities in the country to industrialize and became noted for its textile manufacturing and subsequent machine tool, jewelry, and silverware industries. Today, the city of Providence is home to eight hospitals and List of colleges and universities in Rhode Island#Institutions, eight institutions of higher learning which have shifted the city's economy into service industries, though it still retains some manufacturin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
String Quartet
The term string quartet can refer to either a type of musical composition or a group of four people who play them. Many composers from the mid-18th century onwards wrote string quartets. The associated musical ensemble consists of two violinists, a violist, and a cellist. The string quartet was developed into its present form by composers such as Franz Xaver Richter, and Joseph Haydn, whose works in the 1750s established the ensemble as a group of four more-or-less equal partners. Since Haydn the string quartet has been considered a prestigious form; writing for four instruments with broadly similar characteristics both constrains and tests a composer. String quartet composition flourished in the Classical era, and Wolfgang Amadeus Mozart, Ludwig van Beethoven and Franz Schubert each wrote a number of them. Many Romantic and early-twentieth-century composers composed string quartets, including Felix Mendelssohn, Robert Schumann, Johannes Brahms, AntonÃn Dvořák, LeoÅ¡ Janà ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sun Rings
''Sun Rings'' is a Kronos Quartet project comprising pre-recorded sounds from space, images from space, music for string quartet and chorus composed by Terry Riley, and visuals by Willie Williams. It premiered 26 October 2002 at the Hancher Auditorium, University of Iowa. The project started in 2000 when the NASA Art Program The NASA Art Program was established in 1962. NASA administrator, James Webb, jump-started the program by recommending artists to become involved in the agency. Artists, including Norman Rockwell, Robert Rauschenberg, and Andy Warhol were commissio ... invited the Kronos Quartet to incorporate sounds, recorded over a period of 40 years by plasma wave receivers on board spacecraft, into music. References External links Sun Ringsat Kronos Quartet website Space Audio Compositions by Terry Riley Compositions for string quartet 2002 compositions Commissioned music Kronos Quartet albums {{chamber-composition-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Harrington (musician)
The Kronos Quartet is an American string quartet based in San Francisco. It has been in existence with a rotating membership of musicians for almost 50 years. The quartet covers a very broad range of musical genres, including contemporary classical music. More than 900 works have been written for it. History The quartet was founded by violinist David Harrington in Seattle, Washington. Its first performance was in November 1973. Since 1978, the quartet has been based in San Francisco, California. The longest-running combination of performers (from 1978 to 1999) had Harrington and John Sherba on violin, Hank Dutt on viola, and Joan Jeanrenaud on cello. In 1999, Jeanrenaud left Kronos because she was "eager for something new"; she was replaced by Jennifer Culp, who, in turn, left in 2005 and was replaced by Jeffrey Zeigler. In June 2013, Zeigler was replaced by Sunny Yang. With over 40 studio albums to their credit and having performed worldwide, they have been called "probably the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terry Riley
Terrence Mitchell "Terry" Riley (born June 24, 1935) is an American composer and performing musician best known as a pioneer of the minimalist school of composition. Influenced by jazz and Indian classical music, his music became notable for its innovative use of repetition, tape music techniques, and delay systems. His best known works are the 1964 composition '' In C'' and the 1969 LP ''A Rainbow in Curved Air'', both considered landmarks of minimalism and important influences on experimental music, rock, and contemporary electronic music. Raised in California, Riley began studying composition and performing solo piano in the 1950s. He befriended and collaborated with composer La Monte Young, and later became involved with the San Francisco Tape Music Center. A three-record deal with CBS in the late 1960s, resulting in an LP recording of ''In C'' (1968) and ''A Rainbow in Curved Air'' (1969), brought his work to wider audiences. In 1970, he began intensive studies under Hin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew spacecraft, and the planned Lunar Gateway space station. The agency is also responsible for the Launch Services Program, which provides oversight of launch operations and countdown management f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescent Lamp
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow. A fluorescent lamp converts electrical energy into useful light much more efficiently than an incandescent lamp. The typical luminous efficacy of fluorescent lighting systems is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output. For comparison, the luminous efficacy of an incandescent bulb may only be 16 lumens per watt. Fluorescent lamp fixtures are more costly than incandescent lamps because, among other things, they require a ballast to regulate current through the lamp, but the initial cost is offset by a much lower running cost. Compact fluorescent lamps are now available in the same popular sizes as incand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neon Sign
In the signage industry, neon signs are electric signs lighted by long luminous gas-discharge tubes that contain rarefied neon or other gases. They are the most common use for neon lighting, which was first demonstrated in a modern form in December 1910 by Georges Claude at the Paris Motor Show. While they are used worldwide, neon signs were popular in the United States from about the 1920s to 1950s. The installations in Times Square, many originally designed by Douglas Leigh, were famed, and there were nearly 2,000 small shops producing neon signs by 1940. Pages 221–223 describe Moore tubes. Pages 369–374 describe neon tube lighting. Page 385 discusses Risler's contributions to fluorescent coatings in the 1920s. Pages 388–391 discuss the development of the commercial fluorescent at General Electric in the 1930s. In addition to signage, neon lighting is used frequently by artists and architects, and (in a modified form) in plasma display panels and televisions. Paid access ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Flare
A solar flare is an intense localized eruption of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and other solar phenomena. The occurrence of solar flares varies with the 11-year solar cycle. Solar flares are thought to occur when stored magnetic energy in the Sun's atmosphere accelerates charged particles in the surrounding plasma. This results in the emission of electromagnetic radiation across the electromagnetic spectrum. High-energy electromagnetic radiation from solar flares is absorbed by the daylight side of Earth's upper atmosphere, in particular the ionosphere, and does not reach the surface. This absorption can temporarily increase the ionization of the ionosphere which may interfere with short-wave radio communication. The prediction of solar flares is an active area of research. Flares also occur on other stars, where the term ''stellar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
