|
Plasmapause
The plasmasphere, or inner magnetosphere, is a region of the Earth's magnetosphere consisting of low-energy (cool) plasma. It is located above the ionosphere. The outer boundary of the plasmasphere is known as the plasmapause, which is defined by an order of magnitude drop in plasma density. In 1963 American scientist Don Carpenter and Soviet astronomer proved the plasmasphere and plasmapause's existence from the analysis of very low frequency (VLF) whistler wave data. Traditionally, the plasmasphere has been regarded as a well behaved cold plasma with particle motion dominated entirely by the geomagnetic field and, hence, co-rotating with the Earth. History The discovery of the plasmasphere grew out of the scientific study of whistlers, natural phenomena caused by very low frequency (VLF) radio waves. Whistlers were first heard by radio operators in the 1890s. British scientist Llewelyn Robert Owen Storey had shown lightning generated whistlers in his 1953 PhD dissertation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Don Carpenter (electrical Engineer)
The plasmasphere, or inner magnetosphere, is a region of the Earth's magnetosphere consisting of low-energy (cool) plasma. It is located above the ionosphere. The outer boundary of the plasmasphere is known as the plasmapause, which is defined by an order of magnitude drop in plasma density. In 1963 American scientist Don Carpenter and Soviet astronomer proved the plasmasphere and plasmapause's existence from the analysis of very low frequency (VLF) whistler wave data. Traditionally, the plasmasphere has been regarded as a well behaved cold plasma with particle motion dominated entirely by the geomagnetic field and, hence, co-rotating with the Earth. History The discovery of the plasmasphere grew out of the scientific study of whistlers, natural phenomena caused by very low frequency (VLF) radio waves. Whistlers were first heard by radio operators in the 1890s. British scientist Llewelyn Robert Owen Storey had shown lightning generated whistlers in his 1953 PhD dissertation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magneto Plasma Sphere
A magneto is an electrical generator that uses permanent magnets to produce periodic pulses of alternating current. Unlike a dynamo, a magneto does not contain a commutator to produce direct current. It is categorized as a form of alternator, although it is usually considered distinct from most other alternators, which use field coils rather than permanent magnets. Hand-cranked magneto generators were used to provide ringing current in telephone systems. Magnetos were also adapted to produce pulses of high voltage in the ignition systems of some gasoline-powered internal combustion engines to provide power to the spark plugs. Use of such ignition magnetos for ignition is now limited mainly to engines without a low-voltage electrical system, such as lawnmowers and chainsaws, and to aircraft engines, in which keeping the ignition independent of the rest of the electrical system ensures that the engine continues running in the event of alternator or battery failure. For redundancy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FR-1 (satellite)
FR-1 was the second French satellite. Planned as the first French satellite, it was launched on 6 December 1965—ten days after the actual first French satellite, ''Astérix''—by an American Scout X-4 rocket from the Western Range at Vandenberg Air Force Base. The scientific satellite studied the composition and structure of the ionosphere, plasmasphere, and magnetosphere by measuring the propagation of very low frequency (VLF) waves and the electron density of plasma in those portions of the Earth's atmosphere. FR-1's VLF receiver operated until 26 August 1968. FR-1 remains in orbit as of 2023. Background FR-1 was the first step of an ambitious French plan to launch six FR-series satellites, each meant to study a different aspect of the Earth's atmosphere. FR-1 was generally designed to study the Earth's magnetic and electric fields in the ionosphere and magnetosphere. The satellite ''Astérix''—ultimately France's first satellite, launched ten days before FR-1—was i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetosphere Chronology
The following is a chronology of discoveries concerning the magnetosphere. *1600 - William Gilbert in London suggests the Earth is a giant magnet. *1741 - Hiorter and Anders Celsius note that the polar aurora is accompanied by a disturbance of the magnetic needle. *1820 - Hans Christian Ørsted discovers electric currents create magnetic effects. André-Marie Ampère deduces that magnetism is basically the force between electric currents. *1833 - Carl Friedrich Gauss and Wilhelm Weber worked out the mathematical theory for separating the inner and outer Magnetosphere sources of Earth's magnetic field. *1843 - Samuel Schwabe, a German amateur astronomer, shows the existence of an 11-year sunspot cycle. *1859 - Richard Carrington in England observes a solar flare; 17 hours later a large magnetic storm begins. *1892 - George Ellery Hale introduces the spectroheliograph, observing the Sun in hydrogen light from the chromosphere, a sensitive way of detecting flares. He confirms t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IMAGE (spacecraft)
IMAGE (Imager for Magnetopause-to-Aurora Global Exploration, Explorer 78 or MIDEX-1) is a NASA Medium Explorer mission that studied the global response of the Earth's magnetosphere to changes in the solar wind. It was believed lost but as of August 2018 might be recoverable. It was launched 25 March 2000, at 20:34:43.929 UTC, by a Delta II launch vehicle from Vandenberg Air Force Base on a two-year mission. Almost six years later, it unexpectedly ceased operations in December 2005 during its extended mission and was declared lost. The spacecraft was part of NASA's Sun-Earth Connections Program, and its data has been used in over 400 research articles published in peer-reviewed journals. It had special cameras that provided various breakthroughs in understanding the dynamics of plasma around the Earth. The principal investigator was Jim Burch of the Southwest Research Institute. In January 2018, an amateur satellite tracker found it to be transmitting some signals bac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Angeles Times
The ''Los Angeles Times'' (abbreviated as ''LA Times'') is a daily newspaper that started publishing in Los Angeles in 1881. Based in the LA-adjacent suburb of El Segundo since 2018, it is the sixth-largest newspaper by circulation in the United States. The publication has won more than 40 Pulitzer Prizes. It is owned by Patrick Soon-Shiong and published by the Times Mirror Company. The newspaper’s coverage emphasizes California and especially Southern California stories. In the 19th century, the paper developed a reputation for civic boosterism and opposition to labor unions, the latter of which led to the bombing of its headquarters in 1910. The paper's profile grew substantially in the 1960s under publisher Otis Chandler, who adopted a more national focus. In recent decades the paper's readership has declined, and it has been beset by a series of ownership changes, staff reductions, and other controversies. In January 2018, the paper's staff voted to unionize a ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmic Ray
Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own galaxy, and from distant galaxies. Upon impact with Earth's atmosphere, cosmic rays produce showers of secondary particles, some of which reach the surface, although the bulk is deflected off into space by the magnetosphere or the heliosphere. Cosmic rays were discovered by Victor Hess in 1912 in balloon experiments, for which he was awarded the 1936 Nobel Prize in Physics. Direct measurement of cosmic rays, especially at lower energies, has been possible since the launch of the first satellites in the late 1950s. Particle detectors similar to those used in nuclear and high-energy physics are used on satellites and space probes for research into cosmic rays. Data from the Fermi Space Telescope (2013) have been interpreted as evidence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrarelativistic Limit
In physics, a particle is called ultrarelativistic when its speed is very close to the speed of light . The expression for the relativistic energy of a particle with rest mass and momentum is given by :E^2 = m^2 c^4 + p^2 c^2. The energy of an ultrarelativistic particle is almost completely due to its momentum (), and thus can be approximated by . This can result from holding the mass fixed and increasing to very large values (the usual case); or by holding the energy fixed and shrinking the mass to negligible values. The latter is used to derive orbits of massless particles such as the photon from those of massive particles (cf. Kepler problem in general relativity). In general, the ultrarelativistic limit of an expression is the resulting simplified expression when pc \gg mc^2 is assumed. Or, similarly, in the limit where the Lorentz factor \gamma = 1/\sqrt is very large (\gamma \gg 1). Expression including mass value While it is possible to use the approximation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Van Allen Probes
The Van Allen Probes, formerly known as the Radiation Belt Storm Probes (RBSP), were two robotic spacecraft that were used to study the Van Allen radiation belts that surround Earth. NASA conducted the Van Allen Probes mission as part of the Living With a Star program. Understanding the radiation belt environment and its variability has practical applications in the areas of spacecraft operations, spacecraft system design, mission planning and astronaut safety. The probes were launched on 30 August 2012 and operated for seven years. Both spacecraft were deactivated in 2019 when they ran out of fuel. They are expected to deorbit during the 2030s. Overview NASA's Goddard Space Flight Center manages the overall Living With a Star program of which RBSP is a project, along with Solar Dynamics Observatory (SDO). The Johns Hopkins University Applied Physics Laboratory (APL) was responsible for the overall implementation and instrument management for RBSP. The primary mission was schedu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
THEMIS
In Greek mythology and religion, Themis (; grc, Θέμις, Themis, justice, law, custom) is one of the twelve Titan children of Gaia and Uranus, and the second wife of Zeus. She is the goddess and personification of justice, divine order, fairness, law, and custom, and her symbols include the Scales of Justice. She is also associated with oracles and prophecies, including the Oracle of Delphi. Name ''Themis'' means "divine law" rather than human ordinance, literally "that which is put in place", from the Greek verb ''títhēmi'' ( τίθημι), meaning "to put." To the ancient Greeks she was originally the organizer of the "communal affairs of humans, particularly assemblies." Moses Finley remarked of ''themis'', as the word was used by Homer in the 8th century BCE, to evoke the social order of the 10th- and 9th-century Greek Dark Ages: Finley adds, "There was ''themis''—custom, tradition, folk-ways, ''mores'', whatever we may call it, the enormous power of 'it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which is small CubeSats. Similar satellites can work together as a group, forming constellations. Because of the high launch cost to space, satellites are designed to be as lightweight and robust as possible. Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Satellites are placed from the surface to orbit by launch vehicles, high enough to avoid orbital decay by the atmosphere. Satellites can then change or maintain the orbit by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
