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Magnetospheric Convection And Magnetic Storms
A geomagnetic storm, also known as a magnetic storm, is a temporary disturbance of the Earth's magnetosphere caused by a solar wind shock wave and/or cloud of magnetic field that interacts with the Earth's magnetic field. The disturbance that drives the magnetic storm may be a solar coronal mass ejection (CME) or (much less severely) a co-rotating interaction region (CIR), a high-speed stream of solar wind originating from a coronal hole. The frequency of geomagnetic storms increases and decreases with the sunspot cycle. During solar maximum, geomagnetic storms occur more often, with the majority driven by CMEs. The increase in the solar wind pressure initially compresses the magnetosphere. The solar wind's magnetic field interacts with the Earth's magnetic field and transfers an increased energy into the magnetosphere. Both interactions cause an increase in plasma movement through the magnetosphere (driven by increased electric fields inside the magnetosphere) and an increas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetosphere Rendition
In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior Dynamo theory, dynamo. In the space environment close to a planetary body, the magnetic field resembles a magnetic dipole. Farther out, field lines can be significantly distorted by the flow of electrically conducting plasma (physics), plasma, as emitted from the Sun (i.e., the solar wind) or a nearby star. Planets having active magnetospheres, like the Earth, are capable of mitigating or blocking the effects of solar radiation or cosmic radiation, that also protects all living organisms from potentially detrimental and dangerous consequences. This is studied under the specialized scientific subjects of plasma physics, space physics and aeronomy. History Study of Earth's magnetosphere began in 1600, when William Gilbert (astronomer), William G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aurora (astronomy)
An aurora (plural: auroras or aurorae), also commonly known as the polar lights, is a natural light display in Earth's sky, predominantly seen in high-latitude regions (around the Arctic and Antarctic). Auroras display dynamic patterns of brilliant lights that appear as curtains, rays, spirals, or dynamic flickers covering the entire sky. Auroras are the result of disturbances in the magnetosphere caused by the solar wind. Major disturbances result from enhancements in the speed of the solar wind from coronal holes and coronal mass ejections. These disturbances alter the trajectories of charged particles in the magnetospheric plasma. These particles, mainly electrons and protons, precipitate into the upper atmosphere (thermosphere/ exosphere). The resulting ionization and excitation of atmospheric constituents emit light of varying colour and complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of accelerati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Observatory (journal)
''The Observatory'' is a publication, variously described as a journal, a magazine and a review, devoted to astronomy. It appeared regularly starting in 1877, and it is now published every two months. The current editors are David Stickland, Bob Argyle and Steve Fossey. Although it is not published by the Royal Astronomical Society, it publishes the reports of its meetings. Other features are the extensive book reviews and "Here and There", a collection of misprints and ridiculous statements of astronomical interest. The founder and first editor (1877–1882) was William Christie, then chief assistant at the Royal Observatory and later Astronomer Royal. Notable subsequent editors include: * Arthur Eddington (1913–1919) * Harold Spencer Jones (1915–1923) * Richard van der Riet Woolley (1933–1939) * William McCrea (1935–1937) * Margaret Burbidge (1948–1951) * Antony Hewish (1957–1961) * Donald Lynden-Bell (1967–1969) * Carole Jordan (1968–1973) * Jocelyn Bel ... [...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 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] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2019 ''Journal Citation Reports'' (with an ascribed impact factor of 42.778), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in autumn 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander Macmillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the journal; ''Nature'' redoubled its efforts in exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sydney Chapman (mathematician)
Sydney Chapman (29 January 1888 – 16 June 1970) was a British mathematician and geophysicist. His work on the kinetic theory of gases, solar-terrestrial physics, and the Earth's ozone layer has inspired a broad range of research over many decades. Education and early life Chapman was born in Eccles, near Salford in England and began his advanced studies at a technical institute, now the University of Salford, in 1902. In 1904 at age 16, Chapman entered the University of Manchester. He competed for a scholarship to the university offered by his home county, and was the last student selected. Chapman later reflected, "I sometimes wonder what would have happened if I'd hit one place lower." He initially studied engineering in the department headed by Osborne Reynolds. Chapman was taught mathematics by Horace Lamb, the Beyer professor of mathematics, and J. E. Littlewood, who came from Cambridge in Chapman's final year at Manchester. Although he graduated with an engineerin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Oceanic And Atmospheric Administration
The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditions, charts the seas, conducts deep sea exploration, and manages fishing and protection of marine mammals and endangered species in the U.S. exclusive economic zone. Purpose and function NOAA's specific roles include: * ''Supplying Environmental Information Products''. NOAA supplies to its customers and partners information pertaining to the state of the oceans and the atmosphere, such as weather warnings and forecasts via the National Weather Service. NOAA's information services extend as well to climate, ecosystems, and commerce. * ''Providing Environmental Stewardship Services''. NOAA is a steward of U.S. coastal and marine environments. In coordination with federal, state, local, tribal and international authorities, NOAA manages the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A-index
The ''K''-index quantifies disturbances in the horizontal component of earth's magnetic field with an integer in the range 0–9 with 1 being calm and 5 or more indicating a geomagnetic storm. It is derived from the maximum fluctuations of horizontal components observed on a magnetometer during a three-hour interval. The label ''K'' comes from the German word ''Kennziffer'' meaning "''characteristic digit''". The ''K''-index was introduced by Julius Bartels in 1939. Calculation of ''K''-index The ''K''-scale is quasi-logarithmic. The conversion table from maximum fluctuation ''R'' (in units of nano teslas, nT) to ''K''-index, varies from observatory to observatory in such a way that the historical rate of occurrence of certain levels of ''K'' are about the same at all observatories. In practice this means that observatories at higher geomagnetic latitude require higher levels of fluctuation for a given ''K''-index. For example, at Godhavn, Greenland, a value of '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K-index
The ''K''-index quantifies disturbances in the horizontal component of earth's magnetic field with an integer in the range 0–9 with 1 being calm and 5 or more indicating a geomagnetic storm. It is derived from the maximum fluctuations of horizontal components observed on a magnetometer during a three-hour interval. The label ''K'' comes from the German word ''Kennziffer'' meaning "''characteristic digit''". The ''K''-index was introduced by Julius Bartels in 1939. Calculation of ''K''-index The ''K''-scale is quasi-logarithmic. The conversion table from maximum fluctuation ''R'' (in units of nano teslas, nT) to ''K''-index, varies from observatory to observatory in such a way that the historical rate of occurrence of certain levels of ''K'' are about the same at all observatories. In practice this means that observatories at higher geomagnetic latitude require higher levels of fluctuation for a given ''K''-index. For example, at Godhavn, Greenland, a value of '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aurora Borealis2, Churchill, MB
An aurora (plural: auroras or aurorae), also commonly known as the polar lights, is a natural light display in Earth's sky, predominantly seen in high-latitude regions (around the Arctic and Antarctic). Auroras display dynamic patterns of brilliant lights that appear as curtains, rays, spirals, or dynamic flickers covering the entire sky. Auroras are the result of disturbances in the magnetosphere caused by the solar wind. Major disturbances result from enhancements in the speed of the solar wind from coronal holes and coronal mass ejections. These disturbances alter the trajectories of charged particles in the magnetospheric plasma. These particles, mainly electrons and protons, precipitate into the upper atmosphere (thermosphere/exosphere). The resulting ionization and excitation of atmospheric constituents emit light of varying colour and complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of acceleration imp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tesla (unit)
The tesla (symbol: T) is the unit of magnetic flux density (also called magnetic B-field strength) in the International System of Units (SI). One tesla is equal to one weber per square metre. The unit was announced during the General Conference on Weights and Measures in 1960 and is named in honour of Serbian-American electrical and mechanical engineer Nikola Tesla, upon the proposal of the Slovenian electrical engineer France Avčin. Definition A particle, carrying a charge of one coulomb (C), and moving perpendicularly through a magnetic field of one tesla, at a speed of one metre per second (m/s), experiences a force with magnitude one newton (N), according to the Lorentz force law. That is, : \text = \dfrac. As an SI derived unit, the tesla can also be expressed in terms of other units. For example, a magnetic flux of 1 weber (Wb) through a surface of one square meter is equal to a magnetic flux density of 1 tesla.''The International System of Units (SI), 8th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
