Fire Serpent is a 2007 Sci Fi Channel monster movie directed by John Terlesky .
90-473: A solar flare from the sun sends a serpentine alien composed of fire to Earth where it begins to wreak havoc throughout a small community. During its search for more fuel to consume it stumbles upon a large military oil reserve . It soon becomes clear that an old man may hold the key to destroying it in the form of a Halogen Gun which may be used as a makeshift fire extinguisher of sorts. A small group of citizens decides to use this technology to make
180-414: A magnetic crochet , a magnetic field detected by ground-based magnetometers induced by a perturbation of Earth's ionosphere by ionizing soft X-rays . This could not easily be understood at the time because it predated the discovery of X-rays in 1895 and the recognition of the ionosphere in 1902. About 18 hours after the flare, further geomagnetic perturbations were recorded by multiple magnetometers as
270-473: A current sheet above the PIL. Fast magnetic reconnection can be excited along the current sheet by microscopic instabilities, resulting in the rapid release of stored magnetic energy as kinetic, thermal, and nonthermal energy. The restructuring of the magnetic field cuts the strapping field's connections to the photosphere thereby decreasing the downward magnetic tension force while the upward reconnection outflow pushes
360-440: A magnetic crochet . The latter term derives from the french word crochet meaning hook reflecting the hook-like disturbances in magnetic field strength observed by ground-based magnetometers . These disturbances are on the order of a few nanoteslas and last for a few minutes, which is relatively minor compared to those induced during geomagnetic storms. For astronauts in low Earth orbit , an expected radiation dose from
450-419: A CME can greatly affect how it interacts with Earth's magnetic field. This interaction can result in the conservation or loss of magnetic flux, particularly its southward magnetic field component, through magnetic reconnection with the interplanetary magnetic field . In the solar wind, CMEs manifest as magnetic clouds . They have been defined as regions of enhanced magnetic field strength, smooth rotation of
540-683: A CME involves its initiation from a pre-eruption structure in the corona and the acceleration that follows. The processes involved in the early evolution of CMEs are poorly understood due to a lack of observational evidence. CME initiation occurs when a pre-eruption structure in an equilibrium state enters a nonequilibrium or metastable state where energy can be released to drive an eruption. The specific processes involved in CME initiation are debated, and various models have been proposed to explain this phenomenon based on physical speculation. Furthermore, different CMEs may be initiated by different processes. It
630-485: A CME, coincided with the first-observed solar flare on 1 September 1859. The resulting solar storm of 1859 is referred to as the Carrington Event . The flare and the associated sunspots were visible to the naked eye, and the flare was independently observed by English astronomers R. C. Carrington and R. Hodgson . At around the same time as the flare, a magnetometer at Kew Gardens recorded what would become known as
720-446: A CME, was the solar storm of 1859 . Also known as the Carrington Event , it disabled parts of the newly created United States telegraph network, starting fires and electrically shocking some telegraph operators. Near solar maxima , the Sun produces about three CMEs every day, whereas near solar minima , there is about one CME every five days. CMEs release large quantities of matter from
810-401: A class is noted by a numerical suffix ranging from 1 up to, but excluding, 10, which is also the factor for that event within the class. Hence, an X2 flare is twice the strength of an X1 flare, an X3 flare is three times as powerful as an X1. M-class flares are a tenth the size of X-class flares with the same numeric suffix. An X2 is four times more powerful than an M5 flare. X-class flares with
900-422: A fast CME by a satellite such as ACE is a fast-mode shock wave followed by a dense (and hot) sheath of plasma (the downstream region of the shock) and a magnetic cloud. Other signatures of magnetic clouds are now used in addition to the one described above: among other, bidirectional superthermal electrons , unusual charge state or abundance of iron , helium , carbon , and/or oxygen . The typical time for
990-436: A helix of magnetic field unconnected to the rest of the arcade. The sudden release of energy in this reconnection is the origin of the particle acceleration. The unconnected magnetic helical field and the material that it contains may violently expand outwards forming a coronal mass ejection. This also explains why solar flares typically erupt from active regions on the Sun where magnetic fields are much stronger. Although there
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#17332018609451080-587: A lesser extent, that of Venus . The impacts on other planets in the Solar System are little studied in comparison. As of 2024, research on their effects on Mercury have been limited to modeling of the response of ions in the planet's magnetosphere , and their impact on Jupiter and Saturn have only been studied in the context of X-ray radiation back scattering off of the planets' upper atmospheres. Enhanced XUV irradiance during solar flares can result in increased ionization , dissociation , and heating in
1170-448: A magnetic cloud to move past a satellite at the L1 point is 1 day corresponding to a radius of 0.15 AU with a typical speed of 450 km/s (280 mi/s) and magnetic field strength of 20 nT . The frequency of ejections depends on the phase of the solar cycle : from about 0.2 per day near the solar minimum to 3.5 per day near the solar maximum . However, the peak CME occurrence rate
1260-510: A part of a geomagnetic storm . The storm disabled parts of the recently created US telegraph network, starting fires and shocking some telegraph operators. The first optical observation of a CME was made on 14 December 1971 using the coronagraph of Orbiting Solar Observatory 7 (OSO-7). It was first described by R. Tousey of the Naval Research Laboratory in a research paper published in 1973. The discovery image (256 × 256 pixels)
1350-555: A peak flux that exceeds 10 W/m may be noted with a numerical suffix equal to or greater than 10. This system was originally devised in 1970 and included only the letters C, M, and X. These letters were chosen to avoid confusion with other optical classification systems. The A and B classes were added in the 1990s as instruments became more sensitive to weaker flares. Around the same time, the backronym moderate for M-class flares and extreme for X-class flares began to be used. An earlier classification system, sometimes referred to as
1440-420: A result of the dominance of magnetic field processes in the lower corona, the majority of the energy must be stored as magnetic energy . The magnetic energy that is freely available to be released from a pre-eruption structure, referred to as the magnetic free energy or nonpotential energy of the structure, is the excess magnetic energy stored by the structure's magnetic configuration relative to that stored by
1530-463: A stand against the creature only to face additional resistance from the beast, as well as a government employer who voluntarily helps the snake because he believes it is the spirit of a god. David Cornelius from DVD Talk gave the film a negative review, writing, " Fire Serpent is a wretched sci-fi/horror mess, with laughable CGI effects, an empty plot, and zero suspense. (In other words, it's your run-of-the-mill Sci-Fi Channel production. Zing!) It's
1620-484: Is a general agreement on the source of a flare's energy, the mechanisms involved are not well understood. It is not clear how the magnetic energy is transformed into the kinetic energy of the particles, nor is it known how some particles can be accelerated to the GeV range (10 electron volt ) and beyond. There are also some inconsistencies regarding the total number of accelerated particles, which sometimes seems to be greater than
1710-455: Is a relatively intense, localized emission 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 eruptive 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
1800-641: Is a significant ejection of plasma mass from the Sun's corona into the heliosphere . CMEs are often associated with solar flares and other forms of solar activity , but a broadly accepted theoretical understanding of these relationships has not been established. If a CME enters interplanetary space , it is referred to as an interplanetary coronal mass ejection ( ICME ). ICMEs are capable of reaching and colliding with Earth's magnetosphere , where they can cause geomagnetic storms , aurorae , and in rare cases damage to electrical power grids . The largest recorded geomagnetic perturbation, resulting presumably from
1890-425: Is heated to >10 kelvin , while electrons , protons , and heavier ions are accelerated to near the speed of light . Flares emit electromagnetic radiation across the electromagnetic spectrum , from radio waves to gamma rays . Flares occur in active regions , often around sunspots , where intense magnetic fields penetrate the photosphere to link the corona to the solar interior. Flares are powered by
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#17332018609451980-467: Is often 6–12 months after sunspot number reaches its maximum. Only a very small fraction of CMEs are directed toward, and reach, the Earth. A CME arriving at Earth results in a shock wave causing a geomagnetic storm that may disrupt Earth's magnetosphere , compressing it on the day side and extending the night-side magnetic tail . When the magnetosphere reconnects on the nightside, it releases power on
2070-428: Is subject to ongoing debate. Some pre-eruption structures have been observed to support prominences , also known as filaments, composed of much cooler material than the surrounding coronal plasma. Prominences are embedded in magnetic field structures referred to as prominence cavities, or filament channels, which may constitute part of a pre-eruption structure (see § Coronal signatures ). The early evolution of
2160-413: Is then classified taking S or a number that represents its size and a letter that represents its peak intensity, v.g.: Sn is a normal sunflare. A common measure of flare duration is the full width at half maximum (FWHM) time of flux in the soft X-ray bands 0.05 to 0.4 and 0.1 to 0.8 nm measured by GOES. The FWHM time spans from when a flare's flux first reaches halfway between its maximum flux and
2250-550: Is thought to be continued by prolonged heating present after the eruption and during the flare's decay stage. In sufficiently powerful flares, typically of C-class or higher, the loops may combine to form an elongated arch-like structure known as a post-eruption arcade . These structures may last anywhere from multiple hours to multiple days after the initial flare. In some cases, dark sunward-traveling plasma voids known as supra-arcade downflows may form above these arcades. The frequency of occurrence of solar flares varies with
2340-611: Is unknown whether a magnetic flux rope exists prior to initiation, in which case either ideal or non-ideal magnetohydrodynamic (MHD) processes drive the expulsion of this flux rope, or whether a flux rope is created during the eruption by non-ideal process. Under ideal MHD, initiation may involve ideal instabilities or catastrophic loss of equilibrium along an existing flux rope: Under non-ideal MHD, initiations mechanisms may involve resistive instabilities or magnetic reconnection : Following initiation, CMEs are subject to different forces that either assist or inhibit their rise through
2430-586: The Thomson scattering of sunlight off of free electrons within the CME plasma. An observed CME may have any or all of three distinctive features: a bright core, a dark surrounding cavity, and a bright leading edge. The bright core is usually interpreted as a prominence embedded in the CME (see § Origin ) with the leading edge as an area of compressed plasma ahead of the CME flux rope. However, some CMEs exhibit more complex geometry. From white-light coronagraph observations, CMEs have been measured to reach speeds in
2520-406: The flare importance , was based on H-alpha spectral observations. The scheme uses both the intensity and emitting surface. The classification in intensity is qualitative, referring to the flares as: faint (f), normal (n), or brilliant (b). The emitting surface is measured in terms of millionths of the hemisphere and is described below. (The total hemisphere area A H = 15.5 × 10 km .) A flare
2610-528: The ionospheres of Earth and Earth-like planets. On Earth, these changes to the upper atmosphere, collectively referred to as sudden ionospheric disturbances , can interfere with short-wave radio communication and global navigation satellite systems (GNSS) such as GPS , and subsequent expansion of the upper atmosphere can increase drag on satellites in low Earth orbit leading to orbital decay over time. Flare-associated XUV photons interact with and ionize neutral constituents of planetary atmospheres via
2700-399: The plasma medium. Evidence suggests that the phenomenon of magnetic reconnection leads to this extreme acceleration of charged particles. On the Sun, magnetic reconnection may happen on solar arcades – a type of prominence consisting of a series of closely occurring loops following magnetic lines of force. These lines of force quickly reconnect into a lower arcade of loops leaving
2790-401: The solar dynamo . These magnetic fields rise to the Sun's surface—the photosphere —where they may form localized areas of highly concentrated magnetic flux and expand into the lower solar atmosphere forming active regions . At the photosphere, active region magnetic flux is often distributed in a dipole configuration , that is, with two adjacent areas of opposite magnetic polarity across which
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2880-466: The 11-year solar cycle . It can typically range from several per day during solar maxima to less than one every week during solar minima . Additionally, more powerful flares are less frequent than weaker ones. For example, X10-class (severe) flares occur on average about eight times per cycle, whereas M1-class (minor) flares occur on average about 2000 times per cycle. Erich Rieger discovered with coworkers in 1984, an approximately 154 day period in
2970-401: The CME as eruptive prominences. Eruptive prominences are associated with at least 70% of all CMEs and are often embedded within the bases of CME flux ropes. When observed in white-light coronagraphs, the eruptive prominence material, if present, corresponds to the observed bright core of dense material. When magnetic reconnection is excited along a current sheet of a rising CME core structure,
3060-504: The CME structure upwards. A positive feedback loop results as the core is pushed upwards and the sides of the strapping field are brought in closer and closer contact to produce additional magnetic reconnection and rise. While upward reconnection outflow accelerates the core, simultaneous downward outflow is sometimes responsible for other phenomena associated with CMEs (see § Coronal signatures ). In cases where significant magnetic reconnection does not occur, ideal MHD instabilities or
3150-501: The Earth resulting in gradual solar particle events . Interactions between these energetic particles and the Earth can cause an increase in the number of free electrons in the ionosphere , especially in the high-latitude polar regions, enhancing radio wave absorption, especially within the D-region of the ionosphere, leading to polar cap absorption events. The interaction of CMEs with the Earth's magnetosphere leads to dramatic changes in
3240-527: The International Solar Terrestrial Physics (ISTP) program. The spacecraft is a spin axis-stabilized satellite that carries eight instruments measuring solar wind particles from thermal to greater than MeV energies, electromagnetic radiation from DC to 13 MHz radio waves, and gamma-rays. On 25 October 2006, NASA launched STEREO , two near-identical spacecraft which, from widely separated points in their orbits, are able to produce
3330-543: The Sun with wavelengths shorter than 300 nm, space-based telescopes allowed for the observation of solar flares in previously unobserved high-energy spectral lines. Since the 1970s, the GOES series of satellites have been continuously observing the Sun in soft X-rays, and their observations have become the standard measure of flares, diminishing the importance of the H-alpha classification. Additionally, space-based telescopes allow for
3420-415: The Sun's atmosphere accelerates charged particles in the surrounding plasma . This results in the emission of electromagnetic radiation across the electromagnetic spectrum . The extreme ultraviolet and X-ray 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
3510-598: The Sun's atmosphere into the solar wind and interplanetary space . The ejected matter is a plasma consisting primarily of electrons and protons embedded within its magnetic field. This magnetic field is commonly in the form of a flux rope, a helical magnetic field with changing pitch angles . The average mass ejected is 1.6 × 10 kg (3.5 × 10 lb). However, the estimated mass values for CMEs are only lower limits, because coronagraph measurements provide only two-dimensional data. CMEs erupt from strongly twisted or sheared, large-scale magnetic field structures in
3600-455: The Sun, CMEs are sometimes referred to as interplanetary CMEs , or ICMEs . As CMEs propagate through the heliosphere, they may interact with the surrounding solar wind, the interplanetary magnetic field, and other CMEs and celestial bodies. CMEs can experience aerodynamic drag forces that act to bring them to kinematic equilibrium with the solar wind. As a consequence, CMEs faster than the solar wind tend to slow down whereas CMEs slower than
3690-553: The Sun, are thought to occur and have been observed on other Sun-like stars . Flares produce radiation across the electromagnetic spectrum, although with different intensity. They are not very intense in visible light, but they can be very bright at particular spectral lines . They normally produce bremsstrahlung in X-rays and synchrotron radiation in radio. Solar flares were first observed by Richard Carrington and Richard Hodgson independently on 1 September 1859 by projecting
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3780-605: The ambient electrons and neutral species and via secondary ionization due to collisions with the latter, or so-called photoelectron impact ionization . In the process of thermalization, photoelectrons transfer energy to neutral species, resulting in heating and expansion of the neutral atmosphere. The greatest increases in ionization occur in the lower ionosphere where wavelengths with the greatest relative increase in irradiance—the highly penetrative X-ray wavelengths—are absorbed, corresponding to Earth's E and D layers and Mars's M 1 layer. The temporary increase in ionization of
3870-447: The background flux and when it again reaches this value as the flare decays. Using this measure, the duration of a flare ranges from approximately tens of seconds to several hours with a median duration of approximately 6 and 11 minutes in the 0.05 to 0.4 and 0.1 to 0.8 nm bands, respectively. Flares can also be classified based on their duration as either impulsive or long duration events ( LDE ). The time threshold separating
3960-479: The chance of Earth being hit by a Carrington-class storm in the next decade to be between 0.46% and 1.88%. CMEs have been observed indirectly for thousands of years via aurora. Other indirect observations that predated the discovery of CMEs were through measurements of geomagnetic perturbations, radioheliograph measurements of solar radio bursts, and in-situ measurements of interplanetary shocks. The largest recorded geomagnetic perturbation, resulting presumably from
4050-405: The corona that are kept in equilibrium by overlying magnetic fields. CMEs erupt from the lower corona, where processes associated with the local magnetic field dominate over other processes. As a result, the coronal magnetic field plays an important role in the formation and eruption of CMEs. Pre-eruption structures originate from magnetic fields that are initially generated in the Sun's interior by
4140-424: The daylight side of Earth's atmosphere, in particular the D layer of the ionosphere , can interfere with short-wave radio communications that rely on its level of ionization for skywave propagation. Skywave, or skip, refers to the propagation of radio waves reflected or refracted off of the ionized ionosphere. When ionization is higher than normal, radio waves get degraded or completely absorbed by losing energy from
4230-404: The distance from its source region . The excess ionizing radiation , namely X-ray and extreme ultraviolet (XUV) radiation, is known to affect planetary atmospheres and is of relevance to human space exploration and the search for extraterrestrial life. Solar flares also affect other objects in the Solar System. Research into these effects has primarily focused on the atmosphere of Mars and, to
4320-514: The downward reconnection outflows can collide with loops below to form a cusp-shaped, two-ribbon solar flare. CME eruptions can also produce EUV waves, also known as EIT waves after the Extreme ultraviolet Imaging Telescope or as Moreton waves when observed in the chromosphere, which are fast-mode MHD wave fronts that emanate from the site of the CME. A coronal dimming is a localized decrease in extreme ultraviolet and soft X-ray emissions in
4410-540: The dragging force from the solar wind can theoretically accelerate a CME. However, if sufficient acceleration is not provided, the CME structure may fall back in what is referred to as a failed or confined eruption . The early evolution of CMEs is frequently associated with other solar phenomena observed in the low corona, such as eruptive prominences and solar flares. CMEs that have no observed signatures are sometimes referred to as stealth CMEs . Prominences embedded in some CME pre-eruption structures may erupt with
4500-674: The electromagnetic radiation emitted during a solar flare is about 0.05 gray , which is not immediately lethal on its own. Of much more concern for astronauts is the particle radiation associated with solar particle events. The impacts of solar flare radiation on Mars are relevant to exploration and the search for life on the planet . Models of its atmosphere indicate that the most energetic solar flares previously recorded may have provided acute doses of radiation that would have been almost harmful or lethal to mammals and other higher organisms on Mars's surface. Furthermore, flares energetic enough to provide lethal doses, while not yet observed on
4590-422: The erupting flux rope; secondary dimmings are interpreted as the result of the expansion of the overall CME structure and are generally more diffuse and shallow. Coronal dimming was first reported in 1974, and, due to their appearance resembling that of coronal holes , they were sometimes referred to as transient coronal holes . Observations of CMEs are typically through white-light coronagraphs which measure
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#17332018609454680-422: The event. Using these magnetometer readings, its soft X-ray class has been estimated to be greater than X10 and around X45 (±5). In modern times, the largest solar flare measured with instruments occurred on 4 November 2003 . This event saturated the GOES detectors, and because of this, its classification is only approximate. Initially, extrapolating the GOES curve, it was estimated to be X28. Later analysis of
4770-481: The evolution of some ICMEs, but not all of them. CMEs typically reach Earth one to five days after leaving the Sun. The strongest deceleration or acceleration occurs close to the Sun, but it can continue even beyond Earth orbit (1 AU ), which was observed using measurements at Mars and by the Ulysses spacecraft . ICMEs faster than about 500 km/s (310 mi/s) eventually drive a shock wave . This happens when
4860-453: The famous Carrington event in 1859 had several eruptions and caused auroras to be visible at low latitudes for four nights. Similarly, the solar storm of September 1770 lasted for nearly nine days, and caused repeated low-latitude auroras. The interaction between two moderate CMEs between the Sun and Earth can create extreme conditions on Earth. Recent studies have shown that the magnetic structure in particular its chirality /handedness, of
4950-559: The first stereoscopic images of CMEs and other solar activity measurements. The spacecraft orbit the Sun at distances similar to that of Earth, with one slightly ahead of Earth and the other trailing. Their separation gradually increased so that after four years they were almost diametrically opposite each other in orbit. On 9 March 1989, a CME occurred, which struck Earth four days later on 13 March. It caused power failures in Quebec, Canada and short-wave radio interference. On 23 July 2012,
5040-457: The image of the solar disk produced by an optical telescope through a broad-band filter. It was an extraordinarily intense white light flare , a flare emitting a high amount of light in the visual spectrum . Since flares produce copious amounts of radiation at H-alpha , adding a narrow (≈1 Å) passband filter centered at this wavelength to the optical telescope allows the observation of not very bright flares with small telescopes. For years Hα
5130-543: The image onto Polaroid print. David Roberts, an electronics technician working for NRL who had been responsible for the testing of the SEC-vidicon camera, was in charge of day-to-day operations. He thought that his camera had failed because certain areas of the image were much brighter than normal. But on the next image the bright area had moved away from the Sun and he immediately recognized this as being unusual and took it to his supervisor, Dr. Guenter Brueckner , and then to
5220-413: The interplanetary medium, they may collide with other ICMEs in what is referred to as CME–CME interaction or CME cannibalism . During such CME-CME interactions, the first CME may clear the way for the second one and/or when two CMEs collide it can lead to more severe impacts on Earth. Historical records show that the most extreme space weather events involved multiple successive CMEs. For example,
5310-444: 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 flare applies. Solar flares are eruptions of electromagnetic radiation originating in the Sun's atmosphere. They affect all layers of the solar atmosphere ( photosphere , chromosphere , and corona ). The plasma medium
5400-417: The ionosphere's dayside E layer inducing small-amplitude diurnal variations in the geomagnetic field. These ionospheric currents can be strengthened during large solar flares due to increases in electrical conductivity associated with enhanced ionization of the E and D layers. The subsequent increase in the induced geomagnetic field variation is referred to as a solar flare effect ( sfe ) or historically as
5490-525: The ionospheric effects suggested increasing this estimate to X45. This event produced the first clear evidence of a new spectral component above 100 GHz. Current methods of flare prediction are problematic, and there is no certain indication that an active region on the Sun will produce a flare. However, many properties of active regions and their sunspots correlate with flaring. For example, magnetically complex regions (based on line-of-sight magnetic field) referred to as delta spots frequently produce
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#17332018609455580-447: The kind of B picture that fails not because it's cheap, but because it's terminally dull." Jon Condit from Dread Central awarded the film a negative score of 1 out of five, calling it "dull". This article about a science-fiction horror film is a stub . You can help Misplaced Pages by expanding it . This article related to a Canadian TV movie is a stub . You can help Misplaced Pages by expanding it . Solar flare A solar flare
5670-494: The largest flares. A simple scheme of sunspot classification based on the McIntosh system for sunspot groups, or related to a region's fractal complexity is commonly used as a starting point for flare prediction. Predictions are usually stated in terms of probabilities for occurrence of flares above M- or X-class within 24 or 48 hours. The U.S. National Oceanic and Atmospheric Administration (NOAA) issues forecasts of this kind. MAG4
5760-400: The lower corona. Downward magnetic tension force exerted by the strapping magnetic field as it is stretched and, to a lesser extent, the gravitational pull of the Sun oppose movement of the core CME structure. In order for sufficient acceleration to be provided, past models have involved magnetic reconnection below the core field or an ideal MHD process, such as instability or acceleration from
5850-415: The lower corona. When associated with a CME, coronal dimmings are thought to occur predominantly due to a decrease in plasma density caused by mass outflows during the expansion of the associated CME. They often occur either in pairs located within regions of opposite magnetic polarity, a core dimming, or in a more widespread area, a secondary dimming. Core dimmings are interpreted as the footpoint locations of
5940-578: The lowest-energy magnetic configuration the underlying photospheric magnetic flux distribution could theoretically take, a potential field state. Emerging magnetic flux and photospheric motions continuously shifting the footpoints of a structure can result in magnetic free energy building up in the coronal magnetic field as twist or shear. Some pre-eruption structures, referred to as sigmoids , take on an S or reverse- S shape as shear accumulates. This has been observed in active region coronal loops and filaments with forward- S sigmoids more common in
6030-404: The magnetic field arches. Over time, the concentrated magnetic flux cancels and disperses across the Sun's surface, merging with the remnants of past active regions to become a part of the quiet Sun . Pre-eruption CME structures can be present at different stages of the growth and decay of these regions, but they always lie above polarity inversion lines (PIL), or boundaries across which the sign of
6120-413: The magnetic field vector, and low proton temperature. The association between CMEs and magnetic clouds was made by Burlaga et al. in 1982 when a magnetic cloud was observed by Helios-1 two days after being observed by SMM . However, because observations near Earth are usually done by a single spacecraft, many CMEs are not seen as being associated with magnetic clouds. The typical structure observed for
6210-536: The more frequent collisions with free electrons. The level of ionization of the atmosphere correlates with the strength of the associated solar flare in soft X-ray radiation. The Space Weather Prediction Center , a part of the United States National Oceanic and Atmospheric Administration , classifies radio blackouts by the peak soft X-ray intensity of the associated flare. During non-flaring or solar quiet conditions, electric currents flow through
6300-429: The observation of extremely long wavelengths—as long as a few kilometres—which cannot propagate through the ionosphere. The most powerful flare ever observed is thought to be the flare associated with the 1859 Carrington Event. While no soft X-ray measurements were made at the time, the magnetic crochet associated with the flare was recorded by ground-based magnetometers allowing the flare's strength to be estimated after
6390-688: The occulting disk of the coronagraph. Halo CMEs are interpreted as CMEs directed toward or away from the observing coronagraph. When the expanding ring does not completely surround the occulting disk, but has an angular width of more than 120 degrees around the disk, the CME is referred to as a partial halo coronal mass ejection . Partial and full halo CMEs have been found to make up about 10% of all CMEs with about 4% of all CMEs being full halo CMEs. Frontside, or Earth-direct, halo CMEs are often associated with Earth-impacting CMEs; however, not all frontside halo CMEs impact Earth. In 2019, researchers used an alternative method ( Weibull distribution ) and estimated
6480-513: The occurrence of gamma-ray emitting solar flares at least since the solar cycle 19 . The period has since been confirmed in most heliophysics data and the interplanetary magnetic field and is commonly known as the Rieger period . The period's resonance harmonics also have been reported from most data types in the heliosphere . The frequency distributions of various flare phenomena can be characterized by power-law distributions . For example,
6570-508: The order of terawatts directed back toward Earth's upper atmosphere . This can result in events such as the March 1989 geomagnetic storm . CMEs, along with solar flares , can disrupt radio transmissions and cause damage to satellites and electrical transmission line facilities, resulting in potentially massive and long-lasting power outages . Shocks in the upper corona driven by CMEs can also accelerate solar energetic particles toward
6660-452: The outer radiation belt , with either a decrease or an increase of relativistic particle fluxes by orders of magnitude. The changes in radiation belt particle fluxes are caused by acceleration, scattering and radial diffusion of relativistic electrons, due to the interactions with various plasma waves . A halo coronal mass ejection is a CME which appears in white-light coronagraph observations as an expanding ring completely surrounding
6750-522: The peak fluxes of radio, extreme ultraviolet, and hard and soft X-ray emissions; total energies; and flare durations (see § Duration ) have been found to follow power-law distributions. The modern classification system for solar flares uses the letters A, B, C, M, or X, according to the peak flux in watts per square metre (W/m ) of soft X-rays with wavelengths 0.1 to 0.8 nanometres (1 to 8 ångströms ), as measured by GOES satellites in geosynchronous orbit . The strength of an event within
6840-412: The plane-of-sky ranging from 20 to 3,200 km/s (12 to 2,000 mi/s) with an average speed of 489 km/s (304 mi/s). Observations of CME speeds indicate that CMEs tend to accelerate or decelerate until they reach the speed of the solar wind ( § Interactions in the heliosphere ). When observed in interplanetary space at distances greater than about 50 solar radii (0.23 AU) away from
6930-456: The process of photoionization . The electrons that are freed in this process, referred to as photoelectrons to distinguish them from the ambient ionospheric electrons, are left with kinetic energies equal to the photon energy in excess of the ionization threshold . In the lower ionosphere where flare impacts are greatest and transport phenomena are less important, the newly liberated photoelectrons lose energy primarily via thermalization with
7020-520: The solar physics branch head, Dr. Tousey. Earlier observations of coronal transients or even phenomena observed visually during solar eclipses are now understood as essentially the same thing. On 1 November 1994, NASA launched the Wind spacecraft as a solar wind monitor to orbit Earth's L 1 Lagrange point as the interplanetary component of the Global Geospace Science (GGS) Program within
7110-423: The solar wind tend to speed up until their speed matches that of the solar wind. How CMEs evolve as they propagate through the heliosphere is poorly understood. Models of their evolution have been proposed that are accurate to some CMEs but not others. Aerodynamic drag and snowplow models assume that ICME evolution is governed by its interactions with the solar wind. Aerodynamic drag alone may be able to account for
7200-416: The solar wind. In the majority of CME events, acceleration is provided by magnetic reconnection cutting the strapping field's connections to the photosphere from below the core and outflow from this reconnection pushing the core upward. When the initial rise occurs, the opposite sides of the strapping field below the rising core are oriented nearly antiparallel to one another and are brought together to form
7290-454: The southern hemisphere and reverse- S sigmoids more common in the northern hemisphere. Magnetic flux ropes—twisted and sheared magnetic flux tubes that can carry electric current and magnetic free energy—are an integral part of the post-eruption CME structure; however, whether flux ropes are always present in the pre-eruption structure or whether they are created during the eruption from a strongly sheared core field (see § Initiation )
7380-488: The speed of the ICME in the frame of reference moving with the solar wind is faster than the local fast magnetosonic speed. Such shocks have been observed directly by coronagraphs in the corona, and are related to type II radio bursts. They are thought to form sometimes as low as 2 R ☉ ( solar radii ). They are also closely linked with the acceleration of solar energetic particles . As ICMEs propagate through
7470-516: The sudden (timescales of minutes to tens of minutes) release of magnetic energy stored in the corona. The same energy releases may also produce coronal mass ejections (CMEs), although the relationship between CMEs and flares is not well understood. Associated with solar flares are flare sprays. They involve faster ejections of material than eruptive prominences , and reach velocities of 20 to 2000 kilometers per second. Flares occur when accelerated charged particles, mainly electrons, interact with
7560-425: The total number in the coronal loop. After the eruption of a solar flare, post-eruption loops made of hot plasma begin to form across the neutral line separating regions of opposite magnetic polarity near the flare's source. These loops extend from the photosphere up into the corona and form along the neutral line at increasingly greater distances from the source as time progresses. The existence of these hot loops
7650-406: The two is not well defined. The SWPC regards events requiring 30 minutes or more to decay to half maximum as LDEs, whereas Belgium's Solar-Terrestrial Centre of Excellence regards events with duration greater than 60 minutes as LDEs. The electromagnetic radiation emitted during a solar flare propagates away from the Sun at the speed of light with intensity inversely proportional to the square of
7740-415: The vertical component of the magnetic field reverses. PILs may exist in, around, and between active regions or form in the quiet Sun between active region remnants. More complex magnetic flux configurations, such as quadrupolar fields, can also host pre-eruption structures. In order for pre-eruption CME structures to develop, large amounts of energy must be stored and be readily available to be released. As
7830-402: Was collected on a Secondary Electron Conduction (SEC) vidicon tube, transferred to the instrument computer after being digitized to 7 bits . Then it was compressed using a simple run-length encoding scheme and sent down to the ground at 200 bit/s. A full, uncompressed image would take 44 minutes to send down to the ground. The telemetry was sent to ground support equipment (GSE) which built up
7920-656: Was developed at the University of Alabama in Huntsville with support from the Space Radiation Analysis Group at Johnson Space Flight Center (NASA/SRAG) for forecasting M- and X-class flares, CMEs, fast CME, and solar energetic particle events. A physics-based method that can predict imminent large solar flares was proposed by Institute for Space-Earth Environmental Research (ISEE), Nagoya University. Coronal mass ejections A coronal mass ejection ( CME )
8010-406: Was the first to report radioastronomical observations of the Sun at 160 MHz. The fast development of radioastronomy revealed new peculiarities of the solar activity like storms and bursts related to the flares. Today, ground-based radiotelescopes observe the Sun from c. 15 MHz up to 400 GHz. Because the Earth's atmosphere absorbs much of the electromagnetic radiation emitted by
8100-467: Was the main, if not the only, source of information about solar flares. Other passband filters are also used. During World War II , on February 25 and 26, 1942, British radar operators observed radiation that Stanley Hey interpreted as solar emission. Their discovery did not go public until the end of the conflict. The same year, Southworth also observed the Sun in radio, but as with Hey, his observations were only known after 1945. In 1943, Grote Reber
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