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A solar flare observed by Hinode in the G-band. It can be seen as two narrow, elongated, bright structures (ribbons) over the southern part of the sunspot.
A solar flare observed by Hinode in the G-band. Hinode (ひので Japanese: "Sunrise" formerly known as Solar-B, is a Japan Aerospace Exploration Agency Solar mission with It can be seen as two narrow, elongated, bright structures (ribbons) over the southern part of the sunspot.

A solar flare is a violent explosion in a star's( like the Sun's) atmosphere releasing up to a total energy of 6 × 1025 Joules. The Sun (Sol is the Star at the center of the Solar System. In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity [1] Solar flares take place in the solar corona and chromosphere, heating plasma to tens of millions of kelvins and accelerating electrons, protons and heavier ions to near the speed of light. A corona is a type of plasma " atmosphere " of the Sun or other celestial body extending millions of Kilometres into space most easily The chromosphere (literally "colour sphere" is a thin layer of the Sun 's atmosphere just above the Photosphere, roughly 10000 kilometres deep In Physics and Chemistry, plasma is an Ionized Gas, in which a certain proportion of Electrons are free rather than being bound The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge They produce electromagnetic radiation across the electromagnetic spectrum at all wavelengths from long-wave radio to the shortest wavelength gamma rays. Electromagnetic radiation takes the form of self-propagating Waves in a Vacuum or in Matter. The electromagnetic (EM spectrum is the range of all possible Electromagnetic radiation frequencies In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency. Radio frequency ( RF) is a Frequency or rate of Oscillation within the range of about 3 Hz to 300 GHz Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions [2] Most flares occur in active regions around sunspots, where intense magnetic fields emerge from the Sun's surface into the corona. A sunspot is a region on the Sun 's surface ( Photosphere) that is marked by intense magnetic activity which inhibits Convection, forming Flares are powered by the sudden (timescales of minutes to tens of minutes) release of magnetic energy stored in the corona.

X-rays and UV radiation emitted by solar flares can affect Earth's ionosphere and disrupt long-range radio communications. The ionosphere is the uppermost part of the atmosphere, distinguished because it is Ionized by solar radiation Direct radio emission at decimetric wavelengths may disturb operation of radars and other devices operating at these frequencies.

Solar flares were first observed on the Sun in by Carrington and independently by Hodgson in 1859 as localized brightenings in a sunspot group. Carrington and Carington are Surnames shared by several notable people including those listed below Year 1859 ( MDCCCLIX) was a Common year starting on Saturday (link will display the full calendar of the Gregorian calendar (or a Common Stellar flares have also been observed on a variety of other stars.

The frequency of occurrence of solar flares varies, from several per day when the Sun is particularly "active" to less than one each week when the Sun is "quiet". Large flares are less frequent than smaller ones. Solar activity varies with an 11-year cycle (the solar cycle). The solar cycle, or the solar magnetic activity cycle, is the main source of periodic variation of all solar phenomena driving variations in Space weather. At the peak of the cycle there are typically more sunspots on the Sun, and hence more solar flares.

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Classification of flares

Solar flares are classified as A, B, C, M or X according to the peak flux (in watts per square meter, W/m²) of 100 to 800 picometer X-rays near Earth, as measured on the GOES spacecraft. A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth X-radiation (composed of X-rays) is a form of Electromagnetic radiation. The Geostationary Operational Environmental Satellite (or GOES) program is a key element in United States' National Weather Service (NWS operations Each class has a peak flux ten times greater than the preceding one, with X class flares having a peak flux of order 10-4 W/m². Within a class there is a linear scale from 1 to 9, so an X2 flare is twice as powerful as an X1 flare, and is four times more powerful than an M5 flare. The more powerful M and X class flares are often associated with a variety of effects on the near-Earth space environment. Although the GOES classification is commonly used to indicate the size of a flare, it is only one measure.

Soft X-ray light curves showing solar flares of different sizes and durations. The red curve represents the total flux in the band 1 to 8 Angstrom, and the blue curve is the flux in 0.5 to 4 Angstrom. Basically, this means that the curves represent the evolution in time of the X-ray power emitted by the Sun in two energy ranges. Each one of the numerous spikes in the curves represents a temporary increase in the emission due to a solar flare.
Soft X-ray light curves showing solar flares of different sizes and durations. The red curve represents the total flux in the band 1 to 8 Angstrom, and the blue curve is the flux in 0. 5 to 4 Angstrom. Basically, this means that the curves represent the evolution in time of the X-ray power emitted by the Sun in two energy ranges. Each one of the numerous spikes in the curves represents a temporary increase in the emission due to a solar flare.

Two of the largest GOES flares were the X20 events (2 mW/m²) recorded on August 16, 1989 and April 2, 2001. Events 1384 - The Hongwu Emperor of Ming China, Emperor Dong hears a case of a couple who tore paper money bills while fighting Year 1989 ( MCMLXXXIX) was a Common year starting on Sunday (link displays 1989 Gregorian calendar) Events 68 - Galba, Governor of Hispania, names himself legatus senatus populique Romani, breaking the line of Year 2001 ( MMI) was a Common year starting on Monday according to the Gregorian calendar. However, these events were outshone by a flare on November 4, 2003 that was the most powerful X-ray flare ever recorded. Events 1333 - Flood of the Arno River, causing massive damage in Florence as recorded by the Florentine chronicler Giovanni Villani Year 2003 ( MMIII) was a Common year starting on Wednesday of the Gregorian calendar. This flare was originally classified as X28 (2. 8 mW/m²). However, the GOES detectors were saturated at the peak of the flare, and it is now thought that the flare was between X40 (4. 0 mW/m²) and X45 (4. 5 mW/m²), based on the influence of the event on the earth's atmosphere (see [1]). The flare originated in sunspot region 10486, which is shown in the illustration above several days before the flare.

The most powerful flare of the last 500 years is believed to have occurred in September 1859: it was seen by British astronomer Richard Carrington and left a trace in Greenland ice in the form of nitrates and beryllium-10, which allow its strength to be measured today (New Scientist, 2005). Richard Christopher Carrington ( May 26 1826 &ndash November 27 1875) was an English amateur Astronomer who discovered Greenland (Kalaallit Nunaat meaning "Land of the Greenlanders" Grønland is a self-governing Danish Province located between the In Inorganic chemistry, a nitrate is a salt of Nitric acid with an Ion composed of one Nitrogen and three Oxygen atoms Beryllium (bəˈrɪliəm is a Chemical element with the symbol Be and Atomic number 4

Hazards

Filament erupting during a solar flare, seen at EUV wavelengths that show both emission and absorption (the filament has both). The plasma physics involved in this process remains poorly understood, but it certainly involves the Sun's magnetic field.
Filament erupting during a solar flare, seen at EUV wavelengths that show both emission and absorption (the filament has both). A prominence is a large bright feature extending outward from the Sun's surface often in a loop configuration The plasma physics involved in this process remains poorly understood, but it certainly involves the Sun's magnetic field. In Physics and Chemistry, plasma is an Ionized Gas, in which a certain proportion of Electrons are free rather than being bound A stellar magnetic field is a Magnetic field generated by the motion of conductive plasma inside a Main sequence ( Hydrogen -burning [3]

Solar flares and associated Coronal Mass Ejections (CMEs) strongly influence our local space weather. A coronal mass ejection (CME is an ejection of material from the solar Corona, usually observed with a white-light Coronagraph. Space weather is the concept of changing environmental conditions in Outer space. They produce streams of highly energetic particles in the solar wind and the Earth's magnetosphere that can present radiation hazards to spacecraft and astronauts. The solar wind is a Stream of charged particles&mdasha plasma &mdashthat are ejected from the upper atmosphere of the Sun. A magnetosphere' is a highly magnetized region around and possessed by an Astronomical object. Radiation, as in Physics, is Energy in the form of waves or moving Subatomic particles emitted by an atom or other body as it changes from a higher energy The soft X-ray flux of X class flares increases the ionisation of the upper atmosphere, which can interfere with short-wave radio communication, and can increase the drag on low orbiting satellites, leading to orbital decay. Energetic particles in the magnetosphere contribute to the aurora borealis and aurora australis.

Solar flares release a cascade of high energy particles known as a proton storm. Protons can pass through the human body, doing biochemical damage. Biochemistry is the study of the chemical processes in living Organisms It deals with the Structure and function of cellular components such as Most proton storms take two or more hours from the time of visual detection to reach Earth. A solar flare on January 20, 2005 released the highest concentration of protons ever directly measured[4], taking only 15 minutes after observation to reach Earth, indicating a velocity of approximately one-third light speed.

The radiation risk posed by solar flares and CMEs is one of the major concerns in discussions of manned missions to Mars or to the moon. Some kind of physical or magnetic shielding would be required to protect the astronauts. Originally it was thought that astronauts would have two hours time to get into shelter, but based on the January 20, 2005 event, they may have as little as 15 minutes to do so. Events 250 - Emperor Decius begins a widespread persecution of Christians in Rome. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar.

Hinode spacecraft

A new spacecraft Hinode, originally called Solar B, was launched by the Japan Aerospace Exploration Agency in September of 2006 to observe solar flares in more precise detail. Hinode (ひので Japanese: "Sunrise" formerly known as Solar-B, is a Japan Aerospace Exploration Agency Solar mission with The, or JAXA, is Japan's national Aerospace agency JAXA was formed on October 1 2003 as an Independent Administrative Institution through the Its instrumentation, supplied by an international collaboration including Norway, the U. K. , and the U. S. , focuses on the powerful magnetic fields thought to be the source of solar flares. Such studies shed light on the causes of this activity, possibly helping to forecast future flares and thus minimize their dangerous effects on to satellites and astronauts. See [2].

See also

References

  1. ^ Kopp, G. A coronal mass ejection (CME is an ejection of material from the solar Corona, usually observed with a white-light Coronagraph. A geomagnetic storm or solar storm is a temporary disturbance of the Earth 's Magnetosphere caused by a disturbance in Space weather. Events 462 - Possible start of first Byzantine indiction cycle. Year 1859 ( MDCCCLIX) was a Common year starting on Saturday (link will display the full calendar of the Gregorian calendar (or a Common ; Lawrence, G and Rottman, G. (2005). "The Total Irradiance Monitor (TIM): Science Results". Solar Physics 230: 129-139.  
  2. ^ Önel, H. ; Mann, G and Sedlmayr, E. (2007). "Propagation of energetic electrons through the solar corona and the interplanetary medium". Astronomy & Astrophysics 463: 1143-1152.  
  3. ^ A Solar Filament Lifts Off. Retrieved on 2006-06-12. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1381 - Peasants' Revolt: in England, rebels arrive at Blackheath.
  4. ^ A New Kind of Solar Storm

External links

References

Dictionary

solar flare

-noun

  1. a violent explosion in the Sun's atmosphere
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