Solar flare is an intense eruption of electromagnetic radiation in the sun’s atmosphere. Flares are common in active regions, and they are typically accompanied by coronal mass ejections and solar particle events, but not always. Solar flares have a power-law spectrum of magnitudes; a clear detectable event requires an energy release of approximately 1020 joules, whereas a big event can emit up to 1025 joules. Although they were first discovered in the visible electromagnetic spectrum, particularly in the hydrogen H emission line, they can now be identified in anything from radio waves to gamma rays.
History of Solar flare:
Optical observations
Richard Carrington and Richard Hodgson independently detected solar flares for the first time on September 1, 1859, by projecting the picture of the solar disc created by an optical telescope through a broad-band filter. It was an extremely bright white light flare, one that emitted a lot of light in the visible range.
Because flares emit a lot of radiation at H, adding a narrow passband filter centered on this wavelength to an optical telescope allows small telescopes to see flares that aren’t particularly bright. H was the main, if not the only, source of knowledge about solar flares for many years. There are numerous more passband filters in use.
Radio observations
During World War II, British radar operators observed radiation that Stanley Hey mistook for sun output on February 25 and 26, 1942. Their discovery was not made public until the war was done.
In the same year, Southworth made a radio observation of the sun, but his findings were only discovered after 1945, similar to Hey’s. Grote Reber was the first person to publish radio astronomical observations of the Sun at 160 MHz, which he did in 1943.
The rapid advancement of radio astronomy revealed new aspects of solar activity, such as storms and bursts associated with flares. Ground-based radio telescopes now see the Sun at frequencies ranging from 15 MHz to 400 GHz.
Space telescopes
Telescopes have been launched to space since the beginning of space exploration, where it is possible to detect wavelengths shorter than UV, which are absorbed by the Earth’s atmosphere, and where flares can be quite brilliant.
The GOES series of satellites have been observing the sun in soft X-rays since the 1970s, and its observations have replaced the H classification as the conventional measure of flares. Much different equipment has seen hard X-rays, with the Reuven Ramaty High Energy Solar Spectroscopic Imager being the most important today (RHESSI).
Nonetheless, UV observations are the stars of solar imaging today, because of their remarkable fine details that expose the solar corona’s intricacy. Radio detectors with extremely long wavelengths (as long as a few kilometers) that cannot propagate through the ionosphere may also be carried by spacecraft.
Summary:
Stanley Hey mistook radio radiation for sun output during World War II. The GOES series of satellites have been observing the Sun in soft X-rays since the 1970s.
Optical telescopes
The Big Bear Solar Observatory, which is maintained by the New Jersey Institute of Technology and is located in Big Bear Lake, California, is a solar dedicated observatory with many instruments and a large data bank of whole disc H pictures.
The Institute for Solar Physics (Sweden) operates the Swedish 1-m Solar Telescope, which is housed in the Observatorio del Roque de Los Muchachos on the island of La Palma (Spain). The world’s largest solar telescope, the McMath-Pierce Solar Telescope, is located at Kitt Peak National Observatory in Arizona.
Radio telescopes
The NançayRadioheliographe (NRH) is a 48-antenna interferometer that observes at meter-decimeter wavelengths. The radio heliograph is on display at France’s Nançay Radio Observatory.
The Owens Valley Solar Array (OVSA) is a radio interferometer run by the New Jersey Institute of Technology that initially had seven antennas and could observe frequencies between 1 and 18 GHz in both left and right circular polarisation.
Owens Valley, California is home to OVSA. After an expansion to improve its control system and raise the total number of antennas to 15, it is now known as the Expanded Owens Valley Solar Array (EOVSA).
The NobeyamaRadioheliograph (NoRH) is an interferometer made up of 84 tiny (80 cm) antennas that operate at 17 GHz (left and right polarisation) and 34 GHz simultaneously at the Nobeyama Radio Observatory in Japan. It keeps a constant eye on the Sun, taking daily photos.
The Siberian Solar Radio Telescope (SSRT) is a special-purpose solar radio telescope built to research solar activity in the microwave band (5.7 GHz), where events in the solar corona can be observed throughout the whole solar disc.
It’s a crossing interferometer with two arrays of 128x128 parabolic antennas, every 2.5 meters in diameter, placed 4.9 meters apart and orientated in the E-W and N-S directions. It is located 220 kilometers from Irkutsk, Russia, in a wooded valley between two mountain peaks of the Eastern Sayan Mountains and Khamar-Daban.
Summary
The Big Bear Solar Observatory is a dedicated observatory with many instruments and a large data bank of whole disc H pictures. The world’s largest solar telescope, the McMath-Pierce Solar Telescope, is located at Kitt Peak National Observatory in Arizona. It keeps a constant eye on the Sun, taking daily photos.
Facts about Solar Flare
Description
All layers of the solar atmosphere are affected by solar flares (photosphere, chromosphere, and corona). The plasma medium is heated to tens of millions of degrees Kelvin, and electrons, protons, and heavier ions are propelled to speeds approaching that of light.
Flares emit electromagnetic radiation at all wavelengths, from radio waves to gamma rays, spanning the electromagnetic spectrum. The majority of the energy is dispersed over frequencies outside of our visual range; the majority of flares are invisible to the eye and must be viewed using specific tools.
Flares are seen in active regions, such as those seen surrounding sunspots, where powerful magnetic fields inject the photosphere and connect the corona to the solar interior. The abrupt release of magnetic energy held in the corona (timescales of minutes to tens of minutes) powers flares.
Frequency
The frequency of solar flares changes during the 11-year solar cycle. During solar maximum, it can be numerous every day, down to less than one per week during solar minimum. Furthermore, stronger flares are less common than weaker ones.
For example, X10-class (severe) flares occur around eight times every cycle on average, but M1-class (minor) flares occur roughly 2000 times per cycle on average.
Since the solar cycle 19, Erich Rieger and colleagues observed a 154-day interval in the occurrence of gamma-ray producing solar flares in 1984. Since then, most heliophysics data and the interplanetary magnetic field have verified the time, which is now known as the Rieger period. Most data kinds in the heliosphere have provided the period’s resonance harmonics as well.
Causes of a solar flare
When accelerated charged particles, primarily electrons, collide with the plasma medium, flares erupt. This tremendous acceleration of charged particles is thought to be caused by the phenomena of magnetic reconnection, according to evidence.
Magnetic reconnection on the Sun can occur on solar arcades, which are a series of closely spaced loops that follow magnetic lines of force. These lines of force swiftly reattach into a lower arcade of loops, leaving a magnetic field helix disconnected from the rest of the arcade.
The particle acceleration is caused by the abrupt release of energy during this reconnection. The material contained in the disconnected magnetic helical field may forcefully expand outwards, generating a coronal mass ejection.
This also explains why solar flares usually originate from the Sun’s active regions, which have significantly stronger magnetic fields. Although the source of a flare’s energy is widely accepted, the mechanisms involved are still poorly understood.
It’s unclear how the magnetic energy of the particles is converted into kinetic energy, and how some particles can be accelerated to the GeV range (109 electron volt) and beyond. There are also some discrepancies in the total number of accelerated particles, which appears to be higher than the total number of particles in the coronal loop at times. Flares are impossible to predict, according to scientists.
Summary
Flares emit electromagnetic radiation at all wavelengths, from radio waves to gamma rays, spanning the electromagnetic spectrum. During solar maximum, it can be numerous every day, down to less than one per week during solar minimum.
Flares are seen in active regions, such as those seen surrounding sunspots. The Sun’s coronal mass ejection is caused by accelerated charged particles colliding with the interstellar medium.
Classification
Soft X-ray classification
The letters A, B, C, M, or X are used in the contemporary classification system for solar flares, based on the peak flux in watts per square meter (W/m2) of soft X-rays of wavelengths 0.1 to 0.8 nanometres (1 to 8 ngströms) detected at the Earth by the GOES spacecraft.
A number suffix ranging from 1 to 10, but excluding 10, indicates the strength of an event inside a class, which is also the factor for that event within the class. As a result, an X2 flare is twice as potent as an X1, an X3 flare is three times as powerful as an X1, and an X4 flare is just 50% more powerful than an X2.
An X2 flare has four times the power of an M5 flare. A number suffix equal to or greater than 10 may be used to identify X-class flares with a peak flux of more than 103 W/m2.
H-alpha classification
H spectral observations were used to classify flares previously. Both the intensity and the emission surface are used in this technique. Flares are classified as faint (f), normal (n), or brilliant (b) depending on their intensity (b).
Hazards
Solar flares have a significant impact on the local space weather in the Earth’s vicinity. Solar particle events are streams of very energetic particles produced by them in the solar wind. These particles have the potential to disrupt the Earth’s magnetosphere, posing a radiation risk to spacecraft and astronauts.
Massive solar flares can also be accompanied by coronal mass ejections (CMEs), which have been known to destroy satellites and knock out terrestrial electric power grids for extended periods.
The mild X-ray radiation of X-class flares enhances upper-atmosphere ionization, which can interfere with short-wave radio transmission and heat the outer atmosphere, increasing drag on low-orbiting satellites and causing orbital decay.
The aurora borealis and aurora australis are caused by energetic particles in the magnetosphere. Hard X-rays, which are often the product of huge plasma ejections in the upper chromosphere, can be harmful to spacecraft electronics.
Solar flare radiation is a serious worry in discussions of sending humans to Mars, the Moon, or other planets. Energetic protons can flow through the human body and cause metabolic damage, posing a risk to astronauts on interplanetary missions. To keep the astronauts safe, some type of physical or magnetic shielding would be required.
Most proton storms take at least two hours to reach Earth’s orbit from the time of visual observation. On January 20, 2005, a solar flare delivered the largest concentration of protons ever directly measured, leaving men on the moon with little time to escape safely.
Summary
The letters A, B, C, M, or X are used in the contemporary classification system for solar flares. They are based on the peak flux in watts per square meter (W/m2) of soft X-rays detected at the Earth by the GOES spacecraft. Solar particle events are streams of very energetic particles produced by them in the solar wind.
Frequently Asked Questions
People usually ask many questions about “solare flare”, some of these questions are given below:
1: Why do solar flares happen?
Flares occur when the Sun’s powerful magnetic fields become tangled. When tangled magnetic fields “snap,” they release energy, similar to when a rubber band snaps when twisted too much. Solar flares erupted from the Sun’s strong magnetic fields in the vicinity of active zones.
2: How does a solar flare work?
When magnetic energy that has built up in the solar atmosphere is abruptly released, it causes a solar flare. From radio waves at the long-wavelength end to x-rays and gamma rays at the short-wavelength end, radiation is emitted across almost the whole electromagnetic spectrum.
3: What does solar flare look like?
Solar flares, even though some of them might endure for a long period, usually happen too quickly to be seen with the human eye. They appear as brilliant bursts of light that “flare-up” on the sun’s surface and can only be seen and measured with specialized equipment.
4: What happens when a solar flare explodes?
The radiation released by a solar flare can interfere with our radio communications here on Earth if it is highly powerful. A coronal mass ejection (CME) is a coronal mass ejection that occurs when a solar flare occurs. When the Sun’s magnetic field lines rearrange, they erupt into space at a tremendous rate.
5: Can solar flares affect the brain?
Studies on the effect of geomagnetic storms on the functional state of the human brain in healthy adult women patients (permanent group) in states of relaxation, photo-stimulation, and hyperventilation revealed that severe geomagnetic storms hurt the human brain’s functional state.
6: Would cars work after a solar flare?
According to the EMP test, around 15% of running vehicles could shut down if they were exposed to an EMP bombardment with a voltage of 25kV/m or higher across a large region. To put it another way, short of a big solar flare, only a nuclear eruption or a purpose-built EMP could generate the kind of pulse required to trigger the shutdown effect.
7: What is the difference between a solar flare and a solar storm?
Coronal mass ejections, or CMEs, are huge clouds of particles ejected from the Sun’s atmosphere into space. A solar storm is a word that describes the atmospheric consequences that occur on Earth as a result of occurrences on the Sun such as coronal mass ejections and solar flares.
8: Was there a solar flare in 1983?
While the program created this spectacular 1983 space weather catastrophe, the terrible military ramifications aren’t as far-fetched as they appear. The term “solar storm” refers to a space weather event in which the Sun, during a period of increased activity, hurls harmful particles and radiation our way.
9: Is a corona a halo?
A corona is made up of numerous concentric, pastel-colored rings surrounding a celestial object, as well as a central luminous spot is known as the aureole. Coronae differ from halos in that they are created by refraction (rather than diffraction) of massive ice crystals rather than small ones.
10: Why is the corona so hot?
New research reveals that small nanoflares are responsible for the Sun’s scorching corona. The outer atmosphere of our Sun is mysteriously considerably hotter than its surface. Nanoflares, which are little explosions on the sun surface that occur at random and disperse quickly, is one proposed mechanism.
Conclusion
A solar flare is an intense eruption of electromagnetic radiation in the Sun’s atmosphere. Flares are common in active regions, and they are typically accompanied by coronal mass ejections and solar particle events.
They were first discovered in the visible electromagnetic spectrum, particularly in the hydrogen H emission line. The GOES series of satellites have been observing the Sun in soft X-rays since the 1970s. The Big Bear Solar Observatory is a solar dedicated observatory in Big Bear Lake, California.
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