Solar activity is the general term for all the activities in the solar atmosphere.MainlySunspot、facula、flocculus、solar flare、ProminenceandCoronaTransient events, etc.It is caused by electromagnetic processes in the solar atmosphere.It is sometimes strong and sometimes weak, with an average cycle of 11 years.The sun in the period of intense activity (called the "disturbed sun") emits a lot of ultraviolet rays, x-raysParticle FlowAnd strong radio waves, which often causeaurora, magnetic storm andIonospheric disturbanceAnd so on.
facula: The bright tissue at the edge of the solar photosphere extends outward toChromospherenamelyflocculus。The light spot generally surrounds the sunspot and is closely related to the sunspot.
Plaque: The mottled tissue on the solar photosphere that is brighter than its surroundings.
ProminenceDuring a total solar eclipse, the sun is surrounded by a redRingThere is a bright red flame tongue on it. This flame tongue like object is called a prominence.
Corona: The corona is the outermost layer of the solar atmosphere (its interior isphotosphereLayers andChromosphereLayer), with a thickness of more than several million kilometers.The coronal temperature is 1 million degrees Celsius, and the particle number density is 1015m3.At high temperatures,hydrogen、heliumetc.atomHas beenionizationPositively chargedproton, helium nuclei and negatively charged free electrons, etc.The coronaTotal solar eclipseAnd the use of a coronagraph.
Impact: solar activity on earthquakes, volcanic eruptionsdrought, floods, human heart and nervous system diseases, and even traffic accidents are all related.ThereforeSolar activity predictionThis knowledge.
Sunspot is a kind of solar activity occurring on the photosphere of the sun, which is the most basic and obvious phenomenon in the solar activity.It is actually a huge whirlpool of hot gas on the surface of the sun, like a shallow plate, concave in the middle, and its temperature is 1000 ℃ to 2000 ℃ lower than that on the surface of the photosphere, so it looks "black".[1]
Research History
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As early as about 140 BC, human beings began to have an awareness of the sunsunspotBut people didn't know what it represented at that time.It was not until Carlington, an Englishman, observed and recorded a big eruption in a sunspot area more than 100 years ago that the mystery of sunspots was gradually unveiled.As a result, scientists began to really study sunspots and found that their average activity cycle was 11 years.
The longest record of changes in solar activity isSunspotChanges.The first record of sunspots was about 800 years ago in China, and the oldest description record was about 1128 years ago.In 1610, astronomers began to record sunspots and their movements with telescopes. The initial research focused on nature and behavior.However, sunspotphysical propertyUntil the 20th century, the energy potential was identified, so the observation was still ongoing.In the 17th and 18th centuries, due to the low number of sunspots, research was hindered, but now it is considered that the low tide of solar activity was prolonged, as is knownMonde minimum。Before the 19th century, there were long enough numerical records to infer the periodicity of sunspot activity.In 1845,Princeton University Professor ofJoseph Henry andStephen Alexander useThermopileObserve the sun and confirm that the radiation of sunspots is lower than the solar surface in the surrounding area;Later, the sun'sfaculaThe emitted radiation is higher than the average value.
solar activity
In about 1900, researchers began to explore the correlation between solar activity and the weather on the Earth, especially Charles Greeley Abbott, who led the observation at the Smithsonian Astronomical and Physical Observatory (SAO)solar radiationChanges.Its team must begin with the invention of the instrument for measuring solar radiation. Later, when he became the leader of the SAO, he set up a solar observatory in Kalama, Chile, to supplementMount Wilson ObservatoryInadequate data.He found 27 harmonic periods in 273 month Haile period, including 7, 13, and 39 month modes.He searched for the correlation between the weather through the monthly weather records of the city, such as the trend that temperature changes and rainfall match or oppose the solar activity.With the development of dendrology, such as Waldo S·Glock and other scientists noticed that the growth of trees and the existing recordsSolar cycleThe relationship betweenSolar constantChange, inferring millennial scalechronologyThere are similar changes.
Statistical research shows that the relationship between weather and climate and solar activity is century wide, and the data is pushed back to 1801, whenWilliam Herschel It is noted that there is a clear correlation between wheat prices and sunspot records.They now conduct a highly intensive global comparison with the data collected from the surface network and observed by meteorological satellites to comprehensively or observe how the role of solar variability passes through the EarthClimate systemA detailed process of dispersion and/or forcing the establishment of climate models.
Main signs
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yesSunspotandsolar flare。Flares are the most intense manifestation of solar activity.The climate of the earth (precipitation),the ionosphere(radio short wave communication), magnetic field (with“magnetic storm”Phenomenon) and in the high latitude night skyauroraappear.The average cycle is about 11 years.
Main performance
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Sunspot
SunspotIt is the strong magnetic field activity of the sun that inhibits the effect of convection, so thatsurface temperature Relatively low, darker areas.The number of black spots is related tosolar radiationIn the 1980sAboutFoukal et al.Yuyun 7 (launched on October 25, 1978) andSolar maximum mission satellite(Launched on February 14, 1980) It was found that because the area around the sunspot is brighter, the overall effect is that the more black spots mean the brighter the sun.
solar activity
There were some suggestions that the change of the solar diameter might lead to the change of the output, but the recent work is mainly the Micheson of SOHODopplerThe imager shows that this change is extremely small, only about 0.001% (Dziembowski et al., 2001).All kinds of research have used sunspot numbers (because this record has lasted for hundreds of years) as the proxy for other solar output activities (because the best observation data is only decades old). Similarly, ground instruments and instruments at extremely high orbital heights have also been compared and compared.The researchers combine the current data and adjust the historical data, and other agents' information such ascosmic raysIsotopes produced - used to inferSolar magnetic fieldActivity and possible brightness.
Sunspot's activity has been usedWolff numberThis index (also known asZurich number）Both the number of sunspots and the number of groups are used to compensate for the change in measurement.Ilya Usoskin of Oulu University in Finland pointed out in a research in 2003 that sunspot activities were more frequent since 1940s than in the past 1150 years.During the 11400 year activity period of rebuilding sunspots, there was an obvious active period 8000 years ago.The number of sunspots in 11400 years has been reconstructed through the changes in the concentration of radioactive carbon used in tree aging.The level of solar activity in the past 70 years seems to be abnormal, and the last time a similar huge change occurred about 8000 years ago.The magnetic activity of the sun is about 10% higher than that of the past 11400 years, and the early periods of high activity are shorter than the current events.
Solar cycleIt is the cyclical change of the sun's behavior. Many possible models have been established, but only 11 year and 22 year cycles have been observed clearly.
11 years: the most obvious is that the number of sunspots gradually increases and decreases in the cycle of about 11 years, also becauseSchwabThe observation of is called Schwab period.Babcock Model This cycle is explained by the outflow and involvement of the magnetic field.WhenSunspotThe activity on the sun's surface is also most active when it increases, but the luminosity remains unchanged due to the increase of bright spots（facula)。
22 years: Haier cycle, due toGeorge Ellery HaleNamed.In each Schwab cycle, the sun's magnetic field will be reversed, somagnetic poleIt takes two twists to return to the same magnetic pole.
87 years (70-100 years): The Grasberg cycle, named after Wolfgang Grasberg, is considered the amplitude modulation of Schwab's 11 year cycle (Sonnett and Finney, 1990)Braun, et al, (2005)。
178:Jose(1965)It is found that the angular motion change rate of the sun around the center of mass of the solar system has a period of 178.76 years, and that of the sun around the instantaneous curvature center has a period of 178.70 years.[2]
210 years: Suess period. Suess and de Jong measured the~(14) C content of tree rings with a period of about 200 years. The range of~(14) C content variation obtained from these works is between 1% and 2%, reflecting the modulation of solar wind on cosmic rays in the Milky Way.[3]
2300 years: Halsta period, solar orbital movement and solar angular velocity change have stable Hallstatt characteristic periods. They are all composed of the most basic 22 periods. The peak value of this 22 year period corresponds to the peak value of the odd cycle of solar activity, and the valley value corresponds to the even cycle of solar activity on a Monday. The peak value corresponds to the maximum value of the sunspot magnetic polarity index,The minimum value of the valley value to the sunspot magnetic polarity index indicates that the peak value of the Hallstatt period is also composed of the maximum value of the sunspot magnetic polarity index. Therefore, it can be inferred that the Hallstatt long period of solar activity should also be the magnetic period of solar activity on a millennium scale[2]
Impact on the Earth
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Ionospheric influence
The earth's atmospheresolar radiationFormed under the action of ultraviolet ray, X-ray, etcthe ionosphereThe radio wave of radio communication is transmitted to a long distance by the reflection of the ionosphere.When the sun is active, especiallysolar flareIn the sunny hemisphere, the sun shines stronglyX-ray, ultraviolet ray, etc., which thickens the ionosphere layer D, resulting inlong waveWhile the short wave reflected by layer E and layer F is strongly absorbed by layer D and attenuated or even interrupted when passing through, for example, the long-distance radio station was interrupted for 2 hours on November 5, 1970;This is called "sudden ionospheric disturbance".These reactions occurred almost simultaneously with the eruption of the big flare, becauseelectromagnetic waveThe speed of propagation is the speed of light, which can reach the surface of the earth from the sun in about 8 minutes, so the reaction is very fast.Charged by the flare after passing through a section of elbowHigh-energy particleGradually reaching the earth, they are affected byGeomagnetic fieldAction direction ofGeomagnetic poleBipolar movement, thus affecting the polarthe ionosphere, causing disturbance or even interruption of radar and radio communication in high latitudes.This is called“Electrode cap absorption”And“Auroral zoneAbsorption ", its influence time is long.
wholeearthIt is a large magnetic field.The north pole of the earth isgeomagnetic fieldThe south pole of the earth is geomagneticMagnetic north pole。Earth Pole andmagnetic poleThere is about 11 degrees betweenincluded angleTherefore, the earth is full of magnetic force lines, and different positions have differentGeomagnetic intensity。peacetimeGeomagnetismAffected by many aspects, there will be different degrees of disturbance, and the biggest impact ismagnetic storm 。Magnetic storms generally occur inSolar flare20-40 hours after the eruption, it is a strong disturbance of the geomagnetic field,magnetic field intensityIt can change a lot.At this time, the wind speed of the sun tends to increase, andMagnetopauseThe surface can be separated fromGeocentric8-11Earth radiusIt is compressed to 5-7 earth radii, and the occurrence of magnetic storms will affect human activities, especially the work related to geomagnetism.
Climate Impact
The relationship between solar activity and climate change on the earth is also obvious. Climate change on the earth is closely related to the cycle of sunspot number change, but its specific mechanism is far from clear.Of precipitation in many parts of the worldInterannual changeThere is a certain correlation with the 11 year cycle of sunspot activity.In addition, we just found that,Sub frigid zoneThe annual rings of many trees with very high ages have regular density changes corresponding to the 11 year cycle of sunspot activity.At the same time, from the statistical data, we found that in the peak year of sunspot activity, the earth's specific abnormal climateprobabilityOn the increase;On the contrary, in the low peak year of sunspot activity, the climate on the earth is relatively stable.In addition, the change of the upper atmosphere of the earth is also related to the solar activity.The research on earthquake, hydrology, meteorology and other aspects have all explained the impact of solar activity on the earth, and the physical mechanism of this aspect is still under study.
Influence of magnetic field
The whole earth is a big magnetic field.The north pole of the earth is the magnetic south pole of the geomagnetic field, and the south pole of the earth is the magnetic north pole of the geomagnetic field.There is an angle of about 11 degrees between the earth pole and the magnetic pole, so the earth is full of magnetic lines of force, and different positions have different geomagnetic intensities.At ordinary times, the geomagnetic field is affected in many ways, and there will be disturbances of varying degrees, and the magnetic storm phenomenon is the most influential.
Solar atmosphereCharged particle flow, can make the earthmagnetic fieldDisturbance will produce "magnetic storm" phenomenon, which makes the magnetic needle vibrate violently and cannot indicate the direction correctly.When sunspots andsolar flareWhen it increases, the strong radio emitted will disturb thethe ionosphereThe short wave radio communication on the ground will be affected, or even temporarily interrupted.Magnetic storms generally occur 20-40 hours after the eruption of solar flares. They are strong disturbances of the geomagnetic field, whose intensity can vary greatly.At this time, the solar wind speed tends to increase, and the top surface of the magnetosphere facing the sun canGeocentric8-11 earth radii are compressed to 5-7 earth radii, and the occurrence of magnetic storms will affect human activities, especially the work related to geomagnetism.It will make the compass magnetic needle swing, and cannot correctly indicate the direction, which will affect the ship sailing at sea, the aircraft flying in the air, and even the flying of carrier pigeons.
When a magnetic storm occurs, it is often accompanied byauroraappear.The aurora is often seen at 25-30 degrees above the geomagnetic pole at latitude, 100-300 kilometers above the ground. It is a colorful luminescence phenomenon in the atmosphere, with different shapes.The area where the aurora often appears is called the aurora area.Because fromSolar active regionThe flow of charged high-energy particles ofatomTo produce light by excitation or ionization.When the solar activity is intense, the number of auroras also increases.
Light green and red are often seen in the night sky at the poles of the earth.Pink light band or light arc, which is calledaurora。Aurora isCharged particle flowIt rushes into the upper atmosphere there at a high speed, is captured by the earth's magnetic field, and collides with the thin atmosphere.
The influence of solar activity on the earth;The sun rotates. The active area on the sun sometimes faces the earth, and sometimes faces away from the earth;The earth itself rotates and revolves, so the influence of solar activity on the earth is very complex, and the cycles are also various, such as daily cycle, 27 day cycle, annual cycle, 11 year cycle, etc.This is mainly aboutsolar flareThe impact of fast changing sunspot groups on the earth, the impact of small activities and the various impacts of the calm sun on the earth are not involved.
The effect of flares and sunspots on the Earththe ionosphere, magnetic field and polar region have significant geophysical effects.
Impact of aerospace
largesolar flareHigh energy emitted when appearingproton, which is extremely destructive to space activities.When high-energy protons reach the elbow near the earth, especially in the polar region without radiation belt protection, it will affect the flight in the polar region;In case of satellite, it will damage the instruments and equipment on the satellite;Under the bombardment of high-energy protons, the performance of solar cells will decline seriously and cannot work;In case of astronauts working outside the spaceship, life will be endangered.
When the solar activity reaches its peak, the temperature in the tropical and subtropical regions of the Pacific Ocean on the earth increases, the sea water evaporates rapidly, and the rainfall in the tropical waters of the western Pacific Ocean increases. At the same time, the temperature in the tropical waters of the eastern Pacific Ocean decreases. This phenomenon is similar toLa NinaPhenomenon.In the next year or two, this phenomenon gradually evolved into an El Nino like phenomenon under the effect of solar activity. The slowly moving ocean current brought warm water, replacing the cold water in the tropical waters of the East Pacific.
Generally speaking, the influence of the sun on the earth is mainly reflected in four aspects: 1. Disturbing the earth's skythe ionosphere, ImpactRadio short wave communication；2. Disturbance of the earth's magnetic field, resulting in“magnetic storm”Phenomenon;3. Acting on the upper atmosphere of the two polesaurora；4. Affect the earth's natural environment and cause natural disasters.
Solar radio burst
It is a sudden radio radiation process on the sun.Solar radio includes quiet radio, slowly varying radio and radio burst phenomena.Among them, radio bursts can attract people's attention most.Because this radiation phenomenon often happens very suddenly, and the changes are also very violent. The speed is fast, and the radiation intensity is large. Its intensity is 10 million times greater than that of quiet radio.Solar radio bursts often occur together with flares, X-ray bursts, proton bursts or cosmic ray bursts in solar active regions.When these enhanced radiation reaches the earth, it will produce a series of serious geophysical effects, such as aurora, magnetic explosion, telecommunications interference, and so on.Therefore, further research on radio bursts will be helpful to understand the physics, geophysics, solar terrestrial relationship and the unstable change process of celestial bodies in the solar active region[4]。
application
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From the influence of solar activity on the earth, we can see that it is very necessary to forecast the solar activity.Now many countries, including China, have carried out work in this regard.Through forecasting, relevant departments, such as communication departments and aerospace departments, can take timely measures to reduce the impact of solar activity on the work of these departments, and also provide information for accurate weather, climate, hydrology, earthquake and other forecasts.
