The geomagnetic field refers to the natural magnetic phenomenon existing in the earth's interior.The earth can be regarded as a magnetic dipole, with one pole near the geographical north pole and the other near the geographical south pole.Through these twomagnetic poleThe imaginary straight line (magnetic axis) ofearthThe rotation axis of is inclined at about 11.3 degrees.The earth's magnetic field extends tens of thousands of kilometers into spaceformationearthMagnetic coilGravity.The earth's magnetic circle is a barrier to the earthsolar windThe role of charged particles carried.The Earth's magnetic circle is in the daytime（Sunward(surface) is squeezed by the force of charged particles, and extends outward in the dark night area of the earth (back to the sun).[1]
The geomagnetic field includes basic magnetic field and variable magnetic field.The basic magnetic field is the main part of the geomagnetic field. It originates from the interior of the solid earth, is relatively stable, and belongs to the static magnetic field.The changing magnetic field includes various short-term changes of the geomagnetic field, which mainly originates from the outside of the solid earth and is relatively weak.Earth changing magnetic fieldIt can be divided into two types: calm change and disturbance change.
Marching and navigation use geomagnetic field tocompassThe role of orientation.People can alsoaccording toThe distribution characteristics of geomagnetic field on the ground look for mineral deposits.The variation of the geomagnetic field can affect the propagation of radio waves.Local magnetic field is subject toSunspotWhen strong disturbance occurs due to activities, remote communication will be seriously affected, or even interrupted.If there is no geomagnetic field, the strongCharged particle flow(usually calledsolar wind）Will not be deflected by the geomagnetic field, but will directly shoot at the earth.In this caseHigh-energy particleUnder the bombardment of, the atmosphere of the earth may not be as it is now, and life will not exist.So the geomagnetic field is a "protective umbrella" for us.
The geomagnetic field intensity is about 0.5 -~0.6 gauss, that is, 5~6 * E-5Tesla（50~60μT）。
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geomagnetic field
Written by Shen Kuo (1034-1094), a Chinese scientist in the Song Dynasty, in 1086 A.D《Mengxi Writing》Chinese, the earliest recordedGeomagnetic declination"The Fangs (warlocks) use magnetic stones to grind needle points, which can guide people, but often slightly east, not completely south.".Shen Kuo is the first person in history to study the phenomenon of magnetic deviation from a theoretical perspective.It is the British who put forward the more systematic primitive theoryGilbert。In his book "Magnets" written in 1600, he wrote down many facts about the nature of magnets at that time, and creatively made epoch-making experiments, grinding a natural magnet into a large magnetic ball, and using small wires to make a smallmagnetic needleIt is mounted on the pivot, placed near the magnetic sphere, and found that the various behaviors of the small magnetic needle on the magnetic sphere are similar to those seen on the earthcompassTheir behavior is exactly the same.Gilbert used a stone pen to mark the points of the small magnetic needles and draw many meridian circles, which are similar to the longitude of the earth, but also have oneequator, the small magnetic needle is parallel tosphere。thereforeGilbertHe put forward a theory that the earth itself is a huge magnetmeridianMeet at two opposite ends of the earth, namelymagnetic poleOn.
Origin of geomagnetic field
The reason why the earth has a magnetic field is unknown, and it is generally believed that it is caused by the flow of liquid iron in the core of the earth.The most representativehypothesisYes“Generator theory”。In 1945, American physicist ElsasserMagnetohydrodynamic generatorThe principle ofField nuclearIt moves in the initial weak magnetic field and generates current like a magnetohydrodynamic generator. The magnetic field of the current strengthens the original weak magnetic field. In this way, the external nuclear matter interacts with the magnetic field to strengthen the original weak magnetic field.becausefriction generates heatWhen the magnetic field increases to a certain extent, it will stabilize, forming the current geomagnetic field.
Another hypothesis is that
FerromagneticAt 770 ℃ (Curie temperature), the magnetism will completely disappear.In the high temperature state deep in the formation, iron will reach and exceed its melting point and become liquid, never formingGeomagnetic field。And the application“The electric essence of magnetic phenomena”According to the results of physical research, the extranuclear electrons of the atoms of substances in high temperature and pressure will be accelerated and escape outward.Therefore, a large number of electrons will escape from the earth's core in the environment of 6000K high temperature and 3600000 atmospheric pressure,mantleInterphase formationnegative electricityLayer.according tomaxwellOfElectromagnetic theory, electric generation of magnetism, magnetic generation of electricity.Therefore, to form the north and south polar magnetic field of the earth, it is necessary to form a rotating electric fieldearth rotationIt will inevitably cause the rotation of the negative electric layer of the mantle, that is, the rotating negative electric field, and thus the magnetic field.
geophysicsOne of the basic problems of.Since W. Gilbert of Britain proposed that "the earth is a huge magnet" in 1600, the speculation about the origin of the geomagnetic field has been nearly 400 years, but it has not been satisfactorily solved yet.
A brief history The main part of the geomagnetic field is like an approximately rotating axisUniform magnetizationThe magnetic field of the sphere.Therefore, the "permanent magnet theory" has become the earliest and most natural guess of the origin of the geomagnetic field.When geophysicists suggested that the core of the earth might be composed of iron, nickel and other strong magnetic materials, this conjecture seemed to be supported.However, the temperature inside the earth is much higher than that of ironCurie point(See rock magnetism), so thishypothesisIt cannot be established.Then someone tried to use the rotation and rotation of the charged earthMagnetic effect, temperature difference current andinduced currentetc.Physical effectsTo explain the geomagnetic field, but its magnitude is far from large enough.For example, according to the rotating magnetic effectMagnetizationIt is about 10~10 electromagnetic units, which is about 9 orders of magnitude smaller than the magnetization of 7.2 × 10-2 of a uniform magnetized sphere equivalent to the geomagnetic field.Since no answer can be found from the existing physical laws, some people began to explore new laws.1947 British physicistBlackett(P.M.S. Blackett) found thatmagnetic momentM andangular momentumP satisfaction, where G isUniversal gravitational constant, c is the speed of light, β is the proportional constant, about 0.25.Blackett envisioned this relationship as a new law of physics and an explanation of the origin of the geomagnetic field, which is called the "giant rotation theory".With the support of three celestial bodies, thishypothesisIt once attracted wide attention.In order to verify this result, Blackett specially designed a highly sensitive instrument for measuring weak magnetic field, but the experimental result was negative, so Blackett himself declared to abandon his hypothesis.[2]
Self excited motor theory
geomagnetic field
The "self excitation motor theory" appeared at the same time with the above assumptions.In 1919, J. Larmor first proposed the possibility of rotating conductive fluid to maintain self excited motor, which is the earliest concept of self excited motor theory about the origin of geomagnetic field.In the late 1940s and early 1950s, W.M. Elsasser, E.N. Parker andBrad(E.C. Bullard) et al.With the application of mainframe computers, more complexMagnetohydrodynamicsThe calculation of becomes a reality.In the late 1960s, it was found that the Brad process was unstable.This has put the "self excitation motor theory", which was once considered very promising, into crisis.It was not until 1970 that F.E.M. Lilley corrected the motion mode of the Brad process that the stable "self excitation motor theory" became possible again.1960sPaleomagnetismThe data confirmed that the geomagnetic fieldGeological periodHaving experienced many reversals, the geomagnetic fieldPolarityThe history of the positive and negative directions of the polarity does not show which polarity is more special.This is about the origin of geomagnetism in addition to the "self excitation motor theory"hypothesisIt is difficult to explain.The earth's magnetic field is not special in celestial bodies,Nine planets in the solar systemAt least Jupiter and Mercury inGeomagnetic fieldSimilar internal magnetic field.The sun and manyfixed starIt also has a magnetic field.Parker's research in the 1960s and 1970s shows that the model of the origin of the geomagnetic field may also be applicable to other celestial bodies.Therefore, people now believe that the "self excitation motor theory" is the most promising theory to explain the origin of geomagnetism.
Principle The research idea of magnetohydrodynamics in the Earth's core is how the interaction of conductive fluid and magnetic field changes the original magnetic field andmotion state , this is“Self excitationThe foundation of "generator theory".
Conductive fluid and magnetic field
Mathematicallyelectromagnetic fieldequationAnd fluidsEquation of motionCoupling.Conductive fluid moving in a magnetic field according toFaraday's law of electromagnetic induction, will be generated in the circuit moving with the fluidInduced electromotive force。If the conductor isconductivityIs an infinite ideal conductor,induced currentWill be infinite, which is obviously impossible.If theMagnetic fluxWithout change, the magnetic line of force must move with the fluid, just as the magnetic line of force is firmly stuck to the fluid.This phenomenon is called the "freezing" effect of the magnetic field, that is, the magnetic field and the fluid are completely frozen.At this time, the equation that the magnetic field satisfies is called the "freezing equation".When the conductivity of the fluid is limitedJoule heatIn addition to the loss, the magnetic field will continue to diffuse from the strong region to the weak region.Therefore, in general, the magnetic field in the conductive fluid is controlled by the freezing effect and will continue to diffuse.The equation satisfied at this time is called "diffusion freezing equation".Freezing and diffusion effects, exceptconductivity(λ) Besides, it is also related to the velocity (v) and scale of the fluid（Electromagnetic hydrodynamicsIn, define dimensionlessconstantIs the magnetic viscosity coefficient.When RM>>1, the freezing effect in the fluid will be main;When RM<<1, diffusion will prevail.
Due to the presence of magnetic field, the fluidEquation of motionIn addition to the originalForceIn addition, it will increaseElectromagnetic force。The coupling medium between motion and magnetic field equation is electromagnetic force.
When conducting fluid moves in a magnetic fieldinduced currentTo change the original magnetic field.If the movement is appropriate, it is possible to maintain a certain stable magnetic field.This process is like a normal generator. The conductive fluid is equivalent to the coil of the generator, so the magnetic field is maintained byhypothesisIt is called "generator theory".Of course, apart from this simple similarity, the processes of the two are completely different.stayMagnetic fluidDuring the process, due to the coupling of motion and magnetic field,electromagnetismEquations and fluidsEquation of motionWill becomenonlinear equation 。So far, it is still difficult to solve such complex nonlinear equations.Therefore, the coupling of motion and magnetic field is usually treated as perturbation, and the motion equation and electromagnetic equation are solved respectively.At this time, the two equations are stilllinear equationThe "generator" corresponding to the equation is called "linear generator".[3-4]
Life impact
If the geomagnetic field generated in the core of the earth is free to decay after being excited, its decay life is about 104 years.However, the oldest magnetic rock age measured in paleomagnetism is close to 109 years, which indicates that the life of the geomagnetic field is far beyond its free decay life.In order to maintain such a long-lived geomagnetic field, it is necessary to constantly provide energy to compensateJoule heatLosses.The source of energy in the core of the earth and how to maintain the movement of the energy provided to obtain a long-term stable geomagnetic field are two basic questions to be answered by the generator.
The conductivity of the core is the highest in the earth's interior, about 3 × 10-6 electromagnetic units.Geomagnetic nonDipole fieldThe westward drift of the component shows that the non dipole field source has amantleThe speed magnitude of the movement is 20 kilometers per year.This is more than beingGeological phenomenonThe confirmed movement of the solid crust is 5 orders of magnitude higher, so considering the joule heat loss and movement order, the liquid core is the most favorable place for the geomagnetic generator.
The energy image of the generator is based on the principle of magnetohydrodynamics in the liquid core. The energy conversion process of the generator is the conversion of motion energy and magnetic energy, and the conversion medium isElectromagnetic force。Movement against this electromagnetic force will provide energy to the system, and part of it will be used for compensationJoule heatLoss, which is used to increase the systemMagnetic field energyAnd transmitting electromagnetic energy outside the nucleus to change the magnetic field inside and outside the nucleus.
This process can be expressed by equation:
The right end of the equation is the electromagnetic force, where j is the current density;(Integral to the whole liquid core) represents movement (V) works against electromagnetic force;WH is the total amount in the liquid coreMagnetic energy；J σ is the joule heat loss rate in the liquid core;FE is the electromagnetic energy transmitted outward through the surface of liquid core in unit time.For the stable generator, the magnetic field inside and outside the core does not change with time, and the equation becomes: J σ=AH
That is, to move against electromagnetic forceWorkAll the energy provided is used to compensate the joule heat loss.
The way of providing sports energy andForceofForce division that produces motionElectromagnetic forceIn addition, gravity andHydrostatic pressure, the transformation equation of the internal force energy of the liquid core is:,
Including liquid corekinetic energyReduction rate of;FP is the energy transfer rate of hydrostatic pressure through the surface of the liquid core to the core. Gravity work will be generated both inside and on the surface of the corepotential energyRelease of;FG is the potential energy release rate generated by mass exchange on the surface of liquid core, such asmantleSuch is the energy exchange caused by the matter falling into the core due to gravity differentiation;G τ is the potential energy release due to the non-uniformity of density along the moving direction of the medium, such as thermal convection.During the generator process, the fluid movement does work against the electromagnetic force, either at the cost of reducing the kinetic energy of the system, or provided by the release of gravitational potential energy and the work done by the hydrostatic pressure of the surface fluid, which can also be the combined effect of several factors.When the system is stable, FP+FG+G τ=AH=J σ
At this time, the release of gravitational potential energy and hydrostatic pressureWorkAll are used to compensate for joule heat loss.
From the total energy (WH) of the magnetic field in the core and the free decay time of the magnetic field, it can be estimated thatJoule heatLoss (energy supply rate.[5]
Energy source
Early Elsasser and Brad both assumed a long liferadioactive elementMaintainedThermal convectionIt is the provider of generator energy.It can be estimated from G τ that in order to provide 1017 ergs/s of energy, the heat generation rate per unit mass in the earth's core needs to be as high as 100 ergs/(g · s).However, the heat generation rate of radioactive elements in the crust calculated from the total ground heat flow is only 10-3~10-1 ergs/(g · s), which is obviously unreasonable.Some people claim that the core is formed by solidification of liquid core, and this process continues to this daylatent heatWill maintainthermonuclearThermal convection, which will also encounter difficulties on the order of magnitude.In 1968, W.V.R. Malkus was confirmed by experiments thatPrecessionDue tomantleDifference from the dynamic flatness of the earth core (seeearth rotation）, the two will have different precessionangular velocityThe former is faster than the latter.Since the earth is a flat sphere, the mantle will force the core to have the same movement trend. At this time, the mantle provides energy to the core through FP, which can maintain the geomagnetic generator.In recent years, some people have raised objections to this, saying that its magnitude is far from enough.Others argue that if the chemical differentiation andGravity differentiationIf it is still in progress, the release of gravitational potential energy (G τ, FG) will provide energy.It can be seen that all possible energy sources in the core of the earth involve basic geophysical problems such as the evolution of the earth and the physical state of the earth's interior. It is difficult to get satisfactory answers at present.
Physical model for maintaining geomagnetic field
geomagnetic field
Regardless of the source of power in the earth's core, as long as there is radial movement in the liquid core, the material in the deep layer has small angular momentumSubstance exchangeAs a result, the conservation of angular momentum will make the outer layer rotateangular velocitySlower and faster in the inner layer.From the coordinate system rotating with the earth, the radial motion is affected byCoriolis forceRole of.thismomentThe component in the direction of the rotation axis is the power to change the rotation speed of the inner and outer layers.To investigate the radialangular velocityDifferentialMagnetohydrodynamicsEffect, the angular velocity difference of continuous distribution is simplified to two layers A and B with different angular velocities, the angular velocity of outer layer A is ω A, and the angular velocity of inner layer B is ω B.Let ω B>;ωA，This is called rigid body fluidNuclear model。Suppose there is a weak magnetic field in the liquid core.in consideration ofinterstellarThe magnetic field pervades the entire interstellar space, and the existence of this primitive magnetic field is possible.Due to the freezing effect of the magnetic field, the magnetic field lines will move together with the core.As shown in Figure 1, the magnetic force line of the original magnetic field will be stretched due to the differential rotation of layers A and B, forming a magnetic field in the direction of the weft winding circle.Figure 1a shows the process of the magnetic line of force being stretched when the relative motion starts to pass through half a cycle [[Image:]] to one cycle [[Image:]].Naturally, with the extension of the magnetic line of force, the tension of the magnetic line of force against this tension is also increasing.This process is repeated until the recovery caused by the tension of the magnetic force linemomentAnd mechanical torque due to convection（Coriolis force）When in relative balance, the magnetic field becomes the shape shown in Figure 1bangular velocityIt will also maintain a stable constant.The magnetic field formed in the liquid core as shown in Figure 1b has no radial component, and the magnetic line of force is completely located on the same spherical surface. This field is called the annular field.The annular field shown in Fig. 1b is opposite in the direction of the northern and southern hemispheres.By the above twoMoment balanceThe magnitude of this annular field can be estimated.Considering the freezing effect of the magnetic field, the traditional view is that there will be a strong annular field in the nucleus, and the annular field calculated by Brad can be as high as 500 Gauss.Recently, some people have also raised objections to the existence of such high-intensity annular fields.Since the toroidal field has no radial component, no matter how strong it is, it has a strong radial componentDipole fieldWill not contribute.There is no external transmission of electromagnetic energy in the above process.The above only considers the magnetic effect generated by differential rotation corresponding to the radial movement, and does not consider the magnetic effect of the radial movement itself.Similar to differential rotation, due to the freezing effect, the interaction between the radial motion and the toroidal field pulls or bends the toroidal field, forming a magnetic line of force loop as shown in Figure 2.The above Coriolis force V=2r × (V × w), except thatmomentExternal (making liquid coreangular velocityChange), there will also be a component perpendicular to the rotation axis, and this torque will twist the magnetic force line ring from the latitude direction (Figure 1) toMeridional planeInside.For upward and downward movement, the direction of torque is opposite;Similarly, in the southern hemisphere and the northern hemisphere, the direction of this moment is also opposite.Therefore, although the magnetic force line loops corresponding to the up and down movements are in opposite directions, and the line loops in the northern and southern hemispheres are also in different directions, under the effect of this torqueMagnetic ringIt will be counterclockwise in the same order (Figure 3).Different from the toroidal field, the distorted magnetic field has components in the same direction as the initial weak magnetic field. This kind of elementary process spreads all over the liquid core. The statistical results may strengthen the original weak magnetic field.The above process is called the Elsasser Parker model.In addition to this model, there is the famous Brad Gelman Lilly process, which has similar physical images to the Elsasser model.Both Elsasser and Brad models can prove the existence of stable generators in mathematical theory by solving linear magnetohydrodynamic equations.It can be seen that even the greatly simplified physical image involves a very complex process in the core.The general generator process will involve more complex turbulent motion in the earth core, so some people call it "turbulent generator".
Reversal of geomagnetic field
It belongs to the content of unsteady generator, and so far there is no description of the whole process as the above steady generator.If the convection vortex movement in the liquid core is disturbed, the polarity of the magnetic field may be reversed.For example, Parker has proved that if the vortex motion between the north and south latitudes of 25 ° in the liquid core disappears generally, the geomagnetic field will reverse.Others argue thatGeomagnetic reversalyesNonlinearThe inherent nature of the generator process, that is, the magnetic field and motion are coupled with each other. When the linear generator is no longer maintained to a certain extent, the nonlinear effect will probably reverse the geomagnetic field.
Both the theory of steady state and unsteady state generator process is not perfect at present.The origin of geomagnetic field is still in the research stage
Magnetic field organism
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magnetic field intensity
Like turtleswhale, migratory birds and many other migratory animals can travel thousands of kilometers every year, often passing through the ocean, but also can determine the exact location.Scientists have found that turtles can passGeomagnetic fieldAnd the position of the sun and other stars.But for migrating sea turtles, only“Sense of direction”It is not enough. They may also have a "map" to define their own geographical location and finally reach a specific destination.Chapel, University of North CarolinaHillThe Kenloman research team of the branch school found that green sea turtles are very "sensitive" to the differences in the strength and direction of the geomagnetic field between different geographical locations, and they can draw a map for themselves through the geomagnetic field.[6]
Geographical meridian
The homing pigeon can fly back to distant places without losing its way, which is also due to the help of geomagnetism
The strength of the geomagnetic field is called the geomagnetic induction intensityMagnetic meridianThe included angle with the geographical meridian is calledMagnetic declination, the angle between the geomagnetic field direction and the horizontal direction of the ground somewhere on the earth is calledMagnetic dipThese three physical quantities are called“Three Elements of Geomagnetism”。But from one part of the earth to another nearby,Geomagnetic elementsThe changes are generally very small.
The geomagnetic field map records the basic data of the geomagnetic field at various points on the earth's surface and their change rules. It is used for navigation, aviation, military andGeological workAn indispensable tool.When ships and aircraft are sailingMagnetic compassThe measured value is geomagneticazimuthTherefore, only when the local magnetic declination value is known can the geographical position and navigation route be determined.
magnetic storm
Generally speaking, the change of geomagnetic elements is very small, butsolar activityClosely relatedmagnetic storm , but it happened very suddenly.that is becauseSunspotWhen the activity is intense, the energy released is equivalent to the power of hundreds of thousands of hydrogen bombs, and a large number of charged particles are ejected at the same time.The strong magnetic field formed by these charged particles shooting on the earth is superimposed on the geomagnetic field, which makes the geomagnetic elements change sharply under normal conditions, causing“magnetic storm”。When a magnetic storm occurs, many strange phenomena will occur on the earth.Beautiful things will appear over the dark Arcticaurora。compassWill swing,Radio shortwaveWhen the radio is suddenly interrupted, pigeons relying on the geomagnetic field to "navigate" will also lose their way and fly around.Geomagnetic field can blockcosmic raysAnd high-energy charged particles from the sun are the natural protective umbrella for organisms from harm.
Therefore, this "super huge" geomagnetic field has formed a "protective shield" for the earth, reducing the invasion of cosmic rays from space, so that life on the earth can survive and grow.Without this shield, the alien cosmic rays will kill all the seedlings of life that first appeared on the earth, and can not breed on the earth at all.[7]
hidden resources
The rocks and minerals in some areas of the earth are magnetic, and the geomagnetic field will undergo drastic changes in the areas where these minerals are buriedGeomagnetic anomalyIt can detect mineral resources and find underground resources such as iron, nickel, chromium, gold and oil.
Geomagnetic field formation
Before a strong earthquake, the three elements of geomagnetism will also change, causing geomagnetismLocal anomalyOf“Seismomagnetic effect”。This is because many of the rocks in the crust are magnetic. When these rocks are deformed by force, their magnetism will change accordingly, so that "pre earthquake prediction" can be made more correctly.
Multiple flips
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Little compass
Scientists have found that the earth's magnetic field has reversed many times through the study of submarine lava.As we all know, blazingMagmaIt contains tens of thousands of minerals, just like "smallcompass”。When the magma cooled down, these "compasses" were also fixed and did not change.In this way, the orientation of its "North and South Poles" recorded the timeGeomagnetic fieldDirection of.Research shows that the earth's magnetic field turns over once every 500000 years on average, and the most recent turn occurred 780000 years ago.As the magnetic field has been weakening for more than one hundred years, people can not help worrying whether another "big change" of the earth's magnetic field is coming?
Molten body
Scientists pointed out that the iron fluid (molten body) existing around the core of the earth is like a "motor", which constantly converts huge mechanical energy into electromagnetic energy, thus forming the geomagnetic field.The iron fluid sometimes forms a huge vortex, forcing its own flow direction to change, which causesGeomagnetic fieldChanges.The reversal of the geomagnetic field is an extremely long process, which takes about 5000 to 7000 years to complete.Originally, this is not a terrible thing, but in this process, the earth magnetic field that protects human beings from strong ionizing radiation will completely disappear, which will cause extremely serious consequences.
Pole transformation
For humans and all living things, the geomagnetic transformation is catastrophic.After the disappearance of geomagnetismradialThe city will reach the surface directly, and the living creatures on the earth will lose their "protective umbrella" and be damaged by strong radiation.Other scientists believe that changes in the geomagnetic field lead tochromosome aberration, it will cause animals and plants to grow differently, and it will also make some suppressedcrustal movementadvance.Therefore,Geomagnetic poleThe transformation of human beings is the biggest threat facing mankind.Will the geomagnetism really disappear?
It is an indisputable fact that there is an electric current flowing on the earth under our feet.Because we know thatsolar windWhen the current in the earth is strong, it can burn power supply equipment and various communication equipment, and sometimes even oil pipelines.The "Basic Geophysics" taught by undergraduate geosciences students also includes“geoelectricity ”A branch of the subject.
Some people say that we can neither see nor measure the current in the earth.So it is difficult for us to discuss them.But we start from the modern discipline《electromagnetics》We know: "The flowing current will produce magnetic field, and the changing magnetic field will produce current." Based on this, we can conclude that:Earth currentThe performance above the ground isGeomagnetic field。Since the earth's magnetic field is known, we can assume some boundary conditions;In this way, theoretical trial calculation can be carried out to obtain the approximate state of the earth current.Electric field and magnetic field complement each other, and those on the earth are no exception.
As mentioned above, the earth current geomagnetic field theory should be the cause of the earth's magnetic field.Some people may ask that the theory of the earth's magnetic field is generally believed by the modern scientific community to be:earth 's coreRelative autorotation generator theory.actuallyGeonuclear generatorThe theory of magnetic field is a very unrealistic idea.People with modern scientific knowledge should know that no matter how you design its structure, it is impossible to generate electricity to form a vast magnetic field in a planetary body that rotates independently without external interference, because it does not have energy sources.
Upwarp of magnetic inclination
At the beginning of last century, people realized that:Remanent magnetismIt records the magnetic field characteristics when rocks were formed at that time.In more than half a century, people have surveyed all kinds of stones that can be found.The measurement results are shocking: the residual magnetic field direction of most rocks is exactly opposite to the local magnetic field direction, and the magnetic dip angle of the reverse residual magnetic field is no longer sagging, it becomes warping (the higher the latitude, the greater the value of warping).In order to explain the reversal of the residual magnetic field of rocks, in 1928, the JapaneseSongshan base modelSaid: It was at that timeGeomagnetic fieldFlipped.Because no one can put forward a better explanation, the geomagnetic inversion theory has become the natural explanation of the academic community.Up to now, no one has been able to explain the phenomenon of the upward tilt of the reverse remanent magnetism, and the geoscientists dare not even mention it.
According to the shape of the geomagnetic field,Earth currentIt should be a thin earth layer flowing along the latitude in the crust.It's inequatorThe current nearby is the largest, atBipolarThe current at is very low.The current layer is not fixed at a certain position in the crust, and the evolution of the earth makes the current layer fluctuate up and down in the crust.In the evolution of the earthEarth currentThe cooled rocks above the layer are positive remanence with downward magnetic dip.The remanence of rocks formed below the earth current layer is reverse magnetism, and the magnetic dip angle is upward.The rock formed in the middle of the earth current layer has no remanence.The interpretation of the remanent magnetic inversion of rocks by using the telluric current layer can be in good agreement with the actual situation.This explanation should be what actually happened.During the evolution of the earth, the geomagnetic field does not need overturning, nor does it have overturning mechanism and other biological manifestations.
Sunspot
geomagnetic field
Mayans once predicted that there might be great changes in human beings in 2012.Just according to the solar cycle, 2012 is alsoSunspotActivity peak year.First Russian scientists, then Indian and other scientists believe that,Geomagnetic fieldIn the process of weakening, if the earth's magnetic field is to be reversed, it will be reversed.In this way, human beings and earth creatures will face huge disasters.Chinese scientists believe that those who say these words are amateur scientists, and their conclusions are not reliable.
test method
aboutGeomagnetic fieldWhy has it weakened in recent years,Earth currentI have discussed in detail in the book "Earth's Magnetic Field" about the energy source and other issues.I hope you are interested.The book is published by China News Union Press. The introduction is as follows:si'nanPhenomenon, frightening thunder and lightning, incomprehensibleEl Nino Phenomenon and magicBermudaDisappearance in the Triangle Sea area.They have given people endless reverie.In fact, they are all natural phenomena caused by the magnetic field acting on the earth's surface.The book gives theoretical explanations and test methods for these natural phenomena.
Geomagnetic body
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yesHuman nervous systemEffects of magnetic field: under the action of magnetic field, the synthesis and release of stimulated secretions increase. Some studies show that low magnetic field often increases the activity of animals,Excitabilityincrease;The stronger magnetic field often reduces the activity of the organism, reduces the excitability, and presents an inhibitory reaction.In addition, the magnetic field also has effects on autonomic nerves, and has certain effects on heartbeat, blood pressure, and respiration.
Effect on the structure and characteristics of cell membrane: Grandolfo et al. proposed that magnetic field can affect the static and dynamic membrane characteristics of cells after research;On the other hand, low-frequency magnetic field can not only affect the basic structure of cell membrane, but also increase theDiffusivityAnd then affect thepermeability；
Promote bone growth: magnetic field can promoteOsteoblastA certain strength of static magnetic field can increase the concentration of calcium ions in osteoblasts, and a certain strength of static magnetic field can promote the proliferation and differentiation of osteoblasts. The possible reason is that under the effect of static magnetic field, the cell membranecalcium ion channelsOpen, a large number of extracellular calcium ions enter the cell or may be intracellular“Calcium bank”The result of mass release
